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Gold, Scott Alan. "Nitrogen incorporation in thin silicon oxide films for passivation of silicon solar cell surfaces." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/11101.
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Liu, Qiudi. "Optimization and Characterization of Transparent Oxide Layers for CIGS solar cells fabrication." Connect to full text in OhioLINK ETD Center, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1187376131.
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Thesis (M.S.)--University of Toledo, 2007.Typescript. "Submitted as partial fulfillment of the requirements for the Masters of Science Degree in Physics." "A thesis entitled"--at head of title. Bibliography: leaves 99-102.
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Zhang, Rong. "Zinc Oxide Thin Films for Dye-Sensitized Solar Cell Applications." Miami University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=miami1186016777.
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Sporar, Daniel. "Sputter Deposition of Iron Oxide and Tin Oxide Based Films and the Fabrication of Metal Alloy Based Electrodes for Solar Hydrogen Production." Connect to Online Resource-OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1183481021.
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Thesis (M.S.Ch.E.)--University of Toledo, 2007.Typescript. "Submitted as partial fulfillment of the requirements for The Master of Science degree in Chemical Engineering." Bibliography: leaves 72-77.
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Lima, Francisco Anderson de Sousa. "Application of transition-metal-oxide-based nanostructured thin films on third generation solar cells." reponame:Repositório Institucional da UFC, 2015. http://www.repositorio.ufc.br/handle/riufc/14584.
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LIMA, F. A. S. Application of transition-metal-oxide-based nanostructured thin films on third generation solar cells. 2015. 225 f. Tese (Doutorado em Ciência de Materiais) – Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2015.Submitted by Marlene Sousa (mmarlene@ufc.br) on 2015-12-17T12:45:41Z No. of bitstreams: 1 2015_tese_faslima.pdf: 24015209 bytes, checksum: a66470eb7a55b6b3c2a5e8544c6d4d32 (MD5)
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One of the greatest challenges of our time is to devise means to provide energy in a sustainable way to attend an exponentially growing demand. The energy demand is expected to grow 56% by 2040. In this context, the use of clean and sustainable sources of energy is imperative. Among these sources, solar energy is the only one which can meet the total world energy requirement even considering such large growth in demand. The solar power incident on the Earth's surface every second is equivalent to 4 trillion 100-watt light bulbs. Photovoltaic solar cells are one of several ways to harness solar energy. These cells convert solar energy directly into electricity. Commercial photovoltaic devices are already a reality, but their share of the world energy matrix is still quite small, mainly due to the high costs. Next generation photovoltaics open a number of new possibilities for photovoltaic energy applications that can potentially decrease the overall cost of energy production. Transition metal semiconductor oxides are promising materials that can be produced by low cost methods and o er interesting new features. The use of these materials in next generation photovoltaics is therefore a very promising and interesting application. In this thesis work zinc, titanium and vanadium oxides were used in next generation solar cells. Thin lms of zinc oxide were synthesized by the low cost and environmentally friendly techniques of electrodeposition and hydrothermal synthesis and applied as working electrodes in highly e cient dye sensitized solar cells (DSSCs). The lms were characterized by structural and optical techniques while the cells were tested by current vs: voltage and quantum e ciency measurements. The e ciencies of these cells were as high as 2.27% using ZnO thin lms without any post deposition treatment. Moreover, natural dyes extracted from plants of northeastern Brazil were applied as sensitizers in DSSCs assembled with commercial available TiO 2 as working electrode. The natural dyes were extracted employing very simple methods and were characterized by XPS and UPS techniques. Their band alignments were shown to be compatible with the TiO 2 as well as with the mediator electrolyte. The e ciency of DSSCs sensitized with natural dyes were as high as 1.33%. Finally, water based V 2 O 5 was used as hole transport medium (HTM) in conventional organic solar cells (OSCs) and ITO-free, plastic OSCs. The results obtained with V 2 O 5 were compared with the results obtained from cells assembled with PEDOT:PSS, which is the most used HTM. This comparison showed that the use of V 2 O 5 as HTM can lead to more e cient OSCs. The stability of these devices were evaluated by tests applying the ISOS standards ISOS-D-1, ISOS-L-1 and ISOS-O-1. A UV- lter and a protective graphene oxide (GO) layer were employed seeking to improve the stability of OSCs. The combination of both UV- lter and GO protective layer was shown to be the most e ective way to improve the stability of these devices
Um dos maiores desa os do nosso tempo e desenvolver formas para fornecer energia de forma sustent avel para atender uma demanda que cresce exponencialmente e que dever a crescer 56% at e 2040. Neste contexto, o uso de fontes limpas e sustent aveis de energia e um imperativo. Entre essas fontes, a energia solar e a unico que pode satisfazer a ne- cessidade total de energia do mundo, mesmo considerando o crescimento na demanda. A pot^encia solar incidente na superf cie da Terra a cada segundo e equivalente a 4 trilh~oes de l^ampadas de 100 watts. C elulas solares fotovoltaicas s~ao uma das v arias maneiras de aproveitar a energia solar, convertendo-a diretamente em eletricidade. Dispositivos com- erciais fotovoltaicos j a s~ao uma realidade, mas a sua participa c~ao na matriz energ etica mundial ainda e muito pequena, principalmente devido aos seus custos elevados. C elulas fotovoltaicas de nova gera c~ao abrem uma s erie de novas possibilidades para aplica c~oes de energia fotovoltaica que pode diminuir o custo total de produ c~ao de energia. Oxidos semicondutores de metais de transi c~ao s~ao materiais promissores que podem ser produzi- dos atrav es de m etodos de baixo custo e que possuem caracter sticas interessantes. Por conseguinte, o uso destes materiais em energia fotovoltaica de pr oxima gera c~ao se apre- senta com uma aplica c~ao promissora. Nesta tese de doutorado oxidos de zinco, tit^anio e van adio foram utilizados em c elulas solares de pr oxima gera c~ao. Filmes nos de oxido de zinco foram sintetizados por eletrodeposi c~ao e s ntese hidrot ermica. Os lmes foram apli- cados como eletrodos de trabalho em c elulas solares sensibilizadas por corante (DSSCS) altamente e cientes. Os lmes foram caracterizados por t ecnicas estruturais e oticas en- quanto que as c elulas foram testadas por medidas de corrente vs: voltagem e de e ci^encia qu^antica. A e ci^encia dessas c elulas atingiu 2,27% utilizando lmes nos de ZnO sem qualquer tratamento p os-deposi c~ao. Al em disso, corantes naturais extra dos de plan- tas do nordeste do Brasil foram aplicados como sensibilizadores em DSSCs montadas com TiO 2 comercial utilizado como eletrodo de trabalho. Os corantes naturais foram extra das empregando m etodos simples e foram caracterizados por espectroscopia de fotoel etrons excitados por raios X e por radia c~ao ultravioleta, XPS e UPS respectivamente. Seus alin- hamentos de banda se mostraram compat veis com o TiO 2 e com o eletrodo de regenera c~ao. A e ci^encia das DSSCs sensibilizadas com corantes naturais chegou a 1,33%. Finalmente, V 2 O 5 a base de agua foi usado como material transportador de buracos (HTM) em c elulas solares org^anicas (OSCs) convencionais e OSCs de pl astico constru das sem ITO. Os re- sultados obtidos com V 2 O 5 foram comparados com os resultados de c elulas constru das com PEDOT:PSS, que e o HTM mais utilizado. Esta compara c~ao revelou que o uso de V 2 O 5 como HTM pode levar a OSCs mais e cientes. A estabilidade destes dispositivos foi avaliada por testes aplicando os padr~oes ISOS-D-1, ISOS-L-1 e ISOS-O-1. O uso de ltros ultravioleta e de uma camada protetora de oxido de grafeno reduzido foi testado com o intuito de melhorar a estabilidade desses dispositivos. O uso de uma combina c~ao de ambos se mostrou a forma mais efetiva de melhorar a estabilidade das OSCs
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Bowers, Norman Mark. "Metal oxide nanocrystalline thin films as buffer layers in organic/ hybrid solar cells." University of Western Cape, 2019. http://hdl.handle.net/11394/7698.
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>Magister Scientiae - MScWithout reverting to encapsulation, organic bulk - heterojunction solar cells can be protected from the oxidation of the highly reactive low work function cathode metal electrode, by the deposition of metal oxide buffer layers onto an indium-tin oxide (ITO) substrate. The zinc-oxide (ZnO) or titanium dioxide (TiO2) layer can serve as an electron collecting contact. In such a case the ordering of layer deposition is inverted from the traditional layer sequencing, using an additional effect of the metal oxide layer acting as a hole blocking contact
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Macaraig, Lea Cristina De Jesus. "Studies on Surface Modified Metal Oxides Nanofibers and Thin Films for Solar Energy Conversion and Storage." Kyoto University, 2013. http://hdl.handle.net/2433/180445.
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Tahhan, Abdulla. "Energy performance enhancement of crystalline silicon solar cells." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/14503.
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The work in this thesis examines the effects of the application of oxide coatings on the performance of the single crystalline silicon photovoltaic solar cells. A variety of potential oxide materials for solar cells performance enhancement are investigated. These films are silicon oxide, titanium oxide and rare earth ion-doped gadolinium oxysulfide phosphor. This study compares the electrical characteristics, optical properties and surface chemical composition of mono-crystalline silicon cells before and after coating. The first study investigates the potential for using single and double layers of silicon oxide films produced by low-temperature Plasma Enhanced Chemical Vapour Deposition (PECVD) using tetramethylsilane as a silicon precursor and potassium permanganate oxidising agent for efficiency enhancement of solar cells at low manufacturing cost. Deposition of the films contributes to the increase of the conversion energy of the solar cells on one hand while the variety of colours obtained in this study can be of great importance for building-integrated photovoltaic application on the other hand. The obtained results demonstrated a relative enhancement of 3% in the conversion efficiency of the crystalline silicon solar cell. In the second study, the effects of using a single layer of titanium oxide and a stack of silicon oxide and titanium oxide on the performance of solar cell are demonstrated. Moreover, this study shows the use of different sputtering configurations and oxidation methods. The experimental results showed a relative enhancement of 1.6% for solar cells coated with a stack of silicon oxide/titanium oxide. In the third study, silicon cells were coated with a luminescent layer consisting of down-converting phosphor, gadolinium oxysulfide doped with erbium and terbium, and a polymeric binder of EVA using doctor-blade screen printing technique. A relative enhancement of 4.45% in the energy conversion efficiency of PV solar cell was achieved. Also, the effects of combining silicon oxide layers together with the luminescent composite are also presented in this study.
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Shantheyanda, Bojanna P. "Characterization of aluminum doped zinc oxide thin films for photovoltaic applications." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4538.
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Growing demand for clean source of energy in the recent years has increased the manufacture of solar cells for converting sun energy directly into electricity. Research has been carried out around the world to make a cheaper and more efficient solar cell technology by employing new architectural designs and developing new materials to serve as light absorbers and charge carriers. Aluminum doped Zinc Oxide thin film, a Transparent conductive Oxides (TCO) is used as a window material in the solar cell these days. Its increased stability in the reduced ambient, less expensive and more abundance make it popular among the other TCO's. It is the aim of this work to obtain a significantly low resistive ZnO:Al thin film with good transparency. Detailed electrical and materials studies is carried out on the film in order to expand knowledge and understanding. RF magnetron sputtering has been carried out at various substrate temperatures using argon, oxygen and hydrogen gases with various ratios to deposit this polycrystalline films on thermally grown SiO[sub]2 and glass wafer. The composition of the films has been determined by X-ray Photoelectron Spectroscopy and the identification of phases present have been made using X-ray diffraction experiment. Surface imaging of the film and roughness calculations are carried out using Scanning Electron Microscopy and Atomic Force Microscopy respectively. Determination of resistivity using 4-Probe technique and transparency using UV spectrophotometer were carried out as a part of electrical and optical characterization on the obtained thin film. The deposited thin films were later annealed in vacuum at various high temperatures and the change in material and electrical properties were analyzed.ID: 028916634; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2010.; Includes bibliographical references (p. 74-76).
M.S.
Masters
School of Electrical Engineering and Computer Science
Engineering and Computer Science
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Carreras, Seguí Paz. "Doped and multi-compound ZnO-based transparent conducting oxides for silicon thin film solar cells." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/109157.
