Dissertations / Theses: 'Mesoscopic perovskite solar cells'

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Yang, Lei. "Hole Transport Materials for Solid-State Mesoscopic Solar Cells." Doctoral thesis, Uppsala universitet, Fysikalisk kemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-232271.

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The solid-state mesoscopic solar cells (sMSCs) have been developed as a promising alternative technology to the conventional photovoltaics. However, the device performance suffers from the low hole-mobilities and the incomplete pore filling of the hole transport materials (HTMs) into the mesoporous electrodes. A variety of HTMs and different preparation methods have been studied to overcome these limitations. There are two types of sMSCs included in this doctoral thesis, namely solid-state dye-sensitized solar cells (sDSCs) and organometallic halide perovskite based solar cells. Two different types of HTMs, namely the small molecule organic HTM spiro-OMeTAD and the conjugated polymer HTM P3HT, were compared in sDSCs. The photo-induced absorption spectroscopy (PIA) spectra and spectroelectrochemical data suggested that the dye-dye hole conduction occurs in the absence of HTM and appears to be of significant importance to the contribution of hole transport. The PIA measurements and transient absorption spectroscopy (TAS) indicated that the oxidized dye was efficiently regenerated by a small molecule organic HTM TPAA due to its excellent pore filling. The conducting polymer P3HT was employed as a co-HTM to transfer the holes away from TPAA to prohibit the charge carrier recombination and to improve the hole transport. An alternative small molecule organic HTM, MeO-TPD, was found to outperform spiro-OMeTAD in sDSCs due to its more efficient pore filling and higher hole-mobility. Moreover, an initial light soaking treatment was observed to significantly improve the device performance due to a mechanism of Li+ ion migration towards the TiO2 surface. In order to overcome the infiltration difficulty of conducting polymer HTMs, a state-of-the-art method to perform in-situ photoelectrochemical polymerization (PEP) in an aqueous micellar solution of bis-EDOT monomer was developed as an environmental-friendly alternative pathway with scale-up potential for constructing efficient sDSCs with polymer HTMs. Three different types of HTMs, namely DEH, spiro-OMeTAD and P3HT, were used to investigate the influence of HTMs on the charge recombination in CH3NH3PbI3 perovskite based sMSCs. The photovoltage decay measurements indicate that the electron lifetime (τn) of these devices decreases by one order of magnitude in the sequence τspiro-OMeTAD > τP3HT > τDEH.

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Lindblad, Rebecka. "Electronic Structures and Energy Level Alignment in Mesoscopic Solar Cells : A Hard and Soft X-ray Photoelectron Spectroscopy Study." Doctoral thesis, Uppsala universitet, Molekyl- och kondenserade materiens fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-221450.

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Photoelectron spectroscopy is an experimental method to study the electronic structure in matter. In this thesis, a combination of soft and hard X-ray based photoelectron spectroscopy has been used to obtain atomic level understanding of electronic structures and energy level alignments in mesoscopic solar cells. The thesis describes how the method can be varied between being surface and bulk sensitive and how to follow the structure linked to particular elements. The results were discussed with respect to the material function in mesoscopic solar cell configurations. The heart of a solar cell is the charge separation of photoexcited electrons and holes, and in a mesoscopic solar cell, this occurs at interfaces between different materials. Understanding the energy level alignment between the materials is important for developing the function of the device. In this work, it is shown that photoelectron spectroscopy can be used to experimentally follow the energy level alignment at interfaces such as TiO2/metal sulfide/polymer, as well as TiO2/perovskite. The electronic structures of two perovskite materials, CH3NH3PbI3 and CH3NH3PbBr3 were characterized by photoelectron spectroscopy and the results were discussed with support from quantum chemical calculations. The outermost levels consisted mainly of lead and halide orbitals and due to a relatively higher cross section for heavier elements, hard X-ray excitation was shown useful to study the position as well as the orbital character of the valence band edge. Modifications of the energy level positions can be followed by core level shifts. Such studies showed that a commonly used additive in mesoscopic solar cells, Li-TFSI, affected molecular hole conductors in the same way as a p-dopant. A more controlled doping can also be achieved by redox active dopants such as Co(+III) complexes and can be studied quantitatively with photoelectron spectroscopy methods. Hard X-rays allow studies of hidden interfaces, which were used to follow the oxidation of Ti in stacks of thin films for conducting glass. By the use of soft X-rays, the interface structure and bonding of dye molecules to mesoporous TiO2 or ZnO could be studied in detail. A combination of the two methods can be used to obtain a depth profiling of the sample.

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Stenberg, Jonas. "Perovskite solar cells." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-137302.

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Perovskite solar cells (PSC) performance has risen rapidly the last few years with the current record having power conversion efficiency (PCE) of 22.1 %. This has attracted a lot of attention towards this alternative solar cell that can be manufactured with less energy and toxic material than traditional silicon solar cells. The purpose of this thesis is to reproduce high performance PSC from known recipe by Zhang et al. with potential of PCE reaching above 18 %. The thesis covers the theory regarding how a PSC operates, how they are measured and which parameters are important for a high performance PSC. The thesis includes a detailed manuscript on how to manufacture high performance PSC layer by layer and how to characterize the performance of the cells by IV-measurements. Furthermore, it includes scanning electron microscopy (SEM), by which the cells surface layers and cross-section could be evaluated. The result shows that it is possible to reproduce the PSC from literature and achieve a PCE of 18.8 %. However, the cells PCE decrease by 15 % during 2 hours of constant illumination, due to lack of stability. The manufactured PSC was used to power two catalysts that splits water into O2 and H2 and managed to reach a solar to hydrogen conversion efficiency (STHCE) of 13 %.

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Bett, Alexander Jürgen [Verfasser], and Stefan [Akademischer Betreuer] Glunz. "Perovskite silicon tandem solar cells : : two-terminal perovskite silicon tandem solar cells using optimized n-i-p perovskite solar cells." Freiburg : Universität, 2020. http://d-nb.info/1214179703/34.

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Pockett, Adam. "Characterization of perovskite solar cells." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715261.

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A range of electrical characterization techniques previously used for DSSC have been transferred to the study of planar perovskite devices. These include impedance spectroscopy (EIS), intensity modulated photovoltage spectroscopy (IMVS) and open-circuit voltage decay measurements (OCVD). An investigation into the observed response from these measurements has been carried out in order to gain a deeper understanding of device operation. Multiple processes with time constants on the microsecond, millisecond and second timescale were observed. The complimentary frequency and time domain techniques have been employed, showing excellent agreement between the two types of measurement. The high frequency (microsecond) process was found to be purely electronic in nature, which was linked to recombination. The geometric capacitance was shown to dominate this response, with accumulation of charge in the planar perovskite layer not observed. The lower frequency (millisecond and second timescale) processes were found to be linked to the coupling between recombination and the movement of ions. The low frequency EIS and IMVS measurements revealed that the recombination resistance was frequency dependent. The rate of change of the recombination resistance was found to be linked to the diffusion of ionic species. Activation energies for these processes were obtained (EA=0.55-0.66 eV) and shown to be in good agreement to computationally calculated values from literature for iodide vacancy migration. The same slow processes were also studied in the time domain using open-circuit photovoltage rise and decay measurements from well-defined equilibrium conditions. Comparable activation energies were also found using these techniques. The vacancy defect concentration was calculated to be 3x1019 cm-3, which is high enough for ionic double layers at the contacts to completely screen the built-in voltage across the perovskite at equilibrium in the dark. The slow dynamic processes observed under illumination or applied bias are therefore due to the rearrangement of ions in response to a changing electric field. As this rearrangement occurs, the rate of recombination is altered.