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The objective of the present work is to provide a better understanding of magnetron sputtered transparent conducting oxides based on ZnO in order to use them as electrodes in thin film silicon solar cells at the Grup d'Energia Solar of the Universitat de Barcelona. This thesis presents the properties of magnetron sputtered aluminium and gallium doped ZnO as well as the properties of multi-compound materials deposited by the co-sputtering of zinc oxide and indium tin oxide. The application of ZnO based transparent conducting oxides to the back reflector of pin amorphous solar cells is also discussed.
A set of aluminium doped zinc oxide layers were deposited under different substrate temperature and discharge power. The structural, electrical and optical properties were characterised and discussed. The higher substrate temperatures and discharge powers used during deposition led to highly transparent layers in the visible range with lower resistivities. The polycrystalline layers were oriented with the c-axis perpendicular to the substrate surface and the crystalline quality of the layers improved at higher temperatures and powers. A remarkable increase in mobility was found for temperatures above 300°C and the carrier concentration also rose with temperature reaching 3.71x1020 cm-3 at 420°C. The most remarkable feature found at higher deposition power was the increase in deposition rate (from 0.9 to 9 nm/min).
By means of a high temperature (650°C) annealing process under a capping layer of silicon or alumina, the mobility of aluminium doped zinc oxide layers was considerably raised achieving 68.5 cm2V-1s-1. This process led also to more transparent layers in the near infrared as well as in the ultraviolet part of the spectrum.
Gallium doped zinc oxide films were deposited in order to investigate the suitability of gallium as a dopant in zinc oxide layers. Highly transparent layers with higher carrier concentrations but lower mobilities compared to aluminium doped zinc oxide were obtained. The dependence of the layer properties on the pressure, doping concentration, substrate temperature and oxygen volume concentration during deposition were studied in order to find the adequate layer to be applied as electrode in thin film solar cells. 4 wt.% Ga2O3 doping concentration was found to be optimal for the production of highly conductive ZnO:Ga layers with a high band gap energy. The incorporation of oxygen gas during the sputter deposition led to more transparent layers at wavelengths longer than 1100 nm, but was found to be detrimental for the electrical properties of the studied layers.
By means of co-sputtering, a set of multi-compound layers formed by Zn-In-Sn-O were deposited and carefully characterised. The resulting layers were studied as a function of the Zn content ratio, which varied between 17.1 to 67.3%. The layers were amorphous in nature but presented embedded nanometric crystals. The incorporation of Zn cations into an indium tin oxide matrix favoured the transmittance but did not modify the mobility. The carrier concentration was found to decrease resulting in an increase in resistivity. The electronic band structure was investigated by means of photoelectron spectroscopy. The measurements showed that, with an increase in Zn concentration, the oxygen vacancy concentration of the surface increased resulting in a degenerately n-doped surface layer. The work function of the material was determined by low intensity X-ray photoelectron spectroscopy and the values varied between 4.7 and 4.3 eV with the variation of Zn content.
The final experiments were focussed on the application of ZnO layers in the back reflectors of pin amorphous silicon solar cells. Trials were performed onto pin structures deposited at T-Solar Global SA and the Universitat de Barcelona.
The cells deposited at T-Solar were long exposed to air before a back reflector could be deposited and evidence for the formation of a thin silicon oxide layer at the interface was obtained. The oxide layer was removed using acid etching in dilute HF, but an analysis by X-ray photoelectron spectroscopy showed that the cleaning step resulted in an important amount of carbon contamination on the surface. Both, the silicon oxide and the carbon layer led to devices with S-shaped J-V curves. Later, the n-type interface was protected by a thin ZnO:Al layer at T-Solar to avoid oxidation during transportation. However, the existence of this thin ZnO:Al protective layer determined the growth of the subsequently deposited layers. Thus, the deposition of ZnO layers under different conditions led to similar results. Finally, different back reflectors were tried over the solar cells fabricated at UB. Aluminium and gallium doped zinc oxide layers were deposited on amorphous silicon pin structures, and a clear improvement in performance with respect to devices with only a metal layer as back reflector was observed. Similar performances were observed when Ga doped ZnO or Al doped ZnO was used in the back reflector. It showed that both gallium and aluminium were suitable dopants for the ZnO to be applied in the back reflector.L'objectiu d'aquest treball rau en l'estudi i optimització dels òxids conductors transparents basats en l'òxid de zinc. Aquests materials, que s'han dipositat mitjançant polvorització catòdica magnetró, es van estudiar amb la finalitat d'emprar-los com elèctrodes en cèl•lules solars de silici en capa prima al Grup d'Energia Solar de la Universitat de Barcelona. En aquesta tesi es presenten les propietats de l'òxid de zinc dopat amb alumini o amb gal•li, així com les propietats de multi-compostos dipositats a partir de la co-polvorització catòdica d'òxid de zinc i d'òxid d'indi dopat amb estany. També es discuteix l'aplicació d'òxids conductors transparents basats en l'òxid de zinc al reflector posterior de cèl•lules solars de silici amorf amb estructura tipus pin. S’ha trobat que l’òxid de zinc dopat amb alumini, a altes temperatures de substrat i altes potències, presenta una elevada transmitància òptica i una baixa resistivitat. La mobilitat de les capes augmentà considerablement fins assolir 68.5 cm2V-1s-1 mitjançant l'aplicació de tractaments tèrmics a alta temperatura previ dipòsit d'una capa protectora de silici amorf o d'alúmina. Pel cas de l'òxid de zinc dopat amb gal•li s'han obtingut una sèrie de capes altament transparents i amb concentracions de portadors superiors, però amb mobilitats inferiors que les de capes dopades amb alumini. Mitjançant co-polvorització d’òxid de zinc i òxid d’indi dopat amb estany s’han obtingut capes amorfes del multi-compost Zn-In-Sn-O amb un contingut de zinc que varia entre el 17.1 i el 67.3%. La incorporació del zinc a l'òxid d'indi dopat amb estany afavoreix l'increment de la transmitància, sense que la mobilitat de les capes es vegi afectada. En canvi, la concentració de portadors disminueix amb la incorporació de Zn. Comparant l'ús del gal•li i de l'alumini com a dopants de l'òxid de zinc del reflector posterior de cèl•lules de silici amorf tipus pin, s'ha observat una gran similitud en el comportament dels dispositius. Això ens ha portat a la conclusió que ambdós materials són adients per ser emprats com a reflectors posteriors.
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Liu, Hanxiao. "Studies of efficient and stable organic solar cells based on aluminum-doped zine oxide transparent electrode." HKBU Institutional Repository, 2014. https://repository.hkbu.edu.hk/etd_oa/34.
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Organic solar cells (OSCs) have attracted significant attention due to their potential of large area solution fabrication capability at low-cost. For bulk heterojunction (BHJ) OSCs, a thin film of transparent conducting indium tin oxide (ITO), coated on glass or flexible plastic substrate, is widely used as a front electrode. However, indium is not abundant on Earth. Its price has increased continuously over the past 10 years and will likely become an obstacle for the commercialization of OSCs at low cost. Aluminum-doped zinc oxide (AZO) is a promising ITO alternative due to its advantages of high electric conductivity, optical transparency, non-toxicity and low cost. However, reports on OSCs using AZO electrode are quite limited, due to the relatively lower power conversion efficiency (PCE) of AZO-based OCSs as compared to that of ITO-based OCSs. This work focused on studies of high performance AZO-based OSCs through AZO surface modification, absorption enhancement and process optimization. The optical and electronic properties of AZO film including transmittance, sheet resistance, surface morphology and surface work function were characterized. AZO-based OSCs with conventional and inverted structures were fabricated. It was found that AZO-based OSCs with inverted structure demonstrated superior performance than the ones with conventional structure. The inverted structure avoids the use of acidic PEDOT:PSS hole transporting layer, allows the improving of the absorbance of the OSCs and therefore its efficiency. An AZO front transparent cathode was used for application in high performance inverted BHJ OSCs. The photoactive layer consisted a blend of poly[[4,8-bis[(2- ethylhexyl)oxy] benzo [1,2-b:4,5-b'] dithiophene-2,6- diyl][3-fluoro- 2-[(2-ethylhexyl) carbonyl]thieno[3,4-b]thiophenediyl]](PTB7):3'H-Cyclopropa[8,25][5,6]fullerene- C70- D5h(6)-3'-butanoicacid, 3'-phenyl-, methyl ester (PC70BM). A structurally identical control OSC having an ITO front cathode was also fabricated for comparison studies. The structure of OSCs was optimized to achieving absorption enhancement in the active layer. AZO and ITO were modified with a 10 nm thick solution-processed ZnO interlayer to facilitate the efficient electron extraction. The results revealed that bilayer AZO/ZnO and the ITO/ZnO cathodes possess similar electron extraction property. AZO layer has a transparency cutoff at wavelength < 380 nm, results in a slight decrease in the short-circuit current density (JSC). However, the decrease in JSC is very small because the main energy of solar irradiation falls in the spectrum with wavelength > 380 nm. It shows that AZO-based OSCs have a promising PCE of 6.15%, which is slightly lower than that of a control ITO-based OSC (6.57%). AZO-based OSCs, however, demonstrate an obvious enhancement in the stability under an ultraviolet (UV)-assisted acceleration aging test. The significant enhancement in the stability of AZO-based OSCs arises from the tailored absorption of AZO electrode in wavelength < 380 nm, which serves as a UV filter to inhibit an inevitable degradation process in ITO-based OSCs due to the UV irradiation. In order to further investigate the degradation mechanism of OSCs under UV exposure, the change in charge collection characteristics of the OSCs made with ITO/ZnO and AZO/ZnO front cathode before and after UV exposure was examined. It was found that there was an obvious decrease in the charge extraction efficiency of ITO-based OSCs after UV exposure, while there was no observable change in the charge extraction efficiency of OSCs made with AZO/ZnO cathode under the same acceleration aging test. This work demonstrates that AZO is a suitable ITO alternative for application in OSCs, offering an improved device stability, comparable PCE and cell fabrication processes with an attractive commercial potential.
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Chou, Tammy Ping-Chun. "Effects of the nanostructure and the chemistry of various oxide electrodes on the overall performance of dye-sensitized solar cells /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/10580.
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Matsumura, Masashi. "Synthesis, electrical properties, and optical characterization of hybrid zinc oxide/polymer thin films and nanostructures." Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2009r/matsumura.pdf.
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Thesis (Ph. D.)--University of Alabama at Birmingham, 2007.Title from PDF t.p. (viewed Feb. 3, 2010). Additional advisors: Derrick R. Dean, Sergey B. Mirov, Sergey Vyazovkin, Mary Ellen Zvanut. Includes bibliographical references (p. 122-145).
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Möllmann, Alexander [Verfasser]. "Nanostructured Metal Oxide Thin Films as Electron Transport Material for Inorganic-Organic Hybrid Perovskite Solar Cells / Alexander Möllmann." München : Verlag Dr. Hut, 2020. http://d-nb.info/1219478067/34.
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Zou, Elva Xin. "Sol-gel processed zinc oxide for third generation photovoltaics." Thesis, University of Oxford, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.559838.
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This thesis presents an experimental study of the incorporation and optimization of sol-gel processed aluminum doped zinc oxide (AZO) thin films in solar cell devices. I first optimized the optoelectronic properties of AZO thin films by manipulating the dopant incorporation, choice of precursor chemicals and post deposition anneal treatments. Results showed that improved performance could be attributed to several factors, including improved charge carrier concentration, mobility and conductivity. AZO thin films with transmittance of over 90% and resistivity values of the order of 10-2 Ω•cm have been achieved. I also demonstrated the successful application of these AZO thin films in organic photovoltaics (OPV), to serve as an alternative to ITO electrodes. I demonstrated greater than 2-fold improvement in device efficiency through the modification of the front contact/polymer interface using zinc oxide buffer layers. This improved the charge selectivity of the electrodes and energy level alignment at the interface while reducing the recombination of separated charges and the device's series resistance. Finally, I showed that the efficiency of inverted ZnO/PbS quantum dots solar cells can be enhanced by optimizing the p-type PbS thickness, UV treating the n-type ZnO layer and exposing the devices in the dark to nitrogen. Both ZnO and AZO systems were studied, and efficiency enhancement were demonstrated for a range of Al content from 0 to O.4at.%.
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Shih, Jeanne-Louise. "Zinc oxide-silicon heterojunction solar cells by sputtering." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112583.
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Heterojunctions of n-ZnO/p-Si solar cells were fabricated by RF sputtering ZnO:Al onto boron-doped (100) silicon (Si) substrates. Zinc Oxide (ZnO) films were also deposited onto soda lime glass for electrical measurements. Sheet resistance measurements were performed with a four-point-probe on the glass samples. Values for samples evacuated for 14 hours prior to deposition increased from 7.9 to 10.17 and 11.5 O/□ for 40 W, 120 and 160 W in RF power respectively. In contrast, those evacuated for 2 hours started with a higher value of 22.5 O/□, and decreased down to 7.6 and 5.8 O/□. Vacuum annealing was performed for both the glass and the Si samples. Current-voltage measurements were performed on the ZnO/Si junctions in the dark and under illumination. Parameters such as open-circuit voltage, Voc; short-circuit current, Isc; fill factor, FF; and efficiency, eta were determined. A maximum efficiency of 0.25% among all samples was produced, with an I sc of 2.16 mA, Voc of 0.31V and a FF of 0.37. This was a sample fabricated at an RF power of 80 W. Efficiency was found to decline with vacuum annealing. Furthermore, interfacial state density calculated based on capacitance-voltage measurements showed an increase in the value with vacuum annealing. The results found suggest that the interface states may be due to an interdiffusion of atoms, possibly those of Zn into the Si surface. The Electron Beam Induced Current (EBIC) method was used to determine diffusion length to be at a value ∼40--80 mum and therefore a minority carrier lifetime calculated of 3 musec. It was also used to determine the surface recombination velocity (SRV) of the fractured surface of the Si bulk from the fabricated solar cells. An SRV of ∼500 cm/sec was determined from the fractured Si surface, at a point located at 30 and 20 mum away from the junction interface.
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Payrer, Elisabeth L. "Light up-conversion in rare earth doped thin films : synthesis, characterization, luminescence and prospects for solar cell application." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI008.
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Le phénomène d’up-conversion de photon (UpC) permet de générer de la lumière à longueurs d’onde plus courtes que la longueur d’onde d’excitation. Dans cette recherche, la synthese de couches minces dopées avec des ions de terres rares (RE3+) optiquement actifs, leurs caractérisations structurales, ainsi que leurs propriétés optiques et de photoluminescentes ont été étudiées. Les couches ont été élaborées par deux voies de dépôt de couche sur du silicium et des substrats transparents: tout d’abord, un dépôt chimique organométallique en phase vapeur (LI-MOCVD, AA-MOCVD) est utilisé pour le dépôt des couches minces de YF3 et Y2O3 co-dopées Er/Yb. Il est démontré que l’émission d’UpC de Er3+ avec une excitation à 972 nm est influencée par le réseau hôte. Par ailleurs, le traitement sol-gel, une technique chimique par voie humide, est utilisé pour la fabrication de couches minces Y2O3, SiO2 et TiO2 co-dopées Er/Yb par spin-coating. Une optimisation de l’´emission de lumière par UpC a été atteinte grâce à l’ajustement de la concentration de RE et de la température de traitement thermique. De plus, une approche différente a été étudiée pour atteindre une émission UpC renforcée : l’utilisation de microcavités diélectriques de Fabry-Pérot obtenues par sol-gel, constitués d’un empilement de couches de silice et d’oxyde de titane, avec Er/Yb:Y2O3 comme couche de cavité. Le but de ce travail est de répondre aux questions suivantes: comment la nature du réseau hôte et le niveau de dopage influencent l’émission radiative de l’Er3+? Quelles sont les conditions pour un bon matériau d’UpC et ses limites? Nous incluons également une discussion sur les perspectives d’une application possible d’une couche d’UpC dans un dispositif de cellule solaire, qui pourrait améliorer la réponse dans l’infrarougePhoton up-conversion (UpC) allows the generation of light of shorter wavelengths compared to the excitation wavelength. In this work the synthesis of thin films doped with optically active rare earth (RE3+) ions, their structural characterization, as well the optical and photoluminescence properties are highlighted. The emphasis lies on two different routes of film deposition on silicon and transparent substrates: first, metalorganic chemical vapor deposition (LI-MOCVD, AA-MOCVD) is introduced for the deposition of Er/Yb-doped YF3 and Y2O3 films and it is demonstrated, how the UpC emission of Er3+ upon 972 nm excitation is influenced by the host lattice. Secondly, sol-gel processing, a wet-chemical technique, is used for the fabrication of Er/Yb-doped Y2O3, SiO2 and TiO2 thin films by spin-coating. Optimization of the up-converted light emission was achieved through adjusting the RE concentration and the processing temperature. Moreover, in a different approach for achieving an enhanced UpC emission, sol-gel derived Fabry-Pérot dielectric microcavities, consisting of a multilayer stack of silica and titania layers and Er/Yb: Y2O3 as the cavity layer, are investigated. The aim of this work is to address the questions, how does the nature of the host lattice and doping level influence the radiative emission in Er3+, what are the requirements for a good upconverter material and what are the limitations? We also include a discussion of the application of an upconverter to a solar cell device, which may debatably enhance the response in the infrared
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Haynes, Keith M. "Molecules and Materials for Excitonic Solar Cells Using P-type Metal Oxide Semiconductors." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804970/.
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This dissertation has two intersecting foci; firstly, the discovery of a new methodology for the growth of high surface area cuprous oxide (Cu2O) substrates. Secondly, the synthesis and characterization of electron-accepting molecules, and their incorporation into excitonic solar cells (XSCs) using the Cu2O substrates as electrodes. Increasing the surface area of the semiconductor creates more locations for charge transfer to occur thus increasing the overall efficiency of the device. Zinc oxide (ZnO) has been widely studied, and can be easily grown into many different films with high surface area morphologies. The ZnO films serve as sacrificial templates that allow us to electrochemically grow new semiconductors with the same high surface area morphologies but composed of a material having more desirable electronic properties. A polymer can be applied over the surface of the ZnO nanorod films before etching the ZnO with a weak acid, thereby leaving a polymer nanopore membrane. Cathodic electrodeposition of Cu2O into the membrane nanopores gives Cu2O nanorods. Electron-accepting dyes are designed with tethers that allow for direct attachment to metal oxide semiconductors. After soaking, the semiconductor is coated with a monolayer of a dye and then the coated semiconductor films were made into various dye-sensitized solar cells (DSCs). These cells were studied to determine the electron transport properties at the semiconductor/sensitizer/electrolyte interface.
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Arnou, Panagiota. "Solution processing of thin films for solar cell applications : CuIn(S,Se)2, Cu(In,Ga)(S,Se)2 and ZnO:Al." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/23224.
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Cu(In,Ga)(Se,S)2 (CIGS) solar cells have attracted a lot of attention due to their high performance and the prospect for lower manufacturing costs over conventional crystalline silicon solar cells. All recent record efficiency CIGS absorbers have been deposited using vacuum processing which introduces high manufacturing costs. CIGS can also be compatible with low cost, atmospheric processing which can significantly reduce manufacturing costs. Recently, there has been some progress in developing atmospheric solution-based processes for CIGS. Among different solution approaches, deposition of molecular precursors can be advantageous in terms of simplicity and straightforward compositional control. Nonetheless, the developed methodologies involve highly toxic reagents or large impurity content in the device, limiting the potential for commercialisation. This thesis describes the development of a novel solution-based approach for the deposition of CIGS absorber layers. Metal chalcogenides are used as the starting precursors, which are free from detrimental impurities. These compounds contain strong covalent bonds and, consequently, they are insoluble in common solvents. Until recently, hydrazine, which is highly toxic and explosive, was the only solvent to effectively dissolve these types of precursors, limiting the feasibility of this approach for industrial applications. In this work, metal chalcogenides are dissolved in a safer solvent combination of 1,2-ethanedithiol and 1,2-ethylenediamine, completely eliminating hydrazine from the process. By using this solvent system, optically transparent solutions are formed which exhibit long-term stability. The precursor solutions are decomposed cleanly and they are converted to single phase CIGS upon selenisation. CuIn(S,Se)2 solar cells with power conversion efficiencies up to 8.0% were successfully fabricated by spray depositing the precursor solution, followed by a selenisation step. This progress has been made by continuously optimising the deposition, drying, and especially the selenisation configuration. Among other parameters, the working pressure during selenisation was found to have a dramatic effect on the material crystalline quality. Rapid thermal processing was also explored as an alternative selenisation configuration to tube furnace annealing and it was shown to improve the back contact/absorber interface. It has been demonstrated that Ga can easily be incorporated in the absorber for band-gap tuning and, consequently, for VOC enhancement of the solar cells. The structural properties of the films were investigated with Ga content, as well as the opto-electronic characteristics of the corresponding solar cells. The band-gap of the material was conveniently varied by simply adjusting the precursor ratio, allowing for fine compositional control. By using this technique, Cu(In,Ga)(Se,S)2 solar cells with conversion efficiencies of up to 9.8% were obtained. The solar cell performance in this work is limited by the porosity of the absorber and the back contact quality. Despite a significant improvement during the course of this work, the remaining porosity of the absorber causes selenium to diffuse towards the back forming a thick MoSe2 layer and causing a high series resistance in the device. A low cost, solution-based technique was also developed for the deposition of aluminium-doped zinc oxide films that can be used as the transparent conductive oxide layer in thin film solar cells. This methodology involves the use of an ultrasonic spray pyrolysis system, which is a very versatile and easily controlled deposition technique. Although the presence of oxygen makes the film closer to stoichiometric (fewer oxygen vacancies) good electronic and optical properties have been obtained by process optimisation. Films deposited with optimum conditions exhibited a sheet resistance of 23 Ω/sq, which can be further reduced by increasing the thickness with minimal transmittance losses. The simplicity, low toxicity and straightforward control make the proposed methodologies extremely potential for low cost and scalable deposition of thin film solar cells.
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Heinemann, Marc Daniel [Verfasser], Bernd [Akademischer Betreuer] Rech, Michael [Gutachter] Powalla, Bernd [Gutachter] Rech, and Susan [Gutachter] Schorr. "CIGSe superstrate solar cells : growth and characterization of CIGSe thin films on transparent conductive oxides / Marc Daniel Heinemann ; Gutachter: Michael Powalla, Bernd Rech, Susan Schorr ; Betreuer: Bernd Rech." Berlin : Technische Universität Berlin, 2016. http://d-nb.info/115618021X/34.
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Catto, Ariadne Cristina [UNESP]. "Filmes finos de ZnO como óxidos condutores transparentes aplicados à células solares." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/99710.
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catto_ac_me_bauru.pdf: 1118478 bytes, checksum: 91862c7c0ab732aaf99e455ed18b8bb1 (MD5)As alterações climáticas, em grande parte, proveniente da emissão de CO2 derivado da queima de combustíveis fósseis para produção de energia, têm incentivado a pesquisa e o desenvolvimento de novas fontes alternativas de energia menos pulentes e que produzam pouco impacto ambiental. Uma das alternativas energéticas mais promissoras é a energia gerada pelo sol, principalmente em países onde há um alto índice de incidência de radiação solar. O óxido de zinco (ZnO) apresenta transmitância óptica na região do visível acima de 80% e baixa resistividade elétrica. Este material tem sido estudado como candidato para substituir o In2O3:Sn (ITO) em aplicações como eletrodos de células solares, pois além de ser economicamente viável, é atóxico e possui alta estabilidade química. Neste trabalho filmes finos de ZnO puro foram depositados pelas técnicas de spin, dip-coating e evaporação por feixe de elétrons (EBE). As resinas precursoras de ZnO foram sintetizadas pelo método dos precursores poliméricos utilizando diferentes precursores de Zn (acetato, óxido ou nitrato de zinco), com a finalidade de investigar as propriedades estruturais e ópticas dos filmes finos de ZnO preparado por diferentes técnicas e diferentes precursores. Os filmes foram caracterizados por difração de raios-X (DRX), medidas de espectro na região do UV-vi e microscopia de força atômica (AFM). Todas as amostras obtidas através das diferentes técnicas de deposição apresentaram alto grau de transmitância óptica (80%) e o mesmo valor de energia de gap (3,28 e V). Também foram obtidas amostras na forma de pó, sintetizado com os três diferentes precursores, visando um estudo aprofundado da influência do precursor utilizado nas propriedades do material. As amostras foram caracterizadas por difração de raios X, análises...