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Wei, Rongsheng. "Modelling of perovskite solar cells." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/119218/1/Rongsheng_Wei_Thesis.pdf.

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This project focuses on simulation performance of perovskite solar cells using two models. One is a simplified model developed for perovskite absorber layer of PSCs by using matlab program to investigate the effect of density of state, relative dielectric permittivity and band gap energy of the perovskite material on the device performance. The other model is based on SCAPS to investigate the influence of hole mobility and band gap offset of different hole transport materials on device performance.

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Brivio, Federico. "Atomistic modelling of perovskite solar cells." Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.698992.

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This thesis focuses on the study of hybrid perovskites properties for the purposes of photovoltaic applications. During the almost four years PhD project that has lead to this thesis the record photovoltaic efficiency for this technology has in- creased from 10.9% to 22.1%. Such a significant pace of development can be com- pared with few other materials. It is for this reason that hybrid perovsites have at- tracted impressive research efforts. We approached the study of such unique ma- terials using computational ab-initio techniques, and in particular Density Func- tional Theory. We considered different materials, but most of the attention was concentrated on MAPI (CH 3 NH 3 PbI 3 ). The results are divided in three chapters, each exploring a different material prop- erty. The first chapter reports the electronic structure of the material bulk, sur- faces, and other electronic-related properties such as the rotation barrier for the organic component and the Berry phase polarization. The second chapter focuses on the vibrational properties primary employing the harmonic approximation but also extends to the quasi-harmonic approximation. The outcome of these calculations permitted us to calculate theoretical IR and Ra- man spectra which are in good agreement with different experimental measure- ments. The quasi-harmonic approximation was used to calculate temperature dependent properties, such as the Grüneisen parameter, the thermal dependence of heat capacity and the thermal volumetric expansion. The third and last chapter reviews the thermodynamic properties of binary halide compounds. The cobination of ab-initio calculations with the generalised quasi- chemical approximation has allowed to study the stability of mixed composition perovskites. The results certified a set of stable structures that could stand at the base of observed phenomena of photo-degradation of hybrid perovskite based devices. All three chapters have been written to understand the chemical and physical behaviour of hybrid perovskites and to extended and contribute to the under- standing of experimental work.

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Tan, Kwan Wee. "Commercialization potential of dye-sensitized mesoscopic solar cells." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/54206.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008. 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. 67-73). The price of oil has continued to rise, from a high of US$100 per barrel at the beginning 2008 to a new record of above US$140 in the recent weeks (of July). Coupled with increasing insidious greenhouse gas emissions, the need to harness abundant and renewable energy sources is never more urgent than now. The sun is the champion of all energy sources and photovoltaic cell production is currently the world's fastest growing energy market. Dye-sensitized solar cells (DSCs) are photoelectrochemical cells which mimic the natural photosynthesis process to generate solar electricity. Typically, a monolayer of dye sensitizer molecules is anchored onto a semiconductor mesoporous film such as TiO₂ to generate charges on exposure to illumination. The nanocrystalline particulate threedimensional network provides high surface area coverage for the photogeneration process and percolation of charges. In the thesis, we will review the current research efforts to optimize the DSC performance and develop probable applications to complement existing solid-state photovoltaic technologies. We believe the large and rapidly expanding solar market offers a prime commercial opportunity to deliver a DSC product for mass adoption by consumers. DSC is kept at a low production cost because it bypasses conventional vacuum-based semiconductor processing technologies, instead relying on solution and chemical processing routes. However, our cost modeling analysis show the TCO glass substrate and ruthenium dyes could constitute more than 90% of the overall materials cost. (cont.) Thus, we recommend new technological approaches must be taken to keep the substrate pricing low and continuously improve the energy conversion efficiencies to further lower the production cost. by Kwan Wee Tan. M.Eng.

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Noel, Nakita K. "Advances in hybrid solar cells : from dye-sensitised to perovskite solar cells." Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:e0f54943-546a-49cd-8fd9-5ff07ec7bf0a.

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This thesis presents a study of hybrid solar cells, specifically looking at various methods which can be employed in order to increase the power conversion efficiency of these devices. The experiments and results contained herein also present a very accurate picture of how rapidly the field of hybrid solar cells has progressed within the past three years. Chapters 1 and 2 present the background and motivation for the investigations undertaken, as well as the relevant theory underpinning solar cell operation. Chapter 2 also gives a brief review of the literature pertinent to the main types of devices investigated in this thesis; dye-sensitised solar cells, semiconductor sensitized solar cells and perovskite solar cells. Descriptions of the synthetic procedures, as well as the details of device fabrication and any measurement techniques used are outlined in Chapter 3. The first set of experimental results is presented in Chapter 4. This chapter outlines the synthesis of mesoporous single crystals (MSCs) of anatase TiO2 as well as an investigation of its electronic properties. Having shown that this material has superior electronic properties to the conventionally used nanoparticle films, they were then integrated into low temperature processed dye-sensitised solar cells and achieved power conversion efficiencies of &GT; 3&percnt;, exhibiting electron transport rates which were orders of magnitude higher than those obtained for the high temperature processed control films. Chapter 5 further investigates the use of MSCs in photovoltaic devices, this time utilising a more strongly absorbing inorganic sensitiser, Sb2S3. Utilising the readily tunable pore size of MSCs, these Sb2S3 devices showed an increase in voltage and fill factor which can be attributed to a decrease in recombination within these devices. This chapter also presents the use of Sb2S3 in the meso-superstructured configuration. This device architecture showed consistently higher voltages suggesting that in this architecture, charge transport occurs through the absorber and not the mesoporous scaffold. Chapters 6 and 7 focus on the use of hybrid organic-inorganic perovskites in photovoltaic devices. In Chapter 6 the mixed halide, lead-based perovskite, CH3NH3PbI3-xClx is employed in a planar heterojunction device architecture. The effects of Lewis base passivation on this material are investigated by determining the photoluminescence (PL) lifetimes and quantum efficiencies of treated and untreated films. It is found that passivating films of this material using Lewis bases causes an increase in the PLQE at low fluences as well as increasing the PL lifetime. By globally fitting these results to a model the trap densities are extracted and it is found that using these surface treatments decreases the trap density of the perovskite films. Finally, these treatments are used in complete solar cells resulting in increased power conversion efficiencies and an improvement in the stabilised power output of the devices. Chapter 7 describes the materials synthesis and characterisation of the tin-based perovskite CH3NH3SnI3 and presents the first operational, lead-free perovskite solar cell. The work presented in this thesis describes significant advances in the field of hybrid solar cells, specifically with regards to improvements made to the nanostructured electrode, and the development and implementation of more highly absorbing sensitizers. The improvements discussed here will prove to be quite important in the drive towards exploiting solar power as a clean, affordable source of energy.