Climate changes are mainly due to the increasing CO2 atmospheric concentration caused by the burning of fossils fuels. In this context, researh and development of alternative sources of renewable energy have been encouraged for energy production. One of most promising alternative for energy production is Solar Energy, especially in countries with high incidence of solar radiation. Zinc oxide thin films usually have high transmittance in the visible range and low resistivity. This material has been studied as a candidate to replace In2O3:Sn(ITO) in applications such as electrodes in solar cells due of the righ cost of indium and its limited availability. Furthermore ZnO is chemically stable and non-toxic. In this work undoped zinc oxide thin films were deposited by the techniques of spin-coating, dip-coating and Electron beam evaporation (EBE). Resins of ZnO were synthesized by the polymeric precursor method using different zinc precursors (zinc acetate, oxide or nitrate) in order to study the structural and optical properties of thin films prepared by different techniques and using different precursors. The prepared samples were characterized by X-ray diffraction measurements (XRD), UV-vis spectra, and atomic force microscopy (AFM). All samples prepared by different deposition techiniques present transmition larger than 80% in the visble range and band gap of 3,28 eV. Also were obtained powder or ZnO synthesized using three different precursor in order to study the influence of precursor utilized in properties of material. The powder were characterized by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, field emission scanning microscopy (FE-SEM), thermogravimetry (TG) and differential thermal analysis (DTA). Through these characterization techniques it was showed that the polymeric precursor... (Complete abstract click electronic access below)
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Chistiakova, Ganna [Verfasser], Bernd [Akademischer Betreuer] Rech, Klaus [Gutachter] Lips, Uwe [Gutachter] Rau, and Bernd [Gutachter] Rech. "Development of metal oxide thin films as carrier selective contacts for silicon heterojunction solar cells / Ganna Chistiakova ; Gutachter: Klaus Lips, Uwe Rau, Bernd Rech ; Betreuer: Bernd Rech." Berlin : Technische Universität Berlin, 2020. http://d-nb.info/1210998440/34.
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Catto, Ariadne Cristina. "Filmes finos de ZnO como óxidos condutores transparentes aplicados à células solares /." Bauru : [s.n.], 2012. http://hdl.handle.net/11449/99710.
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Orientador: Paulo Noronha Lisboa FilhoBanca: Caue Ribeiro de Oliveira
Banca: Cyro Ketzer Saul
O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter insitucional e integra as atividades de pesquisa em materiais de diversos campi
Resumo: As alterações climáticas, em grande parte, proveniente da emissão de CO2 derivado da queima de combustíveis fósseis para produção de energia, têm incentivado a pesquisa e o desenvolvimento de novas fontes alternativas de energia menos pulentes e que produzam pouco impacto ambiental. Uma das alternativas energéticas mais promissoras é a energia gerada pelo sol, principalmente em países onde há um alto índice de incidência de radiação solar. O óxido de zinco (ZnO) apresenta transmitância óptica na região do visível acima de 80% e baixa resistividade elétrica. Este material tem sido estudado como candidato para substituir o In2O3:Sn (ITO) em aplicações como eletrodos de células solares, pois além de ser economicamente viável, é atóxico e possui alta estabilidade química. Neste trabalho filmes finos de ZnO puro foram depositados pelas técnicas de spin, dip-coating e evaporação por feixe de elétrons (EBE). As resinas precursoras de ZnO foram sintetizadas pelo método dos precursores poliméricos utilizando diferentes precursores de Zn (acetato, óxido ou nitrato de zinco), com a finalidade de investigar as propriedades estruturais e ópticas dos filmes finos de ZnO preparado por diferentes técnicas e diferentes precursores. Os filmes foram caracterizados por difração de raios-X (DRX), medidas de espectro na região do UV-vi e microscopia de força atômica (AFM). Todas as amostras obtidas através das diferentes técnicas de deposição apresentaram alto grau de transmitância óptica (80%) e o mesmo valor de energia de gap (3,28 e V). Também foram obtidas amostras na forma de pó, sintetizado com os três diferentes precursores, visando um estudo aprofundado da influência do precursor utilizado nas propriedades do material. As amostras foram caracterizadas por difração de raios X, análises... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Climate changes are mainly due to the increasing CO2 atmospheric concentration caused by the burning of fossils fuels. In this context, researh and development of alternative sources of renewable energy have been encouraged for energy production. One of most promising alternative for energy production is Solar Energy, especially in countries with high incidence of solar radiation. Zinc oxide thin films usually have high transmittance in the visible range and low resistivity. This material has been studied as a candidate to replace In2O3:Sn(ITO) in applications such as electrodes in solar cells due of the righ cost of indium and its limited availability. Furthermore ZnO is chemically stable and non-toxic. In this work undoped zinc oxide thin films were deposited by the techniques of spin-coating, dip-coating and Electron beam evaporation (EBE). Resins of ZnO were synthesized by the polymeric precursor method using different zinc precursors (zinc acetate, oxide or nitrate) in order to study the structural and optical properties of thin films prepared by different techniques and using different precursors. The prepared samples were characterized by X-ray diffraction measurements (XRD), UV-vis spectra, and atomic force microscopy (AFM). All samples prepared by different deposition techiniques present transmition larger than 80% in the visble range and band gap of 3,28 eV. Also were obtained powder or ZnO synthesized using three different precursor in order to study the influence of precursor utilized in properties of material. The powder were characterized by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, field emission scanning microscopy (FE-SEM), thermogravimetry (TG) and differential thermal analysis (DTA). Through these characterization techniques it was showed that the polymeric precursor... (Complete abstract click electronic access below)
Mestre
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Diyaf, Adel G. Abdussalam. "Flexible thin films on textiles for solar cells." Thesis, Heriot-Watt University, 2014. http://hdl.handle.net/10399/2808.
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In recent years, there has been an increase in studies about developing photovoltaic fabrics which can be used in different textile and clothing applications. The flexibility of the solar cells could be useful in many applications, for example providing power for small portable electronic devices such as personal digital assistants or on a larger scale for sunshades and canopies. In this work, we have taken the direct approach to deposit amorphous silicon cells directly onto fabrics. To achieve that, we have studied approaches to obtaining flexible conductive surfaces on polyester fabrics by using a double layer of metal and commercially available conductive polymer. Then both single and stacked metal contact layers and thin amorphous silicon films were built on glass and flexible substrates for optical and electric characterisation. It was shown by bending tests that the conductive fabrics retain both flexibility and electrical conductivity. Finally, complete n-i-p single junction a-Si:H cells were fabricated on different types of substrates such as glasses, polyester fabric and polytetrafluoroethylene fabric (PTFE). Several challenging aspects related to the fabrication and characterisation of solar cells on fabrics are highlighted. Cells on woven fabrics were shown to be active photovoltaic devices though with lower response than equivalent cells on rigid glass substrates.
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Silva, Luciane Janice Venturini da. "Produção e caracterização de filmes finos de ZnO." Universidade Federal de Santa Maria, 2010. http://repositorio.ufsm.br/handle/1/9210.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorAmong the semiconducting oxides, ZnO has received considerable attention as a promising material for several applications in optoelectronic devices due to its high optical transparency in the visible range and good electrical conductivity achieved by doping with suitable elements. The present work, part developed in the Laboratório de Magnetismo e Materiais Magnéticos Nanoestruturados (UNIPAMPA/BAGÉ) and part in the Laboratório de Magnetismo e Materiais Magnéticos (UFSM), aimed mainly the development of an experimental procedure of ZnO thin films potentiostatic electrodeposition using 0.1 M aqueous solution of zinc nitrate seeking potential applications in solar cells. The electrodeposition technique is the growth of certain material on a solid substrate by electrochemical reactions and emerges as an alternative to traditional techniques (sputtering, sol-gel, spray pyrolysis) production of thin films. Besides being relatively easy to implement and has low production cost. The ZnO thin films were deposited on Au (111) substrates, obtained from commercial CD-Rs (CDtrodos). Voltammetry technique was used for the electrochemical processes involved analysis and to establish suitable areas of potential for films growth. ZnO deposits were characterized by X-ray diffraction and atomic force microscopy (AFM) techniques.
Dentre os óxidos semicondutores, o ZnO tem recebido considerável atenção como um material promissor para diversas aplicações em dispositivos opto-eletrônicos devido a sua alta transparênciaóptica na faixa do visível e boa condutividade elétrica alcançada por dopagem com elementos adequados. O presente trabalho, desenvolvido parte no Laboratório de Magnetismo e Materiais Magnéticos Nanoestruturados (UNIPAMPA/BAGÉ) e parte no Laboratório de Magnetismo e Materiais Magnéticos (UFSM), teve como objetivo principal o desenvolvimento de um procedimento experimental de eletrodeposição potenciostática de filmes finos de ZnO visando possíveis aplicações em células solares, utilizando-se 0:1M de solução aquosa de nitrato de zinco. A técnica de eletrodeposição consiste no crescimento de determinado material sobre um substrato sólido através de reações eletroquímicas e surge como uma alternativa às técnicas tradicionais (sputtering, sol-gel, spray-pirólise) de produção de filmes finos. Além de ser relativamente de fácil implementação e tem baixo custo de produção. Os filmes finos de ZnO foram depositados sobre substratos de Au (111), obtidos a partir de CD-Rs comerciais (CDtrodos). Utilizou-se a técnica de voltametria para analise dos processos eletroquímicos envolvidos e para estabelecer as regiões de potenciais adequadas para crescimento dos filmes. Os depósitos de ZnO foram caracterizados utilizando as técnicas de difração de raios-X e microscopia de força atômica (AFM).
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Teran-Escobar, Gerardo, David M. Tanenbaum, Eszter Voroshazi, Martin Hermenau, Kion Norrman, Matthew T. Lloyd, Yulia Galagan, et al. "On the stability of a variety of organic photovoltaic devices by IPCE and in situ IPCE analyses – the ISOS-3 inter-laboratory collaboration." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-139279.
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This work is part of the inter-laboratory collaboration to study the stability of seven distinct sets of state-of-the-art organic photovoltaic (OPV) devices prepared by leading research laboratories. All devices have been shipped to and degraded at RISØ-DTU up to 1830 hours in accordance with established ISOS-3 protocols under defined illumination conditions. In this work, we apply the Incident Photon-to-Electron Conversion Efficiency (IPCE) and the in situ IPCE techniques to determine the relation between solar cell performance and solar cell stability. Different ageing conditions were considered: accelerated full sun simulation, low level indoor fluorescent lighting and dark storage. The devices were also monitored under conditions of ambient and inert (N2) atmospheres, which allows for the identification of the solar cell materials more susceptible to degradation by ambient air (oxygen and moisture). The different OPVs configurations permitted the study of the intrinsic stability of the devices depending on: two different ITO-replacement alternatives, two different hole extraction layers (PEDOT:PSS and MoO3), and two different P3HT-based polymers. The response of un-encapsulated devices to ambient atmosphere offered insight into the importance of moisture in solar cell performance. Our results demonstrate that the IPCE and the in situ IPCE techniques are valuable analytical methods to understand device degradation and solar cell lifetimeDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Flammersberger, Hendrik. "Experimental study of Cu2ZnSnS4 thin films for solar cells." Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-139198.
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Cu2ZnSnS4 (CZTS) is a semiconductor with a direct band gap of about 1,5 eV and anabsorption coefficient of 10^4 cm^-1, and is for this reason a potential thin film solarcell material. Demonstrated efficiencies of up to 6,8% as well as use of cheap andabundant elements make CZTS a promising alternative to current solar cells.The aim of this study was to fabricate and characterize CZTS films and to evaluatetheir performance in complete solar cells. For the fabrication of CZTS we applied atwo-step process consisting of co-sputtering of the metal or metal-sulphurprecursors, and subsequent sulphurization by heating at 520°C in sulphur atmosphereusing sealed quartz ampoules.The work included a systematic comparison of the influence of composition on qualityand efficiency of CZTS solar cells. For this purpose films with various metallic ratioswere produced. The results show that the composition has a major impact on theefficiency of the solar cells in these experiments. Especially zinc-rich, copper-poor andtin-rich films proved to be suitable for good cells. The worst results were received forzinc-poor films. An increase in efficiency with zinc content has been reportedpreviously and was confirmed in this study. This can be explained by segregation ofdifferent secondary phases for off-stochiometric compositions. According to thephase diagram, zinc-poor films segregate mainly copper sulfide and copper tin sulfidecompounds which are conductive and therefore detrimental for the solar cell. Zincsulfide, that is supposed to be present in the other regions of the phase diagramexamined in this study, could be comparatively harmless as this secondary phase isonly isolating and by this ’just’ reduces the active area. This is less disadvantageousthan the shunting that can be caused by copper sulfides. Contrary to the efficiencyresults, metal composition had no major impact on the morphology.A comparison of the composition before and after the sulphurization revealed thatmetal precursors showed higher tin losses than sulphur containing precursors. Apossible explanations for this was given.Another central point of this work was the examination of the influence of sulphur inthe precursor. Less need of additional sulphur in the film might lead to better materialquality. This is based on the assumption that the film is subjected to less diffusion ofthe elements and so to less dramatic changes within the film, which might result infewer voids and defects. However, our experiments could find only a weak trend thatsulphur in the precursor increases the performance of the solar cells; concerningmorphology it was observed that more compact films with smaller grains developfrom metal-sulphur-precursors.The best efficiency measured within this work was 3,2%.
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Salomé, Pedro Manuel Parracho. "Chalcogenide thin films for solar cells: growth and properties." Doctoral thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/3723.
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Doutoramento em FísicaThin film solar cells have in recent years gained market quota against traditional silicon photovoltaic panels. These developments were in a large part due to CdTe solar panels on whose development started earlier than their competitors. Panels based on Cu(In,Ga)Se2 (CIGS), despite being more efficient in a laboratory and industrial scale than the CdTe ones, still need a growth technology cheaper and easier to apply in industry. Although usually presented as a good candidate to make cheap panels, CIGS uses rare and expensive materials as In and Ga. The price evolution of these materials might jeopardize CIGS future. This thesis presents three different studies. The first is the study of different processes for the incorporation of Ga in a hybrid CIGS growth system. This system is based on sputtering and thermal evaporation. This technology is, in principle, easier to be applied in the industry and solar cells with efficiencies around to 7% were fully made in Aveiro. In the second part of this thesis, a new material to replace CIGS in thin film solar cells is studied. The growth conditions and fundamental properties of Cu2ZnSnSe4 (CZTSe) were studied in depth. Suitable conditions of temperature and pressure for the growth of this material are reported. Its band gap energy was estimated at 1.05 eV and the Raman scattering peaks were identified. Solar cells made with this material showed efficiencies lower than 0.1%. Finally, preliminary work regarding the incorporation of selenium in Cu2ZnSnS4 (CZTS) thin films was carried out. The structural and morphological properties of thin films of Cu2ZnSn(S,Se)4 have been studied and the results show that the incorporation of selenium is higher in films with precursors rather with already formed Cu2SnS3 or Cu2ZnSnS4 thin films. A solar cell with 0.9 % of efficiency was prepared.
As células solares de filmes finos têm nos últimos anos ganho cota de mercado aos tradicionais painéis fotovoltaicos de Silício. Estes desenvolvimentos devem-se em grande parte ao painéis baseados em CdTe cujo desenvolvimento começou mais cedo que os seus competidores. Os painéis baseados em Cu(In,Ga)Se2 (CIGS), apesar de serem mais eficientes tanto numa escala industrial como em laboratório, necessitam de uma tecnologia de crescimento que seja barata e de fácil aplicação na indústria. Apesar de se apresentarem como um bom candidato para painéis baratos o CIGS usa materiais caros e raros na crosta terrestre como o In e o Ga. A evolução do preço destes materiais podem comprometer o seu futuro. Nesta tese são apresentados três estudos diferentes. O primeiro é o estudo de diferentes processos de incorporação de Ga em CIGS crescido por um sistema híbrido de pulverização catódica e evaporação térmica. Esta tecnologia é, em princípio, mais fácil de ser aplicada a nível industrial e células solares feitas em Aveiro com eficiências próximas dos 7% foram produzidas. Numa segunda parte, outro material cujas propriedades o aponta como possível substituto ao CIGS é estudado. As condições de crescimento e propriedades fundamentais do Cu2ZnSnSe4 (CZTSe) foram estudados. São apresentadas condições de temperatura e de pressão para o crescimento reprodutível deste material. O seu hiato energético foi estimado em 1.05 eV e descobriu-se que podem existir flutuações de bandas de potencial que influenciam as suas propriedades ópticas. As células preparadas com CZTSe mostraram eficiências baixas, inferiores a 0.1% Finalmente uma abordagem inicial à incorporação de Selénio em filmes finos de Cu2ZnSnS4 é feita. As propriedades estruturais e morfológicas de filmes finos de Cu2ZnSn(S,Se)4 foram estudadas e os resultados mostram que a incorporação de Selénio é maior em filmes precursores do que directamente em filmes finos de Cu2SnS3 ou Cu2ZnSnS4. Uma célula solar com eficiência de conversão de 0.9 % foi preparada.
FCT; POPH; FSE
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Bittau, Francesco. "Analysis and optimisation of window layers for thin film CDTE solar cells." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/32642.
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The work presented in this thesis focuses on the investigation and improvement of the window stack of layers for thin film CdTe solar cells fabricated in the Center for Renewable Energy Systems Technology (CREST) laboratories. In particular the aim was to change the standard structure including TCO, high resistive transparent (HRT)layer and CdS which is limited by the low transparency of the CdS layer, to a better performing one. The first result chapter of the thesis describes the study of ZnO HRT layers. ZnO thin films were deposited by radio frequency (RF) magnetron sputtering with different structural, optical and electrical properties which were characterized by X-ray diffraction, electron microscopy, spectrophotometry, Hall Effect method and 4-point probe. ZnO films were then incorporated in CdTe solar cells with the structure: FTO/ZnO/CdS/CdTe/Au back contact and the performance of these devices were compared with the film properties to single out trends and identify optimal film characteristics. By varying the deposition pressure of ZnO films, it was possible to increase their transparency and significantly increase their resistivity. While better transparency positively affected the solar cell current density output and efficiency, the resistivity of ZnO films did not show any clear impact on device efficiency. By increasing the deposition temperature the ZnO film grain size was increased. Increased FF was observed in devices incorporating ZnO layers with bigger grains, although this gain was partially counterbalanced by the Voc degradation, leading to a limited efficiency improvement. Finally the addition of oxygen had the main effect of increasing the resistivity of ZnO films, similarly to what happened with the increase of the sputtering pressure. In this case however, an improvement of FF, Jsc and efficiency was observed, especially at an O2/Ar ratio of 1%. By simulating the solar cells behavior with SCAPS-1D, it was found that these performance change can be explained by the variation of interface properties, precisely the amount of interface defects, rather than by bulk properties. The study presented in the second result chapter focuses on magnesium-doped zinc oxide (MZO) and the variation of its energy band structure. MZO was initially used as the HRT layer within a solar cell structure: FTO/MZO/CdS/CdTe/Au back contact. Sputtering MZO films with a target containing MgO 11 weight% and ZnO 89 weight% allowed for and increased band gap from 3.3 eV of intrinsic ZnO to 3.65 eV for MZO deposited at room temperature. Increasing the superstrate deposition temperature allowed for a further band gap increase up to 3.95 eV at 400 °C due mainly to an conduction band minimum upward shift. It was highlighted the importance to create a positive conduction band offset with the MZO layer conduction band slightly above the CdS conduction band, with an optimum found in this case to be 0.3 eV (efficiency 10.6 %). By creating a positive conduction band offset all the performance parameters (Voc, FF, Jsc, efficiency) significantly increased. One of the reasons for this improvement was found to be a diminished interface recombination due to a more ideal MZO/CdS band alignment. In the second part of this investigation the MZO was used as a replacement for the CdS in a simplified structure: FTO/MZO/CdTe/Au back contact. The concepts used to optimise the performance of these devices also involved tuning the conduction band alignment between MZO/CdTe and efficiencies of 12.5 % were achieved with a at conduction band offset. The efficiency increase was achieved mainly thanks to a better transparency of the MZO layer and a higher Jsc output, compared to devices using a CdS buffer layer. The MZO buffers have been tested in combination with different TCOs. Results are presented in the third result chapter and showed that AZO is a good alternative to FTO working effectively in combination with MZO. AZO/MZO efficiency thin film CdTe solar cells (12.6%, compared to 12.5% with FTO). It was found that increasing the IR transparency of the TCOs leads to a potentially higher Jsc. Achieving a better transparency was obtained by using TCOs with high mobility and lower carrier concentration (AZO and ITiO) and also by using a boro-aluminosilicate glass with low iron content. ITiO yielded the best opto-electrical properties among all the TCO materials. Devices incorporating ITiO however, showed lower performance then those using FTO and AZO. ITO/MZO windows also yielded poor performance. In addition, the ITO films deposited had a high carrier concentration leading to a high NIR absorption by plasma resonance and resulted not ideal for application in thin film CdTe PV.
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Teran-Escobar, Gerardo, David M. Tanenbaum, Eszter Voroshazi, Martin Hermenau, Kion Norrman, Matthew T. Lloyd, Yulia Galagan, et al. "On the stability of a variety of organic photovoltaic devices by IPCE and in situ IPCE analyses – the ISOS-3 inter-laboratory collaboration." Royal Society of Chemistry, 2012. https://tud.qucosa.de/id/qucosa%3A27818.
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This work is part of the inter-laboratory collaboration to study the stability of seven distinct sets of state-of-the-art organic photovoltaic (OPV) devices prepared by leading research laboratories. All devices have been shipped to and degraded at RISØ-DTU up to 1830 hours in accordance with established ISOS-3 protocols under defined illumination conditions. In this work, we apply the Incident Photon-to-Electron Conversion Efficiency (IPCE) and the in situ IPCE techniques to determine the relation between solar cell performance and solar cell stability. Different ageing conditions were considered: accelerated full sun simulation, low level indoor fluorescent lighting and dark storage. The devices were also monitored under conditions of ambient and inert (N2) atmospheres, which allows for the identification of the solar cell materials more susceptible to degradation by ambient air (oxygen and moisture). The different OPVs configurations permitted the study of the intrinsic stability of the devices depending on: two different ITO-replacement alternatives, two different hole extraction layers (PEDOT:PSS and MoO3), and two different P3HT-based polymers. The response of un-encapsulated devices to ambient atmosphere offered insight into the importance of moisture in solar cell performance. Our results demonstrate that the IPCE and the in situ IPCE techniques are valuable analytical methods to understand device degradation and solar cell lifetime.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Gečys, Paulius. "Ultrashort pulsed laser processing of thin-films for solar cells." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20121001_093555-45841.