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Mathiazhagan, Gayathri [Verfasser], and Stefan [Akademischer Betreuer] Glunz. "Interfacial analysis of perovskite solar cells using sub-cells." Freiburg : Universität, 2020. http://d-nb.info/1221523961/34.

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Hassler, Julia. "Mesoporous metal oxides for perovskite solar cells." Thesis, Uppsala universitet, Molekyl- och kondenserade materiens fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-263064.

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Wojciechowski, Konrad. "Electron selective contact in perovskite solar cells." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:0fa3b171-4db3-43d7-9950-1ef338874376.

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Over the last 4 years, perovskite solar cells emerged as an attractive, highly efficient, and low-cost alternative to established, conventional photovoltaic technologies. The power conversion efficiency of these devices recorded an unprecedented rise, currently exceeding certified values of 20%. This thesis covers a number of technological advancements which lead to improved photovoltaic performance, as well as vital insight into some more fundamental aspects of the perovskite device operation. The focus of this body of work is primarily directed towards the electric contact in the PV stack which is responsible for electron collection. The motivation of the study presented here is given in Chapter 1, and includes a brief summary of the current energy landscape. Chapter 2 introduces the theoretical background of photovoltaic technology, starting from the basics of semiconductor physics, through to the principles of solar cell operation, as well as some characteristic properties of the perovskite materials. Details of the experimental methods used in this study are reported in Chapter 3. Chapter 4 reports the development of a low temperature process (sub-150 °C) for the manufacture of perovskite solar cells. Dispersions of pre-synthesised, highly crystalline TiO2 nanoparticles were used as an electron selective contact, which eliminated the high temperature sintering step. Chapters 5, 6 and 7, report the interface modification of an n-type contact, resulting in a substantially improved device operation and suppression of hysteresis phenomenon which is characteristic of perovskite photovoltaics. Fullerene-based materials have been found to make excellent electronic contact with halide perovskite materials, and are shown to be far superior to commonly used metal oxides. The facilitated electron collection allows enhancements in the photovoltaic performance of these devices. Furthermore, the organic layers used in this study can be processed at low temperatures. Finally, the development of transparent conductive electrodes based on silver nanowires is presented in Chapter 8. The fabricated electrodes exhibit low sheet resistance, high degree of transparency, and can be processed at low temperatures, allowing them to be compatible with processing on flexible substrates and multi-junction architectures. The application of silver nanowires in different perovskite solar cell architectures is also reported.

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Hoerantner, Maximilian. "Novel device architectures for perovskite solar cells." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:bb0ebbb0-5743-45fa-a69a-3848dc2018bb.

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The aim of the work presented in this thesis is to study the opto-electronic properties of semi-conducting perovskite materials when being used in unconventional solar cell device configurations. Being a young technology, perovskites as solar cell materials have seen an unparalleled rise in the research community which has driven the fastest performance inflation to power conversion efficiencies competing with the ones of long established single crystalline technologies. The ability to process perovskites inexpensively makes them the new hope in the fight against climate change. Herein device architectures were developed with a special focus on potential commercial applications. Initially the work in this thesis has been motivated by the interest in crystal growth and morphology of perovskite thin-films, which has led to the study of confined crystal growth within microstructures. Controlling the crystal domain geometry enabled the fabrication of enhanced semi-transparent devices. More efforts were directed into the improvement of specifically neutral colour semi-transparent devices, which could be improved via a simple treatment of selectively attaching shunt-blocking layers. Furthermore, a back-contacted perovskite device design was introduced, which allows not only for the fabrication of a new type of perovskite solar cell, but also represent a great material testing platform to study perovskite and electrode characteristics. This led to the discovery of charge transport distances, that exceed those of other thin-film devices. Finally, perovskite-on-silicon tandem solar cell designs were analysed through a rigorous optical model to estimate the expected real world energy yield from such systems. Important implications include the fact that two terminal tandem solar cells come close to four-terminal configurations and can overall compete, in relative terms, well with established single junction silicon cells.

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Liang, Xinxing. "Synthesis of perovskite nanocrystals and their applications in perovskite solar cells." Thesis, University of Bath, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.767584.

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Perovskite solar cells are a very promising photovoltaic technology which was first reported in 2009 and developed very rapidly. The crystallisation within perovskite films is highly dependent on processing environments, such as temperature, humidity, atmosphere, even light, which makes the fabrication of perovskite solar cells rather lab-dependent and poorly reproducible. One strategy to overcome this problem is to develop a controlled synthesis of perovskite nanocrystals which can then be ordered into films in a separatestep. In this thesis, optimisation of planar perovskite solar cells is carried out by the engineering of perovskite film fabrication methods. Different deposition methods along with different process factors such as solvents, temperature and precursor recipes are compared. One step spin-coating method with the recipe of MAI:PbCl2=3:1 gives the best PCE of 12.1 ± 0.7 % in air with controlled humidity of < 35%, showing high reliability and reproducibility. Doping of TiO2 layers with Zn2+, Sn4+ and Nb5+ ions are carried out to investigate the impacts of doping ions in different valence states on the electron-transporting properties of TiO2 ETLs. The different doping ions shift the flat band potential differently. Zn2+ largely negatively shifts the flat band potential, whereas Nb5+ positively shifts and Sn4+ barely changes the flat band potential of TiO2. the Zn-doping of the TiO2 ETL decreases the performance of the cells. However, when a thin layer of Zn-doped TiO2 is deposited on top of the pristine TiO2 layer as interlayer, the cell efficiency is slightly improved. Following the cell optimisation, to achieve better control over the crystallisation process, a facile flow reactor is developed for the synthesis of MAPbX3 perovskite nanocrystals at low temperature, which are further used for perovskite solar cells. The nanocrystals show narrow size distribution, good emissive properties and high stability. The bandgap of the nanocrystals was easily tuned between 485-745 nm by changing the halide composition. The photoluminescence of the MAPbI3 NCs in the first supernatant can also be tuned by changing the process parameters such as temperature, residence time and ligand concentration. However the impacts are more complex in the second supernatant in toluene with the appearance of multiple peaks in the PL spectra. It could be resultedfrom the formation of smaller NCs due to the reprecipitation of the incompletely removed reactants when added into toluene, or the fragmentation of the NCs upon dispersion into toluene, but better understanding is still needed. In the last part of the thesis, the synthesised MAPbI3 nanocrystals are investigated in perovskite solar cell applications. They have been applied as interlayers at the perovskite HTM interface, where they improved the stability of the devices towards moisture. The nanocrystals and their bulk by-products are also used as active light-absorbing layers for perovskite solar cells, delivering the best PCEs of 0.51% and 1.2% respectively, and notably showing outstanding water resistance. Further improvements in the cell performance could potentially be achieved by the removal of the insulating long chain ligands using effective ligand exchange treatments.

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Almora, Rodríguez Osbel. "Hysteresis and Capacitive Features of Perovskite Solar Cells." Doctoral thesis, Universitat Jaume I, 2020. http://hdl.handle.net/10803/669272.

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In the present work, anomalous distortions occurring in the current-voltage characteristic of perovskite solar cells (PSCs), usually called J-V curve hysteresis, are studied by several methods. This includes dynamic direct current (DC) mode J-V experiments and impedance spectroscopy (IS) analyses in dark and under illumination. The J-V curves of PSCs were measured under different conditions showing capacitive hysteretic currents. This is related with low frequency excess capacitance in the IS spectra. These two features are correlated with the response of mobile ions in space charge regions close to the interfaces. The large values of capacitance under illumination in the sub-Hz regime were explained in terms of mobile ions space charges and chemical capacitances assuming a proportionality between the number of ionized/activated mobile ions and the concentration of charge carriers and photon fluence. En el presente trabajo se estudian por varios métodos las distorsiones anómalas en la característica de corriente-voltaje de las celdas solares de perovskita (PSC), típicamente llamada histéresis de J-V. Esto incluye experimentos dinámicos de J-V en modo de corriente continua (DC) y análisis de espectroscopía de impedancia (IS) en oscuridad y bajo iluminación. Las curvas J-V en oscuridad de las PSCs exhiben corrientes capacitivas, relacionadas con un exceso de capacitancia de baja frecuencia en los espectros de IS. Estas dos características están correlacionadas con la respuesta de iones móviles en regiones espaciales de carga hacia las interfaces. Los grandes valores de capacitancia bajo iluminación a frecuencias por debajo de las unidades de Hz se explicaron en términos de regiones de cargas espaciales de iones móviles y capacitancias químicas, suponiendo una proporcionalidad entre el número de iones móviles ionizados/activados y la concentración de portadores de carga y flujo de fotones.

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Wang, Jacob Tse-Wei. "Investigation of interface behaviour on perovskite solar cells." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:9b81f5bf-1c5a-40c1-8abe-2978bd44853e.

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Historically, the interfaces and charge transportation layers dictate the performance in heterojunction solar cells. This thesis addresses the interface behaviours and the interfacial layers within perovskite solar cells (PSCs), and provides insights and practicable solutions to facilitate the realisation of efficient PSCs. To achieve efficient charge collection with interlayer fabricated with low-temperature processes, a graphene-TiO2 nanocomposite is demonstrated; By investigating the carrier transport, we found the insertion of graphene improved the electron collection efficiency with its high surface area and ballistic carrier conduction properties, and in conjunction with pre-synthesised TiO2, we have successfully circumvented the need for high-temperature annealing, enabling the whole device to be fabricated at under 150 °C. While the anomalous hysteresis behaviour which is widely observed in regular PSCs structure is a significant problem, the quest of stable PSCs seems to be answered by the use of inverted PSCs structures. We show a detailed development of inverted PSCs which are deconstructed layer by layer. Numerous approaches have been tailored to improve interfaces, and energy levels between layers, leading to an efficient and hysteresis-free perovskite solar cells. Lastly, an in-depth study of impurity doping is investigated using Al3+. The doping with small metal ions in the perovskite precursor has been found to influenced the crystallisation and optoelectronic properties of the perovskite crystals. Here, for the first time, the correlation between reduced structural crystal defects is clearly linked to enhanced photovoltaic properties, with the best performance for the lowest electronic disorder in the CH3NH3PbI3 crystal.

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Hambsch, Mike, Qianqian Lin, Ardalan Armin, Paul L. Burn, and Paul Meredith. "Efficient, monolithic large area organohalide perovskite solar cells." Royal Society of Chemistry, 2016. https://tud.qucosa.de/id/qucosa%3A36282.

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Solar cells based on organohalide perovskites (PSCs) have made rapid progress in recent years and are a promising emerging technology. An important next evolutionary step for PSCs is their up-scaling to commercially relevant dimensions. The main challenges in scaling PSCs to be compatible with current c-Si cells are related to the limited conductivity of the transparent electrode, and the processing of a uniform and defect-free organohalide perovskite layer over large areas. In this work we present a generic and simple approach to realizing efficient solution-processed, monolithic solar cells based on methylammonium lead iodide (CH₃NH₃PbI₃). Our devices have an aperture area of 25 cm² without relying on an interconnected strip design, therefore reducing the complexity of the fabrication process and enhancing compatibility with the c-Si cell geometry. We utilize simple aluminum grid lines to increase the conductivity of the transparent electrode. These grid lines were exposed to an UV-ozone plasma to grow a thin aluminum oxide layer. This dramatically improves the wetting and film forming of the organohalide perovskite junction on top of the lines, reducing the probability of short circuits between the grid and the top electrode. The best devices employing these modified grids achieved power conversion efficiencies of up to 6.8%.

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Yang, Fengjiu. "Architecture design for highly efficient perovskite solar cells." Kyoto University, 2019. http://hdl.handle.net/2433/244572.

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Cacovich, Stefania. "Electron microscopy studies of hybrid perovskite solar cells." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/276753.

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Over the last five years hybrid organic-inorganic metal halide perovskites have attracted strong interest in the solar cell community as a result of their high power conversion efficiency and the solid opportunity to realise a low-cost as well as industry-scalable technology. Nevertheless, several aspects of this novel class of materials still need to be explored and the level of our understanding is rapidly and constantly evolving, from month to month. This dissertation reports investigations of perovskite solar cells with a particular focus on their local chemical composition. The analytical characterisation of such devices is very challenging due to the intrinsic instability of the organic component in the nanostructured compounds building up the cell. STEM-EDX (Scanning Transmission Electron Microscopy - Energy Dispersive X-ray spectroscopy) was employed to resolve at the nanoscale the morphology and the elemental composition of the devices. Firstly, a powerful procedure, involving FIB (Focus Ion Beam) sample preparation, the acquisition of STEM-EDX maps and the application of cutting edge post-processing data techniques based on multivariate analysis was developed and tested. The application of this method has drastically improved the quality of the signal that can be extracted from perovskite thin films before the onset of beam-induced transformations. Morphology, composition and interfaces in devices deposited by using different methodologies and external conditions were then explored in detail by combining multiple complementary advanced characterisation tools. The observed variations in the nanostructure of the cells were related to different photovoltaic performance, providing instructive indications for the synthesis and fabrication routes of the devices. Finally, the main degradation processes that affect perovskite solar cells were probed. STEM-EDX was used in conjunction with the application of in situ heating, leading to the direct observation of elemental species migration within the device, reported here for the first time with nanometric spatial resolution. Further analyses, involving a set of experiments aimed to study the effects of air exposure and light soaking on the cells, were designed and performed, providing evidence of the main pathways leading to the drastic drop in the device performance.

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RAFIZADEH, SAEID. "Interface Engineering for Highly Efficient Perovskite Solar Cells." Doctoral thesis, Università degli studi di Pavia, 2020. http://hdl.handle.net/11571/1317086.