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Present PhD thesis is the experimental and theoretical analysis of thin layer ultrashort pulsed laser ablation processes for photovoltaic devices. Experimental work was supported by modeling and simulation of energy coupling and dissipation inside the layers. The absorbed laser energy was transformed to localized transient heating inside the structure. Selectiveness of the ablation process was defined by optical and mechanical properties of the materials, and selection of the laser wavelength facilitated control of the structuring process. The 1064 nm wavelength was found optimal for the CIGS solar cell scribing in terms of quality and process speed. It is very positive result for industrial applications as the cost and the system complexity are decreased. The solar cell efficiency test revealed minor degradation in photo-electrical efficiency after the laser scribing was applied to the solar cell samples. Lock-in thermography measurements did not revealed any internal shunt formation during laser scribing with picosecond pulse duration. Picosecond lasers with fundamental harmonics and high repetition rates can be used to accomplish efficient and fast scribing process which is able to fit the demands for industrial solar cell scribing applications.Disertacijos darbo tikslas buvo, modeliuojant bei vykdant eksperimentus, suprasti plonų sluoksnių, naudojamų Saulės elementuose, abliacijos procesus ultratrumpais impulsais, siekiant juos pritaikyti integruotų jungčių fotovoltiniuose moduliuose formavimui. Eksperimento rezultatams pagrysti buvo vykdomas lazerio spinduliuotės sklidimo bei pasiskirstymo plonasluoksnėje Saulės elemento struktūroje modeliavimas. Sugerta lazerio energija lokaliai užkaitiną medžiagą. Kadangi lazerinio proceso selektyvumas priklauso nuo medžiagos optinių savybių, todėl yra itin svarbu parinkti tinkamą lazerio spinduliuotės bangos ilgį, norint sukaupti spinduliuotę reikiamame plonasluoksnės struktūros sluoksnyje. Nustatyta, kad fundamentinė pikosekundinio lazerio spinduliuotė (1064 nm) yra optimaliausia P3 tipo rėžio formavimui CIGS Saulės elemente. Pramonės taikymams tai yra itin svarbu, nes tokiu atveju mažėja industrinės lazerinės sistemos sudėtingumas bei kaina. Saulės elementų efektyvumo tyrimai parodė nežymų fotoelektrinio efektyvumo sumažėjimą po lazerinio apdirbimo ultra trumpais impulsais, tačiau nebuvo užfiksuota defektų generacijos lazeriais paveiktose kanalo kraštų zonose. Disertacijoje pasiūlyti ir išbandyti pluošto formavimo ir lygiagretaus sluoksnių raižymo metodai, didinantys proceso našumą ir raižymo kokybę. Pikosekundiniai, didelio impulsų pasikartojimo dažnio lazeriai gali būti panaudoti didelės spartos bei aukštos kokybės Saulės elementų raižymo procesuose.
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Chen, Shuqun. "Thin films deposition for energy efficient windows and solar cells." Thesis, Queen Mary, University of London, 2016. http://qmro.qmul.ac.uk/xmlui/handle/123456789/18422.
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This work mainly investigates the use of aerosol assisted chemical vapour deposition (AACVD) process to fabricate thin film materials for energy efficient glazing and thin film solar cells applications. Ga-doped ZnO thin films were firstly deposited onto glass substrates by AACVD of zinc and gallium acetylacetonates in methanol. After optimizing the doping concentration, film thickness and heating temperature, ZnO:Ga coatings with high visible transparency (> 80 %) and infrared reflection (up to 48.9 % at 2500 nm) were obtained, which is close to the optical requirements for commercial energy saving glazing. Pyramid-shaped and plate-shaped zinc oxides films were then deposited on glass substrates by AACVD of zinc-acetate-dihydrate, acetic acid and deionized water in methanol. These surface-textured ZnO films exhibited good visible transparency (~70 %), low sheet resistance (~60 Ω sq-1) and ultra large haze factor (up to 98.5 %), which is the most hazy ZnO ever reported and can be potentially used as the front contact in thin-film solar cells. Finally, uniform compact CH3NH3PbI3 perovskite films with high phase purity and micron-sized pinhole-free grains were deposited on glass substrates by a novel two-step and three-step sequential AACVD process. In conclusion, AACVD shows a great potential for the scalable fabrication of ZnO-based and organometallic halide-based thin film materials.
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Alfadhili, Fadhil K. "Development of Back Contacts for CdTe Thin Films Solar Cells." University of Toledo / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1588962981116943.
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McCann, Michelle Jane, and michelle mccann@uni-konstanz de. "Aspects of Silicon Solar Cells: Thin-Film Cells and LPCVD Silicon Nitride." The Australian National University. Faculty of Engineering and Information Technology, 2002. http://thesis.anu.edu.au./public/adt-ANU20040903.100315.
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This thesis discusses the growth of thin-film silicon layers suitable for solar cells using
liquid phase epitaxy and the behaviour of oxide LPCVD silicon nitride stacks on silicon
in a high temperature ambient.¶
The work on thin film cells is focussed on the characteristics of layers grown using liquid
phase epitaxy. The morphology resulting from different seeding patterns, the transfer of
dislocations to the epitaxial layer and the lifetime of layers grown using oxide compared
with carbonised photoresist barrier layers are discussed. The second half of this work
discusses boron doping of epitaxial layers. Simultaneous layer growth and boron doping
is demonstrated, and shown to produce a 35um thick layer with a back surface field
approximately 3.5um thick.¶
If an oxide/nitride stack is formed in the early stages of cell processing, then characteristics of the nitride may enable increased processing flexibility and hence the realisation
of novel cell structures. An oxide/nitride stack on silicon also behaves as a good anti-
reflection coating. The effects of a nitride deposited using low pressure chemical vapour
deposition on the underlying wafer are discussed. With a thin oxide layer between the
silicon and the silicon nitride, deposition is shown not to significantly alter effective life-times.¶
Heating an oxide/nitride stack on silicon is shown to result in a large drop in effective
Lifetimes. As long as at least a thin oxide is present, it is shown that a high temperature
nitrogen anneal results in a reduction in surface passivation, but does not significantly
affect bulk lifetime. The reduction in surface passivation is shown to be due to a loss of
hydrogen from the silicon/silicon oxide interface and is characterised by an increase in
Joe. Higher temperatures, thinner oxides, thinner nitrides and longer anneal times are all
shown to result in high Joe values. A hydrogen loss model is introduced to explain the
observations.¶
Various methods of hydrogen re-introduction and hence Joe recovery are then discussed
with an emphasis on high temperature forming gas anneals. The time necessary
for successful Joe recovery is shown to be primarily dependent on the nitride thickness
and on the temperature of the nitrogen anneal. With a high temperature forming gas
anneal, Joe recovery after nitrogen anneals at both 900 and 1000oC and with an optimised
anti-reflection coating is demonstrated for chemically polished wafers.¶
Finally the effects of oxide/nitride stacks and high temperature anneals in both nitrogen
and forming gas are discussed for a variety of wafers. The optimal emitter sheet
resistance is shown to be independent of nitrogen anneal temperature. With textured
wafers, recovery of Joe values after a high temperature nitrogen anneal is demonstrated
for wafers with a thick oxide, but not for wafers with a thin oxide. This is shown to be
due to a lack of surface passivation at the silicon/oxide interface.
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Besharat, Zahra. "Adsorption of molecular thin films on metal and metal oxide surfaces." Doctoral thesis, KTH, Materialfysik, MF, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-195613.
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Metal and metal oxides are widely used in industry, and to optimize their performance their surfaces are commonly functionalized by the formation of thin films. Self-assembled monolayers (SAMs) are deposited on metals or metal oxides either from solution or by gas deposition. Thiols with polar terminal groups are utilized for creating the responsive surfaces which can interact electrostatically with other adsorbates. Surface charge effects wetting and adhesion, and many other surface properties. Polar terminal groups in thiols could be used to modify these factors. Mixed SAMs can provide more flexible surfaces, and could change the resulting surface properties under the influence of factors such as pH, temperature, and photo-illumination. Therefore, in order to control these phenomena by mixed polar-terminated thiols, it is necessary to understand the composition and conformation of the mixed SAMs and their response to these factors. In this work, mixtures of thiols with carboxylic and amino terminal groups were studied. Carboxylic and amino terminal groups of thiol interact with each other via hydrogen bonding in solution and form a complex. Complexes adsorb to the surface in non-conventional orientations. Unmixed SAMs from each type, either carboxylic terminated thiols or amino terminated thiols are in standing up orientation while SAMs from complexes are in an axially in-plane orientation. Selenol is an alternative to replace thiols for particular applications such as contact with biological matter which has a better compatibility with selenol than sulfur. However, the Se-C bond is weaker than the S-C bond which limits the application of selenol. Understanding the selenol adsorption mechanism on gold surfaces could shed some light on Se-C cleavage and so is investigated in this work. Se-C cleavage happens in the low coverage areas on the step since atoms at steps have lower coordination making them more reactive than atoms on the terraces. Another area where the self-assembly of molecules is of importance is for dye sensitized solar cells, which are based on the adsorption of the dye onto metal oxides surfaces such as TiO2.The interface between the SAM of dye and the substrate is an important factor to consider when designing dyes and surfaces in dye sensitized solar cells (DSSCs). The quality of the self-assembled monolayers of the dye on the TiO2 surface has a critical influence on the efficiency of the DSSCs. Creation of just a monolayer of dye on the surface could lead to an efficient current of photo-excited electrons to the TiO2 and degeneration of the dye by redox. This work, T-PAC dye showed island growth with some ad-layer that is not in contact with the surface, whereas the MP13 dye adsorption is laminar growth. Cuprite (Cu2O) is the initial and most common corrosion product for copper under atmospheric conditions. Copper could be a good replacement for noble metal as catalysts for methanol dehydrogenation. Knowledge about the structure of Cu2O(100) and Cu2O(111) surfaces could be used to obtain a deeper understanding of methanol dehydrogenation mechanisms with respect to adsorption sites on the surfaces. In this work, a detailed study was done of Cu2O(100) surface which revealed the possible surface structures as the result of different preparation conditions. Studies of the structure of Cu2O(100) and Cu2O(111) surfaces show that Cu2O(100) has a comparatively stable surface and reduces surface reactivity. As a consequence, dehydrogenation of methanol is more efficient on the Cu2O(111) surface. The hydrogen produced from methanol dehydrogenation is stored in oxygen adatom sites on both surfaces.QC 20161107
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Ahmed, Fatema. "Structural properties and optical modelling of SiC thin films." University of the Western Cape, 2020. http://hdl.handle.net/11394/7284.
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>Magister Scientiae - MScAmorphous silicon carbide (a-SiC) is a versatile material due to its interesting mechanical, chemical and optical properties that make it a candidate for application in solar cell technology. As a-SiC stoichiometry can be tuned over a large range, consequently is its bandgap. In this thesis, amorphous silicon carbide thin films for solar cells application have been deposited by means of the electron-beam physical vapour deposition (e-beam PVD) technique and have been isochronally annealed at varying temperatures. The structural and optical properties of the films have been investigated by Fourier transform Infrared and Raman spectroscopies, X-ray diffraction, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy and UV-VIS-NIR spectroscopy. The effect of annealing is a gradual crystallization of the amorphous network of as-deposited silicon carbide films and consequently the microstructural and optical properties are altered. We showed that the microstructural changes of the as-deposited films depend on the annealing temperature. High temperature enhances the growth of Si and SiC nanocrystals in amorphous SiC matrix. Improved stoichiometry of SiC comes with high band gap of the material up to 2.53 eV which makes the films transparent to the visible radiation and thus they can be applied as window layer in solar cells.
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Fang, Mei. "Properties of Multifunctional Oxide Thin Films Despostied by Ink-jet Printing." Doctoral thesis, KTH, Teknisk materialfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102021.