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After decades of research, crystalline silicon technology dominates the global photovoltaic market by 92%. To gain market share from crystal silicon solar cells, emerging photovoltaic technologies have to demonstrate a combination of high power conversion efficiency (PCE), easy and cost-effective manufacturing processes and long-term stability. Recent researches suggest that organic-inorganic halide perovskites have the potential to meet these conditions and become competitive in the marketplace. The work presented here is comprised of an experimental study on the fabrication of perovskite solar cells using a two-step hybrid evaporation-spincoating method. Solution processing enables easy fabrication processes with possibility of band-gap tuning for tandem application while vacuum basted methods offer the advantages of deposition on non-planar surfaces like light trapping pyramidal textured structures, interesting for tandem configuration on high efficiency silicon solar cells. The hybrid two-step evaporation-spincoating deposition method, gains benefit from both solution processing and vacuum based deposition advantages while not suffering from the drawback of hazardous solvents consumption in solution processing. With maturing of the fabrication methods, a deepened understanding of which factors determine PCE, becomes more and more important for further improvements. Especially understanding of the crystallization and the layer ripening is crucial as those determine the occurring of defect centers that could limit performance. Accordingly, the role of excess PbI2 in perovskite structures and its impact on crystallization quality, optoelectronic properties and photovoltaic performance of different perovskite solar cells is studied in this thesis. It is found that a higher concentration of remnant and unconverted PbI2 correlates with smaller and stronger interconnected grains, as well as with an improved optoelectronic performance of the solar cells with higher efficiencies and the mitigation of hysteresis. Moreover, the issue of ''Interface Engineering'' at the perovskite top and bottom interfaces is addressed. Optimization of the charge carrier transport layers improved the optoelectronic and photovoltaic parameters. The impact of different transparent conductive oxides is also investigated in this thesis. The optical and electrical parameters of the perovskite absorber deposited on FTO and ITO transparent conductive oxides are compared. This is interesting especially for the tandem applications where the interface engineering is crucial for decreasing the parasitic losses. Tandem perovskite on silicon architecture is presented as an outlook for this thesis. Implementation of perovskite absorber fabricated by hybrid method atop highly efficient silicon bottom cell would lead to the efficiencies beyond theoretical efficiency limit of single junction solar cells. After decades of research, crystalline silicon technology dominates the global photovoltaic market by 92%. To gain market share from crystal silicon solar cells, emerging photovoltaic technologies have to demonstrate a combination of high power conversion efficiency (PCE), easy and cost-effective manufacturing processes and long-term stability. Recent researches suggest that organic-inorganic halide perovskites have the potential to meet these conditions and become competitive in the marketplace. The work presented here is comprised of an experimental study on the fabrication of perovskite solar cells using a two-step hybrid evaporation-spincoating method. Solution processing enables easy fabrication processes with possibility of band-gap tuning for tandem application while vacuum basted methods offer the advantages of deposition on non-planar surfaces like light trapping pyramidal textured structures, interesting for tandem configuration on high efficiency silicon solar cells. The hybrid two-step evaporation-spincoating deposition method, gains benefit from both solution processing and vacuum based deposition advantages while not suffering from the drawback of hazardous solvents consumption in solution processing. With maturing of the fabrication methods, a deepened understanding of which factors determine PCE, becomes more and more important for further improvements. Especially understanding of the crystallization and the layer ripening is crucial as those determine the occurring of defect centers that could limit performance. Accordingly, the role of excess PbI2 in perovskite structures and its impact on crystallization quality, optoelectronic properties and photovoltaic performance of different perovskite solar cells is studied in this thesis. It is found that a higher concentration of remnant and unconverted PbI2 correlates with smaller and stronger interconnected grains, as well as with an improved optoelectronic performance of the solar cells with higher efficiencies and the mitigation of hysteresis. Moreover, the issue of ''Interface Engineering'' at the perovskite top and bottom interfaces is addressed. Optimization of the charge carrier transport layers improved the optoelectronic and photovoltaic parameters. The impact of different transparent conductive oxides is also investigated in this thesis. The optical and electrical parameters of the perovskite absorber deposited on FTO and ITO transparent conductive oxides are compared. This is interesting especially for the tandem applications where the interface engineering is crucial for decreasing the parasitic losses. Tandem perovskite on silicon architecture is presented as an outlook for this thesis. Implementation of perovskite absorber fabricated by hybrid method atop highly efficient silicon bottom cell would lead to the efficiencies beyond theoretical efficiency limit of single junction solar cells.

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Schoenauer, Mathilde. "Enhancing perovskite solar cells through upconversion nanoparticles insertion." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS369.

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Les énergies renouvelables peuvent à la fois répondre au besoin croissant en énergie tout en répondant à la nécessité de décarboniser l’énergie. La ressource énergétique solaire est quasi infinie (la terre reçoit plus d’énergie solaire en une heure qu’elle en consomme en un an) mais reste pourtant peu exploitée. Les cellules solaires hybrides à base de perovskite connaissent depuis les années 2000 un essor sans précédent dans le monde de la recherche en technologies solaires. Elles appartiennent à la catégorie des films minces, et nécessitent donc bien moins de matière première que les cellules au silicium, pour le moment largement majoritaires sur le marché. Cependant, elles n’absorbent pas au-delà de 800 nm, et tout l’infra-rouge est donc non converti par ce type de cellules solaires. Ce doctorat a pour but d’augmenter l’absorption dans l’infrarouge et donc le rendement de la cellule solaire. Pour cela, on y place des particules appelées nanoparticules d’upconversion, qui convertissent un rayonnement infrarouge en visible. Il s’agit d’un phénomène d’absorption simultané de deux photons. Cet effet ayant un rendement assez faible, il convient de le booster par l’insertion de nanoparticules métalliques afin de pouvoir bénéficier de l’augmentation de l’intensité du champ électromagnétique dans leur voisinage proche (effet dit plasmonique). En combinant les deux types de particules on parvient à augmenter l’absorption des particules à upconversion, et en les plaçant tous deux dans une cellule solaire, on augmente donc son rendement Renewable energies represent nowadays one of the keys that can tackle at the same time energy supply needs and a sustainable environmental behavior. Photovoltaic devices convert the energy of sunlight into electricity, and solar energy remains one of the most common renewable energy sources. In the search for cost-effective solar cells, the recently discovered solution-processable hybrid organic-inorganic perovskites are considered as one of the most important candidates. They belong to the category of thin-film technologies and require much less and as abundant resource than Si. One limiting parameter of such photovoltaic devices is however the absorption of low-energy photons (wavelength over 800 nm, the near-infrared range). In order to address this specific loss of sub bandgap photons’ absorption, this PhD thesis aims to develop plasmonic-enhanced upconversion approaches to extend the spectral sensitivity of organo-metal halide perovskite solar cells to the near-IR spectrum. Near-infrared-to-visible up-conversion fluorescent materials can be used to widen the part of the spectrum used for electric current generation. Two low-energy photons are added up in order to give a higher energy photon. However, this effect has a rather small efficiency. This effect being quite inefficient, the idea is to combine those particles with metallic nanoparticles, that have the property to enhance electromagnetic field intensity at a certain wavelength (this is called plasmonic effect). By combining both types of particles, we thus enhance the activity of up-conversion materials (higher emission). Once implemented in a perovskite solar cell, this increases its efficiency

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Mirabelli, Alessandro James. "Highly efficient monolithic Perovskite/Silicon bifacial tandem solar cells." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20369/.