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Ink-jet printing offers an ideal answer to the emerging trends and demands of depositing at ambient temperatures picoliter droplets of oxide solutions into functional thin films and device components with a high degree of pixel precision. It is a direct single-step mask-free patterning technique that enables multi-layer and 3D patterning. This method is fast, simple, easily scalable, precise, inexpensive and cost effective compared to any of other methods available for the realization of the promise of flexible, and/or stretchable electronics of the future on virtually any type of substrate. Because low temperatures are used and no aggressive chemicals are required for ink preparation, ink-jet technique is compatible with a very broad range of functional materials like polymers, proteins and even live cells, which can be used to fabricate inorganic/organic/bio hybrids, bio-sensors and lab-on-chip architectures. After a discussion of the essentials of ink-jet technology, this thesis focuses particularly on the art of designing long term stable inks for fabricating thin films and devices especially oxide functional components for electronics, solar energy conversion, opto-electronics and spintronics. We have investigated three classes of inks: nanoparticle suspension based, surface modified nanoparticles based, and direct precursor solution based. Examples of the films produced using these inks and their functional properties are: 1) In order to obtain magnetite nanoparticles with high magnetic moment and narrow size distribution in suspensions for medical diagnostics, we have developed a rapid mixing technique and produced nanoparticles with moments close to theoretical values (APL 2011 and Nanotechnology 2012). The suspensions produced have been tailored to be stable over a long period of time. 2)In order to design photonic band gaps, suspensions of spherical SiO2 particles were produced by chemical hydrolysis (JAP 2010 and JNP 2011 - not discussed in the thesis). 3) Using suspension inks, (ZnO)1-x(TiO2)x composite films have been printed and used to fabricate dye sensitized solar cells (JMR 2012). The thickness and the composition of the films can be easily tailored in the inkjet printing process. Consequently, the solar cell performance is optimized. We find that adding Ag nanoparticles improves the ‘metal-bridge’ between the TiO2 grains while maintaining the desired porous structure in the films. The photoluminescence spectra show that adding Ag reduces the emission intensity by a factor of two. This indicates that Ag atoms act as traps to capture electrons and inhibit recombination of electron-hole pairs, which is desirable for photo-voltaic applications. 4) To obtain and study room temperature contamination free ferromagnetic spintronic materials, defect induced and Fe doped MgO and ZnO were synthesized ‘in-situ’ by precursor solution technique (preprints). It is found that the origin of magnetism in these materials (APL 2012 and MRS 2012) is intrinsic and probably due to charge transfer hole doping. 5) ITO thin films were fabricated via inkjet printing directly from liquid precursors. The films are highly transparent (transparency >90% both in the visible and IR range, which is rather unique as compared to any other film growth technique) and conductive (resistivity can be ~0.03 Ω•cm). The films have nano-porous structure, which is an added bonus from ink jetting that makes such films applicable for a broad range of applications. One example is in implantable biomedical components and lab-on-chip architectures where high transparency of the well conductive ITO electrodes makes them easily compatible with the use of quantum dots and fluorescent dyes. In summary, the inkjet patterning technique is incredibly versatile and applicable for a multitude of metal and oxide deposition and patterning. Especially in the case of using acetate solutions as inks (a method demonstrated for the first time by our group), the oxide films can be prepared ‘in-situ’ by direct patterning on the substrate without any prior synthesis stages, and the fabricated films are stoichiometric, uniform and smooth. This technique will most certainly continue to be a versatile tool in industrial manufacturing processes for material deposition in the future, as well as a unique fabrication tool for tailorable functional components and devices.QC 20120907
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Pounds, Tyler Deed. "An investigation of nanomaterials for solar cells, catalysts and sensors." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Spring2007/T_Pounds_042707.pdf.
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Yoo, Seunghyup. "Organic solar cells based on liquid crystalline and polycrystalline thin films." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1246%5F1%5Fm.pdf&type=application/pdf.
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Zoppi, Guillaume. "Studies of CdTe thin films and solar cells grown by MOCVD." Thesis, Durham University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418834.
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Kemell, Marianna. "Electrodeposition of CuInSe2 and doped ZnO thin films to solar cells." Helsinki : University of Helsinki, 2003. http://ethesis.helsinki.fi/julkaisut/mat/kemia/vk/kemell/.
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Dindault, Chloe. "Development of coevaporated hybrid perovskite thin films for solar cells applications." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX079/document.
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Les pérovskites hybrides célèbrent cette année leurs 10e anniversaire dans le domaine du photovoltaïque. En plus de la progression inégalée des rendements des cellules solaires, les pérovskites ont des propriétés optoélectroniques ajustables et peuvent être fabriquées par des procédés bas coûts, ce qui en fait de sérieuses candidates pour les cellules solaires multijunctions. Le réseau cristallin caractéristique des pérovskites hybrides offre une certaine liberté, supportant l’introduction partielle de cations et d’ions halogénures multiples. L’ajustement de la composition d’un matériau pérovskite se traduit par un ajustement de ces propriétés électroniques dont notamment sa structure de bandes. En adaptant la composition il est possible d’obtenir un matériau pérovskite avec une bande interdite de 1,7 eV qui serait parfaitement adapté pour une cellule tandem à base de Silicium cristallin. Les films minces de pérovskites peuvent être fabriqués par une grande diversité de techniques de dépôt, à partir de précurseurs ‘bon marché’ (CH3NH3I et PbI2 par exemple), par des procédés à basse température. Même si la grande majorité des films de pérovskites sont obtenus par la méthode d’enduction centrifuge, celle-ci ne permet pas l’obtention de films homogènes, sur grandes surfaces et de façon répétable. Etant donné l’enjeu industriel qui attend les pérovskites et l’intérêt croissant pour les structures tandems Silicium/Pérovskite, les méthodes sans solvant semblent plus adaptées. Déjà très largement utilisé dans l’industrie des OLEDs, le procédé de coévaporation thermique semble constituer une solution commercialement viable. Publiée pour la première fois en 2013, la synthèse par coévaporation des pérovskites est pour le moment encore étudiée par peu de groupes, car nécessitant des équipements plus coûteux. La présente thèse vise à mettre en place et développer la technique de coévaporation pour la fabrication de films de pérovskites hybrides pour des applications en cellules solaires.Afin d’évaluer la faisabilité du procédé, nous avons commencé notre travail sur un réacteur de démonstration, ce qui nous a permis d’appréhender la réponse à la sublimation des deux précurseurs. Nous avons très vite identifié le comportement du sel organique CH3NH3I comme étant problématique car difficilement contrôlable (s’évaporant sous forme de « nuage »), comme nous l’avions lu dans la littérature. En six mois d’utilisation de ce réacteur, nous avons fabriqué des films de pérovskites ayant permis d’atteindre des rendements de 9% sur des cellules solaires, malheureusement avec une faible reproductibilité (que nous expliquons en partie par le caractère aléatoire de l’évaporation du composé organique CH3NH3I). Nous nous sommes trouvés dans l’incapacité de comprendre plus en profondeur le procédé à cause d’un manque de fonctionnalités de l’équipement. Grâce à ces différents retours d’expérience nous avons pu concevoir, en étroite collaboration avec l’équipementier, un réacteur semi-industriel dédié à la fabrication de films de perovskites par coévaporation. Suite à sa mise en place, nous nous somme focalisé sur la problématique de la reproductibilité dans nos expériences en essayant de diminuer l’impact du nuage organique. Bien que les efficacités atteintes en cellules solaires pour des films coévaporés fussent moindres que pour des films déposés par la technique classique d’enduction centrifuge, nous soupçonnions néanmoins une meilleure homogénéité des films obtenus par voie sèche. Nous avons ainsi intégré à cette thèse une étude comparative voie liquide/voie sèche par le biais d’une technique de spectromicroscopie rayons X en SynchrotronHybrid perovskites celebrate this year their 10-year anniversary in the photovoltaic field. Besides the unprecedented rise in solar cells efficiencies, perovskite materials have tunable optical properties and can be manufactured at low cost, making them very promising candidates for the high efficiency, multijunction solar cells strategy. Perovskite crystal structure offers a relative degree of freedom, allowing the partial integration of multiple cations and halide ions. This chemical composition tuning translates into a bandgap tuning. Through fine chemical engineering, the 1.7 eV requirement for a c-Si-based tandem device can be achieved. Perovskite thin films can be prepared by a large variety of deposition techniques, from low cost precursors (CH3NH3I and PbI2 for instance), through low-temperature processes. While most of the reported works on perovskite thin films are based on the basic wet-process spincoating technique, this latter hardly allows large scale, homogeneous and reproducible deposition. With the future challenge of industrialization and the increasing interest for the Silicon/Perovskite tandem approach, solvent-free methods appear more suitable. Already widely implemented in the OLED industry, coevaporation stands as a viable option for perovskites’ future. Reported for the first time in 2013, coevaporated perovskites are still scarcely studied compared to wet-based techniques, requiring more expensive set ups. In the present thesis, we implemented and developed the coevaporation process to fabricate perovskite thin films for solar cells applications.Starting off on a proof-of-concept reactor to assess the feasibility of the technique, we got accustomed to the perovskite precursors behaviour and identify very early on the organic precursor to be hardly manageable, as reported in the literature. In six months, we were nonetheless able to obtain nice perovskite films leading to 9% efficient photovoltaic devices, unfortunately with a poor reproducibility that we think to be partially due to the cloud vapour behaviour of CH3NH3I. We eventually found ourselves missing some features on the equipment, preventing us from accurately get a grasp on the process. From this feedback we then designed, hand in hand with the manufacturer, a dedicated semi-industrial equipment for perovskite coevaporation. Following its implementation, we then focused on establishing the reproducibility of the method, trying to mitigate the parasitic effect of the organic compound. Even though the efficiencies in solar cells were still slightly lower for coevaporated perovskites, with respect to classical spincoated ones, we expected the material homogeneity to be in favour of the vacuum-based process. We then eventually integrated to this thesis a comparative study between wet- and dry-processed perovskite films using a Synchrotron-based X-ray spectromicroscopy technique
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JÃnior, Paulo Herbert FranÃa Maia. "Obtaining a thin film of FTO by spray-pyrolysis technique and sol-gel method for use in organic solar cells." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14347.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoThe growing interest in the use of new materials and their applications for photovoltaic systems has been a constant concern of the scientific community in recent years. This work is primarily engaged in the collection, characterization and photoactivity testing photovoltaic solar cells made of thin SnO2 doped fluoride films, the films were deposited by the technique of "spray-pyrolysis" and the Sol-Gel method in substrate glass. In glasses microscopy work with dimensions of 2.5 x 7.5 x 1 mm are used as matrices for the conductive substrates or transparent conductive oxides (TCO). These glasses have electrical resistance and transmittance adequate for the manufacture of photoelectrochemical solar cells activated by dyes. Besides making the glasses must be made conductive depositing a layer of titanium oxide, preparation of electrolyte, dye, assembly and characterization of the cells. The conductive substrate has a film of tin dioxide doped with fluorine (SnO2: F), the deposition is made with the aid of a compressor and a spray gun on the glass at a temperature of 600Â C from a solution made by the method Sol- gel (MSG). As characterization techniques were used: x-ray diffraction (EDX), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), UV-Vis and Van der Pauw method. The conductive glass has transmittance of 80% (400 nm - 800 nm). The cell with mesoporphyrin dye has Vac = 0.34V and Icc ~ 150μA. The experimental results obtained from these cells may contribute to the development of prototypes that can be used commercially in the capture of solar energy and its consequent transformation into electricity.
O crescente interesse no uso de novos materiais e suas aplicaÃÃes, para sistemas fotovoltaicos tem sido uma constante preocupaÃÃo da comunidade cientifica nos Ãltimos anos. O presente trabalho tem por objetivo principal a obtenÃÃo, caracterizaÃÃo e testes de fotoatividade de cÃlulas solares fotovoltaicas constituÃdas de filmes finos de SnO2 dopados com flÃor, os filmes foram depositados pela tÃcnica de âspray-pirÃliseâ e pelo mÃtodo Sol-Gel em substrato de vidro. Neste trabalho vidros de microscopia com dimensÃo de 2,5 x 7,5 cm x 1 mm, sÃo usados como matrizes para os substratos condutores ou Ãxidos condutores transparentes (OCTâs). Estes vidros possuem resistÃncia elÃtrica e transmitÃncia adequadas para confecÃÃo de cÃlulas solares fotoeletroquÃmicas ativadas por corantes. AlÃm de tornar os vidros condutores deve ser feita a deposiÃÃo de uma camada de Ãxido de titÃnio, preparaÃÃo de eletrÃlito, corante, montagem e caracterizaÃÃo das cÃlulas. O substrato condutor possui um filme de diÃxido de estanho dopado com flÃor (SnO2:F), a deposiÃÃo à feita com o auxilio de um compressor e uma pistola aerogrÃfica sobre o vidro à temperatura de 600ÂC a partir de uma soluÃÃo feita pelo mÃtodo Sol-Gel (MSG). Como tÃcnicas de caracterizaÃÃo foram usadas: difraÃÃo de raios-x (EDX), microscopia eletrÃnica de varredura (MEV), espectroscopia de energia dispersiva (EDS), Uv-Vis e mÃtodo de Van der Pauw. O vidro condutor apresenta transmitÃncia 80% (400 nm â 800 nm ). A cÃlula com corante mesoporfirina apresenta Vca = 0,34 V e Icc ~ 150μA. Os resultados experimentais obtidos dessas cÃlulas poderÃo contribuir para o desenvolvimento de protÃtipos que possam ser utilizados comercialmente na captaÃÃo de energia solar e sua conseqÃente transformaÃÃo em energia elÃtrica.