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Perovskite solar cells have been the focus of photovoltaics research in this past decade. Owing to their many favorable properties - like low cost solution processability, tunable bandgap and high efficiency, they have seen much attention in various types of solar cell designs. A promising technology has coupled perovskite cells with another semiconductor material in monolithic tandem solar cells, reaching record efficiencies of 29.15%. However, these kinds of devices require current matching condition to maximize the output of solar cells, making their fabrication challenging. Here, we propose the innovative bifacial tandem configuration to overcome current matching limits between the two sub-cells, by collecting photons from the surrounding environment, i.e. albedo. The extra light shining on our silicon bottom cell boosts the photogenerated current above monolithic tandem values. We show that the current density gain is more pronounced in perovskite solar cells with a narrow bandgap, 1.59 eV, than those with a wider one 1.7 eV. In other words, current matched tandems show little to no increase in efficiency with the extra albedo, while mismatched cells exhibit the most power, reaching up to ~28% in the best scenario. To give more credit to our work, we report outdoor data gathered in various locations around the world, and we show how different albedos have distinct effects on bifacial tandems.

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Rueda, Delgado Diana Paola. "Charge carrier dynamics and interfaces in perovskite solar cells." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/667466.

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Organometal halide perovskites for solar cells are hybrid semiconductors that recently have caught the attention of the scientific community due to its excellent performance and attractive optical properties. Since then, they have been used in solar cells, LEDs, and lasers, although the mechanisms by which such good performances are obtained are not known completely. This dissertation presents a study of the optical characteristics of perovskites for thin-film solar cells. Due to their small thickness, the morphology of the layer is sensitive to manufacturing parameters. In this way, the manufacturing process is optimized, trying to improve its characteristics. Among the challenges perovskites pose for implementation, the lack of stability during operation is one of the most relevant. Therefore, in this dissertation, the reasons for stability losses are also studied. For this purpose, interlayers are used, which introduce changes in the interface of the perovskite with the electron extraction layer, and with the initial purpose of reducing the hysteresis in the current-voltage curve. In addition to reducing it, they stabilize the power extracted from the solar cell under illumination. The effects of degradation on the characteristics of solar cells allow the identification of their origins and propose a solution to avoid or delay damage to the perovskite layer. With this in mind, it is established that the problem of stability does not only lie within the perovskite layer but also in the contact between the layers and in the charge transport within the perovskite solar cell. Careful control of these interfaces, then, facilitates the achievement of stable performances and long lifetimes of the perovskite solar cells. Las perovskitas organometálicas de haluros para celdas solares son un tipo de semiconductor híbrido que recientemente ha atrapado la atención de la comunidad científica debido a su excelente desempeño y atractivas propiedades ópticas. Desde entonces, han sido utilizadas en celdas solares, LEDs y lasers, a pesar de que los mecanismos por los cuales se obtienen tan buenos desempeños no son completamente conocidos. Con esta disertación se presenta un estudio sobre las características ópticas de la perovskitas para su utilización en celdas solares de películas delgadas. Debido a su delgado grosor, la morfología de la capa es sensible a los parámetros de fabricación. De manera que se optimiza el proceso de fabricación tratando de mejorar sus características. Entre los retos que presentan las perosvkitas para su implementación, la falta de estabilidad durante su funcionamiento es uno de los más relevantes. Entonces en este dissertationo se estudian también las razones por las que se presenta pérdidas de estabilidad. Para esto se utilizan entrecapas, que introducen cambios en la interfaz de la perovksite con la capa extractora de electrones, y con el propósito inicial de reducir la histéresis en la curva de corriente-voltaje. Además de reducirlo, estabilizan la potencia extraída de la celda solar bajo iluminación. Los efectos de la degradación en las características de las celdas solares nos permiten identificar sus orígenes y presentar propuestas para evitar o retardar los daños a la capa de perovskita. Teniendo esto en cuenta, podemos establecer que el problema de la estabilidad no radica sólo dentro de la perovskita, pero también en el contacto entre las capas y en el transporte de carga dentro de la celda solar de perovskita. El control cuidadoso de estas interfaces, entonces, permite la obtención de un rendimiento estable y una vida larga del dispositivo. Organometallhalogenid-Perowskite sind hybride Halbleiter, die in jüngster Zeit aufgrund ihrer hervorragenden Halbleitereingeschaften und attraktiven optischen Eigenschaften die Aufmerksamkeit der Wissenschaft auf sich gezogen haben. Seitdem wurde die exzellente Eignung dieser Materialklasse für verschiedenste opto-elektrische Anwendungen wie z.B. Solarzellen, LEDs und Lasern unter Beweis gestellt. Die physikalischen Mechanismen, die die Grundlage für diese einzigartigen, qualitativ Hochwertigen Eigenschaften bilden, sind jedoch noch weitgehend unbekannt. Dieses Manuskript stellt eine Studie über die optischen Eigenschaften von Perowskitfilmen für den Einsatz in Dünnschichtsolarzellen dar, die mit dem Spin-Coating-Verfahren hergestellt wurden. Aufgrund des geringen Dicken der Perowskitschichten ist deren Morphologie empfindlich gegenüber kleinen Variationen der Fertigungsparameter. Deshalb muss der Herstellungsprozess durch Feinjustierung dieser Parameter optimiert werden, um hocheffiziente Solarzellen herzustellen. Eine der größten Herausforderungen für die Kommerzialisierung der Perowskitphotovoltaik ist neben der Herstellung durch die mangelnde Stabilität des Wirkungsgerades während des Betriebs gegeben. Daher werden in der vorliegenden Arbeit zusätzlich die Gründe für diese Stabilitätsverluste untersucht. Zu diesem Zweck werden zusätzliche Nanoschichten zwischen der Perowskit- und der Elektronenextraktionsschicht appliziert, die nicht nur eine Reduzierung der Hysterese in der Strom-Spannungskurve bewirken, sondern die Leistung der Solarzelle unter Sonneneinstrahlung stabilisieren. Der Vergleich der Stabilität von Solarzellen mit und ohne zusätzlichen Zwischenschichten ermöglicht Rückschlüsse auf die Ursache der Degradationsmechanismen. Ein Hauptresultat dieser Stabilitäts- bzw. Degradationsstudie ist die Tatsache, dass ein Großteil des beobachteten Effizienzverlustes nicht durch die Perowskitdegradation innerhalb des Filmes, sondern vielmehr durch die Instabilität der Grenzflächen des Perowskits mit den Extraktionsschichten zustande kommt. Die Grenzflächendegradation erzeugt eine Barriere für den Ladungstransport durch die Erhöhung der lokalen „Trap-Dichte“. Basierend auf dieser Erkenntnis eröffnet die sorgfältige Modifikation der Grenzflächen innerhalb der Solarzelle vielfältige Möglichkeiten, um eine stabile Betriebsleistung der Solarzelle über längere Zeiten durch Vermeidung bzw. Verzögerung der Degradation zu erzielen

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Carrier, Nathalie. "Indoor photovoltaics with Perovskite solar cells and nanostructured surfaces." Thesis, KTH, Tillämpad fysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-181078.

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Saliba, Michael. "Plasmonic nanostructures and film crystallization in perovskite solar cells." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:fdb36a9e-ddf5-4d27-a8dc-23fffe32a2c5.

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The aim of this thesis is to develop a deeper understanding and the technology in the nascent field of solid-state organic-inorganic perovskite solar cells. In recent years, perovskite materials have emerged as a low-cost, thin-film technology with efficiencies exceeding 16% challenging the quasi-paradigm that high efficiency photovoltaics must come at high costs. This thesis investigates perovskite solar cells in more detail with a focus on incorporating plasmonic nanostructures and perovskite film formation. Chapter 1 motivates the present work further followed by Chapter 2 which offers a brief background for solar cell fabrication and characterisation, perovskites in general, perovskite solar cells in specific, and plasmonics. Chapter 3 presents the field of plasmonics including simulation methods for various core-shell nanostructures such as gold-silica and silver-titania nanoparticles. The following Chapters 4 and 5 analyze plasmonic core-shell metal-dielectric nanoparticles embedded in perovskite solar cells. It is shown that using gold@silica or silver@titania NPs results in enhanced photocurrent and thus increased efficiency. After photoluminescence studies, this effect was attributed to an unexpected phenomenon in solar cells in which a lowered exciton binding energy generates a higher fraction of free charge. Embedding thermally unstable silver NPs required a low-temperature fabrication method which would not melt the Ag NPs. This work offers a new general direction for temperature sensitive elements. In Chapters 6 and 7, perovskite film formation is studied. Chapter 6 shows the existence of a previously unknown crystalline precursor state and an improved surface coverage by introducing a ramped annealing procedure. Based on this, Chapter 7 investigates different perovskite annealing protocols. The main finding was that an additional 130°C flash annealing step changed the film crystallinity dramatically and yielded a higher orientation of the perovskite crystals. The according solar cells showed an increased photocurrent attributed to a decrease in charge carrier recombination at the grain boundaries. Chapter 8 presents on-going work showing noteworthy first results for silica scaffolds, and layered, 2D perovskite structures for application in solar cells.

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Fuentes, Pineda Rosinda. "Triphenylamine-based hole transport materials for perovskite solar cells." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31410.

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The rapid development in perovskite solar cells (PSC) has generated a tremendous interest in the photovoltaic community. The power conversion efficiency (PCE) of these devices has increased from 3.8% in 2009 to a recent certified efficiency of over 20% which is mainly the product of the remarkable properties of the perovskite absorber material. One of the most important advances occurred with the replacement of the liquid electrolyte with a solid state hole conductor which enhanced PCE values and improved the device stability. Spiro-OMeTAD (2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)- 9,9'-spirobifluorene) is the most common hole transport material in perovskite solar cells. Nevertheless, the poor conductivity, low charge transport and expensive synthetic procedure and purification have limited its commercialisation. Triphenylamines (TPA) like Spiro-OMeTAD are commonly employed due to the easy oxidation of the nitrogen centre and good charge transport. Other triarylamines have similar properties to Spiro-OMeTAD but are easier to synthesise. The aim of this doctoral thesis is to investigate different types of hole transport materials in perovskite solar cells. Three different series of triphenylamine-based HTM were designed, synthesised, characterised and studied their function in perovskite solar cells. A series of five diacetylide-triphenylamine (DATPA) derivatives (Chapter 3) with different alkyl chain length in the para position was successfully synthesised through a five step synthesis procedure. A range of characterisation techniques was carried out on the molecules including; optical, electrochemical, thermal and computational methods. The results show that the new HTMs have desirable optical and electrochemical properties, with absorption in the UV, a reversible redox property and a suitable highest occupied molecular orbital (HOMO) energy level for hole transport. Perovskite solar cell device performances were studied and discussed in detail. This project studied the effect of varying the alkyl chain length on structurally similar triarylamine-based hole transport materials on their thermal, optical, electrochemical and charge transport properties as well as their molecular packing and solar cell parameters, thus providing insightful information on the design of hole transport materials in the future. The methoxy derivative showed the best semiconductive properties with the highest charge mobility, better interfacial charge transfer properties and highest PCE value (5.63%). The use of p-type semiconducting polymers are advantageous over small molecules because of their simple deposition, low cost and reproducibility. Styrenic triarylamines (Chapter 4) were prepared by the Hartwig-Buchwald coupling followed by their radical polymerization. All monomers and polymers were fully characterised through electrochemical, spectroscopic and computational techniques showing suitable HOMO energy levels and desirable optoelectrochemical properties. The properties and performance of these monomers and polymers as HTMs in perovskite solar cells were compared in terms of their structure. Despite the lower efficiencies, the polymers showed superior reproducibility on each of the device parameters in comparison with the monomers and spiro-OMeTAD. Finally, star-shaped structures combine the advantages of both small molecules, like well-defined structures and physical properties, and polymers such as good thermal stability. Two star-shaped triarylamine-based molecules (Chapter 5) were synthesised, fully characterised and their function as hole-transport materials in perovskite solar cells studied. These materials afford a PCE of 13.63% and high reproducibility and device stability. In total this work provided three series of triarylamine-based hole transport materials for perovskite solar cells application and enabled a comparison of the pros and cons of different design structures: small-molecule, polymeric and star-shaped.

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Eperon, Giles E. "Active layer control for high efficiency perovskite solar cells." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:1fa78aab-7479-4fe2-8192-e1be1d12c171.

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The work documented in this thesis concerns the control and modification of semiconducting perovskite thin films for their use in perovksite solar cells (PSCs). PSCs are a promising new thin-film technology, offering both high solar to electricity conversion efficiencies and cheap fabrication costs. Herein, the boundaries of perovskite solar cell research are pushed further by tackling several challenges important to the field. Initially, this work focuses on understanding why the best PSCs made so far have been mesostructured devices, with the perovskite infiltrated into a scaffold. It is shown that this can be seen as simply a fabrication aid; without the scaffold, thin films easily dewet from the substrate. By understanding the crucial parameters important in carefully controlling this dewetting, it is minimised, and it is shown that scaffold-free planar heterojunction devices with high efficiencies can be fabricated. This work leads on to the next section; the development of semi-transparent perovskite solar cells. In their present state, PSCs cannot compete with silicon as stand-alone modules. Here, the morphological control has been leveraged to realise a different embodiment â semi-transparent perovskite devices for use in building-integrated photovoltaics. Competitive efficiency and transparency are demonstrated. Moreover, a hybrid self-tinting power-generating window concept is fabricated, by combining the photovoltaic and electrochromic technologies. In the third section of the thesis, the limitations of the most studied perovskite material, methylammonium lead halide, are addressed: its overly wide bandgap and thermal instability. To address these, the chemical constituents of the perovksite are altered, and the development of more efficient and more stable materials are reported. These are likely to be important for perovskite modules to pass international certification requirements for commercialisation. Finally, an in-depth study on the effect of ambient moisture, relevant for considering scale-up and the fabrication environment needed, is carried out. It is shown that the presence of some moisture during film fabrication allows a reduction of defect states in the perovskite material, enhancing device performance and film quality.

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Liu, Guoduan. "Fabrication and Characterization of Planar-Structure Perovskite Solar Cells." UKnowledge, 2019. https://uknowledge.uky.edu/ece_etds/137.