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Straub, Axel Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Polycrystalline silicon thin-film solar cells on glass by ion-assisted deposition." Awarded by:University of New South Wales. School of Electrical Engineering and Telecommunications, 2005. http://handle.unsw.edu.au/1959.4/22435.
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Polycrystalline silicon (pc-Si, grain size > 1??m, no amorphous tissue) on glass is an interesting material for thin-film solar cells due to the low costs, the abundance and the non-toxic character of Si, and the properties of pc-Si like long-term stability and lateral conductance. Glass as supporting material significantly complicates the fabrication process as it limits the thermal budget and the maximum temperature. In this work, the feasibility of forming large-grained pc-Si thin-film solar cells on glass by ion-assisted deposition (IAD) on aluminium-induced crystallisation (AIC) seed layers (ALICIA solar cells) is investigated. IAD allows epitaxial growth at high rate, and being based on evaporation, is of low cost (high source material usage, no toxic gases involved). High-quality epitaxy on (100)-oriented Si wafer substrates is demonstrated in a non{UHV environment, to further increase its industrial appli- cability. High{rate growth and a sacrificial protective layer control contamination problems associated with the non-UHV environment. The process is then trans- ferred to AIC-seeded glass and optimised, with particular focus on the influence of the glass. Using high-temperature rapid thermal annealing and hydrogenation as post-deposition treatments, ALICIA solar cells with a 1-Sun open-circuit voltage of 420 mV are achieved. Moreover, two novel characterisation techniques are presented. One allows the fast and non-destructive assessment of the structural quality of pc-Si films using opti- cal measurements. Furthermore, `impedance analysis', a novel capacitance-voltage measurement technique based on impedance spectroscopy, is presented. It allows the reliable determination of the absorber layer doping density and the built{in potential of non-ideal p-n junction solar cells. The latter is used to investigate the influence of post{deposition treatments on the n-type absorber layer doping of ALICIA solar cells. It is found, using temperature dependent impedance analysis, that unintentional doping and defects have a strong influence on the absorber layer doping. A maximum in the short-circuit current density of ALICIA solar cells is found for phosphorus concentrations in the absorber of 1??1017 cm??3. For such ALI- CIA cells a base difusion length in the range 600 - 950nm, a short{circuit current density in the range 10 - 13.5 mA/cm2 and an energy conversion efficiency of 2.2% are obtained.
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Mailoa, Jonathan P. "Anti-reflection zinc oxide nanocones for higher efficiency thin-film silicon solar cells." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/77250.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 77-80).
Thin film silicon solar cells, which are commonly made from microcrystalline silicon ([mu]c-Si) or amorphous silicon (a-Si), have been considered inexpensive alternatives to thick polycrystalline silicon (polysilicon) solar cells. However, the low solar efficiency of these thin film cells has become a major problem, which prevents thin film silicon cells from being able to compete with other solar cells in the market. One source of inefficiency is the light reflection off the interface between the thin film cell's top Transparent Conducting Oxide (TCO) and the light absorbing silicon. In this work, we demonstrate the use of nanocone textured ZnO as the anti-reflection surface that mitigates this problem. The tapered structure of the nanocone forms a smooth transition of refractive index on the interface between the TCO (ZnO) and the silicon, effectively acting as a wideband Anti-Reflection coating (AR coating). Finite Difference Time Domain simulation is used to estimate the optimal ZnO nanocone parameter (periodicity and height) to be applied on a single junction microcrystalline silicon ([mu]c-Si) solar cell. Relative improvement over 25% in optical performance is achieved in the simulated structure when compared to state-of-the-art [mu]c-Si cell structure. Cheap and scalable colloidal lithography method is then developed to fabricate ZnO nanocone with the desired geometry. Since the ZnO texturing technique works by depositing ZnO on nanocone-textured glass substrate, the technique is potentially applicable to Transparent Conducting Oxides other than ZnO as well, making it a useful TCO texturing technique for solar cell applications.
by Jonathan P. Mailoa.
M.Eng.
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Boman, Daniel. "Compositional gradients in sputtered thin CIGS photovoltaic films." Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-355462.
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Cu(In,Ga)Se2 (CIGS) is a semiconductor material and the basis of the promising thin-film photovoltaic technology with the same name. The CIGS film has a typical thickness of 1-2 mm, and solar cells based on CIGS technology has recently reached efficiencies of 23.3%. Ultra-thin CIGS solar cells use sub-micrometer thick films that require significantly less material and can be manufactured in a shorter amount oftime than films with typical thicknesses. With decreasing thickness, both electrical and optical losses get more significant and lower the overall performance. Electrical losses can be decreased by increasing the overall film quality and by utilising a graded bandgap throughout the CIGS layer. The band gap can be changed by varying the[Ga]/([Ga]+[In]) (GGI) ratio. Higher overall film quality and a higher band-gap towards the back of the absorber are expected to increase the performance. In this work, sputtered CIGS solar cells were made with different CIGS layer thicknesses, that ranged between 550-950 nm. Increased heat during deposition was examined and shown to increase the film quality and performance for all thicknesses. Two different ways of doping CIGS with Na was examined and it was found that higher Na content lead to an increasing predominance of the (112) plane. The bandgap was graded by varying the GGI composition throughout the CIGS layer and depth profiles were made with Glow-Discharge Optical Emission Spectroscopy (GDOES). It was found that a sputtered CuGaSe2 (CGS)layer below the CIGS-layer lead to a steep increase of the GGI near the back contact. When CGS made up 10% of the total CIGS layer thickness, a significant increase in performance was observed for all thicknesses. CIGS-absorbers with a less graded region with low GGI, making up 30% or 60% of the total CIGS layer thickness were made. A decrease in GGI in that region, was shown to increase the current but lower the voltage. No substantial increase in total performance compared to a fully graded CIGS layer was seen regardless of layer thickness. For further work the optical losses needs to be addressed and work on increasing the optical path in the CIGS layer needs to be done.
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Bottois, Clément. "Nanoparticules pour la réalisation de couches de transport de trous appliquées au photovoltaïque organique." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI025/document.
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Dans les cellules photovoltaïques organiques, le matériau utilisé pour le transport de trous entre la couche active et l'électrode, est généralement un polymère dopé, dont la stabilité peut être problématique. L'objectif de cette thèse a été de développer des matériaux inorganiques, a priori plus stables, pour remplacer les couches de polymères de transport de trous, tout en restant compatible avec les méthodes de dépôts par voie liquide. L'utilisation de nanoparticules dispersées en solution a été choisie car cela permet le dépôt à basse température, sans nécessité de conversion vers une couche fonctionnelle, contrairement aux voies sol-gel. Le premier objectif de ce travail a donc été l'obtention de nanoparticules d'oxyde de tungstène, hydraté ou non, et de thiocyanate de cuivre. Une synthèse de chauffage assisté par micro-ondes a été utilisée pour l'oxyde de tungstène, permettant d'obtenir des nanoparticules de 30 nm et monodisperses. Pour le thiocyanate de cuivre, il a été choisi de travailler par broyage. Les paramètres du broyage ont été optimisés pour obtenir des particules avec la plus faible distribution en taille possible. Le dépôt de ces dispersions de nanoparticules a permis l'obtention de couches minces et la caractérisation de leurs propriétés optoélectroniques, et notamment du travail de sortie, qui s'est révélé adapté pour une utilisation en dispositif. Des cellules solaires organiques de structures standard et inverse incorporant ces matériaux ont ensuite été réalisées. De bonnes performances ont été obtenues avec une couche active à base de P3HT, notamment en structure inverse où la possibilité d'utiliser le thiocyanate de cuivre a été démontrée pour la première fois. Le suivi des performances sous éclairement et atmosphère contrôlée a également été effectué et a montré un vieillissement rapide pour ces cellules comparées aux cellules de référence à couche de transport de trous polymèreIn organic solar cells, a doped polymer is the most used material for hole transport between the active layer and the electrode, but his stability can be an important issue. The goal of this PhD thesis was to develop inorganic materials, expected to be more stable, in order to replace polymer based hole transporting layers. Another requirement was to keep the compatibility with solution-based deposition methods. The target was to develop nanoparticle dispersions, deposited at low temperature and giving directly a functional layer, without the need of further treatments which are usually required via sol-gel processes. A first objective of the present work was thus the elaboration of nanoparticles of tungsten oxide, hydrated or non-hydrated, and copper thiocyanate. A microwave-assisted heating synthesis has been used for tungsten oxide, leading to mono-dispersed particles around 30 nm. Concerning copper thiocyanate, a ball milling technique has been chosen. The process parameters have been optimized to obtain nanoparticles to narrow the size distribution as much as possible. The deposition of the nanoparticles has allowed the formation of thin layers and the characterization of their optoelectronic properties, such as work function, which was shown to be a relevant parameter for a use in devices. Organic solar cells with standard or inverted structures have been fabricated using these materials as a hole transporting layer. Good photovoltaic performances have been obtained, especially in the inverted structure, in which the possibility to use copper thiocyanate has been demonstrated for the first time. Ageing experiments under light in a controlled atmosphere have also been carried out and have shown a rapid drop in performances for these cells compared to cells incorporating polymer based hole transport layers
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McCracken, R. O. "The copper-bismuth-sulphur material system and thin film deposition of Cu3BiS3 by sputtering and evaporation for the application of photovoltaic cells." Thesis, University of Leeds, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/9927.
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The semiconducting sulphosalt Wittichenite has been identified as a possible absorber material for thin film photovoltaic devices. It has the chemical formula Cu3BiS3 and its component elements are those of low toxicity and high abundance making it a very attractive prospect for photovoltaic devices.
The copper bismuth sulphur material system is not very well understood and information on it limited to a few small regions. To aid understanding of this system a pseudo-binary phase diagram along the CuS-Bi join of the Cu-Bi-S ternary phase diagram was constructed by making bulk samples of various compositions along the join and analysing them using X-ray diffraction and differential scanning calorimetry. This join was chosen because is crosses the point at which Cu3BiS3 would be expected to occur due to its stoichiometry. The CuS-Bi phase diagram shows Cu3BiS3 forms across a wide compositional range but is mixed with either bismuth metal or copper sulphides depending on composition.
Films of Cu3BiS3 were made using sputtered copper and bismuth films annealed in a sulphur atmosphere and thermal co- evaporation of copper sulphide and bismuth.
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Klasen, Alexander [Verfasser]. "Synthesis and Analysis of Thin Films for Perovskite Solar Cells / Alexander Klasen." Mainz : Universitätsbibliothek der Johannes Gutenberg-Universität Mainz, 2020. http://d-nb.info/1224895940/34.
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Schabauer, Johann Josef Anton. "Dye sensitised solar cells and time resolved photoacoustic calorimetry on thin films." Thesis, Swansea University, 2008. https://cronfa.swan.ac.uk/Record/cronfa42365.
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This work is primarily a study of the photoelectrochemical characterisation of dye sensitised solar cells. The specific parts of the cell and their role towards overall cell efficiency are considered in detail. A large number of cells have been characterised in which the nature of: the TiO2 semiconductor, the absorbing dye, electrolyte, and the nature of the conducting electrodes, were varied. The photoelectric properties of the cells were measured using a Xe-arc sun simulator mimicking the incident solar radiation at ground level. Cell voltage and current were measured while operating under different temperatures and irradiation intensities. It was found, that a thick layer of Pt at the counter electrode did not improve the performance of the cell. Plastic cells are smaller and lighter, but lack in efficiency when compared to glass cells which is down to the lower series resistance of the transparent conducting oxide used. Higher concentrated electrolytes can lead to better results. At higher illumination intensities, back irradiation of the cell becomes favourable down to charge transfer limitations, especially in gel and solid electrolytes. Another significant part of the research documented in this thesis was the development of thin film and interfacial time resolved photoacoustic calorimetry as a novel method for the time resolved measurement of non-radiative processes of dyes adsorbed at interfaces or as thin solid films. In our case, the dyes were either adsorbed on the mesoporous TiO2 semiconductor film used in dye sensitised solar cells, or incorporated in a polymer matrix. Using this approach, we were able to directly measure triplet state lifetimes and quantum yields of charge injection into the semiconductor. Possible further applications for this method are discussed.