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Currently organic-inorganic hybrid perovskite solar cells (PSCs) is one kind of promising photovoltaic technology due to low production cost, easy fabrication method and high power conversion efficiency. Charge transport layers are found to be critical for device performance and stability. A traditional electron transport layer (ETL), such as TiO2 (Titanium dioxide), is not very efficient for charge extraction at the interface. Compared with TiO2, SnO2 (Tin (IV) Oxide) possesses several advantages such as higher mobility and better energy level alignment. In addition, PSCs with planar structure can be processed at lower temperature compared to PSCs with other structures. In this thesis, planar-structure perovskite solar cells with SnO2 as the electron transport layer are fabricated. The one-step spin-coating method is employed for the fabrication. Several issues are studied such as annealing the samples in ambient air or glovebox, different concentration of solution used for the samples, the impact of using filter for solutions on samples. Finally, a reproducible fabrication procedure for planer-structure perovskite solar cells with an average power conversion efficiency of 16.8%, and a maximum power conversion efficiency of 18.1% is provided.

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Chen, Chien-Hua, and 陳建樺. "Development of large scale carbon-based mesoscopic perovskite solar cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/97ss8h.

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碩士 國立交通大學 應用化學系碩博士班 107 This thesis is focused on the device engineering and optimization for the large scale carbon-based mesoscopic perovskite solar cells (CMPSC). For optimal design and development of large scale CMPSC, the small modules of CMPSC were investigated in detail. We introduced laser etching machine and dispenser in the fabrication process to achieve highly precise manufacturing of large-area modules with 15.12 cm2 area. Initially the PCE can reach 7.47% for one-step method and 8.01% for slow crystallization. The second part is focused on further optimizing the module design, and further improvement of the process steps according to the commercialization requirements. Finally, PCE can reach 7.92% for one-step with a very high voltage of 9.3 volts for large-area carbon electrode perovskite solar cell. The third part is the application of these large scale carbon electrode perovskite solar modules with emphasis on energy storage. Here we showed that they can be used in commercial applications both under 1 SUN standard illumination or indoor light.

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Chang, Hung-Ming, and 張宏銘. "esign and scale-up for carbon-based mesoscopic perovskite solar cells." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/uud8hb.

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碩士 國立交通大學 應用化學系碩博士班 105 My thesis is focused on large scale and polymer-template carbon-based mesoscopic perovskite solar cells (CMPSC). For design and development of large scale CMPSC, the small modules of CMPSC were well studied. The VOC and power conversion efficiencies (PCE) have respectively reached 3.3 V and 6.64% of the devices with 19 cm2 area. For a 2*2 cm2 CMPSC devices, effects of different penetration temperatures as well as the different solvent ratios both were well studied. The PCE can reach 9.77% with actual working area of 3 cm2; moreover, the encapsulated CMPSC long-term stability can reach over 2200 hours. The second part device engineering of polymer-template CMPSC, the polymer-template TiO2 was introduced, in order to improve the filtration of precursor solution. Moreover, one more NiO mesoporous layer was inserted between Al2O3 and carbon layer, which that served as hole extraction layer. The device structure of 1000nm polymer-template TiO2 / 500nm Al2O3 / 500nm NiO / Carbon showed the best PCE, 14.32% (average is 13.98 ± 0.34%) and IPCE integration current is up to 18.55 mA cm-2 with the modified two-step deposition method.

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Sutanto, Albertus Adrian, and 陳凱翔. "Application of Solvent Assisted Crystallization Technique in Mesoscopic and Planar Heterojunction Perovskite Solar Cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/37547813715203371141.

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碩士 國立臺灣科技大學 化學工程系 103 Solar cells based on methyl ammonium lead iodide perovskite as light absorbers have gained much attention owing to its high efficiency and low fabrication cost. Two device structures namely mesoscopic nanocomposite and planar heterojunction have achieved high efficiencies. These superior conversion efficiencies were achieved through extensive manipulation of the device components like perovskite composition, TiO2 layers and/or interface engineering. These complicated methods are essential to get the best efficiency but quite challenging to reproduce. A one-step solvent assisted crystallization technique is introduced in the mesostructured perovskite solar cells for the first time. Solvent assisted crystallization technique is performed by drop-casting of chlorobenzene on spinning substrate with CH3NH3PbI3 perovskite precursor solution dissolved in DMF. Analysis of the film morphology using scanning electron microscopy revealed that the perovskite layer deposited by solvent assisted crystallization technique consists of an extremely uniform and dense perovskite crystalline grains. Mesoscopic nanocomposite perovskite solar cells fabricated by solvent assisted crystallization technique demonstrate the highest power conversion efficiency of 16.92% and an average power conversion efficiency of 15.41% (s.d. ± 0.75) calculated for 60 devices under standard AM 1.5G illumination. As a comparison, planar heterojunction perovskite solar cells were fabricated using the same condition resulting in best performing device with the power conversion efficiency of 13.33% (s.d. ± 1.19) and an average power conversion efficiency of 10.43% over 12 devices. The hysteresis effect is also reduced by a large extend due to the mesoscopic architecture compared to the planar heterojunction devices. As far as our knowledge, the work from this thesis has led to achieve the second best efficiency reported for a mesoscopic nanocomposite perovskite solar cell based on spiro-OMeTAD as a hole transporting material without any extensive manipulations on the chemical compositions and exhausted device optimization by using all commercially available ingredients. These results provide an important insight towards the understanding of the significance of solution processed device in the realization of highly efficient, highly consistent, and low-cost perovskite solar cells.

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Lin, Yu-Pei, and 林宇培. "Application of hybrid organic cations in mesoscopic carbon electrode tin-based perovskite solar cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/a5hgw4.

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碩士 國立交通大學 工學院加速器光源科技與應用學位學程 107 In this thesis, we employed the hybrid organic cations into the mesoscopic carbon electrode tin-based perovskite solar cells. The cations we used are formamidinium iodide (FAI) and 2-hydroxyethylammonium iodide (HEAI). By adjusting the amount of HEAI, we were able to tune the optical properties of the perovskite due to the changing of crystal structure. For our reference perovskite i.e. FASnI3, the performance suffers from huge leakage current and the obtained efficiency is only 0.9% due to the poor penetration, rapid crystallization and energy level mismatch. However, by applying the hybrid perovskite to our mesoscopic carbon electrode solar cell, the device performance reached 2.5%. Additionally, the variation in device performance with the alteration of HEAI amount was investigated in details. To further improve our device performance, we used diethyl ether as antisolvent to facilitate the crystal growth in our device. By mixing solvent to improve the penetration of the perovskite precursor and adding various percent of ethylenediammonium diiodide (EDAI2) as additives to modify the crystallinity of the perovskite, the device performance successfully reached to 3.2±0.26% and 3.7% for the champion cell. Hence, in this work we successfully demonstrated a novel strategy to further enhance the photovoltaic performance of pristine FASnI3 from 0.9% to 3.7% using 40% of HEAI as a substitute for FAI with 3% of EDAI2 as additives.

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Tsai, Cheng-Min, and 蔡政緡. "Control of Crystal Structures and Energy Levels for Mesoscopic Carbon Electrode Tin-based Perovskite Solar Cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/yq5c3w.

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博士 國立交通大學 應用化學系分子科學碩博士班 107 The objective of this thesis is about studying each role within three-dimensional ABX3 (A = organic cations, B = Sn2+ or Pb 2+, X = halides) perovskites, and further to modify the crystal structures and energy levels for mesoscopic carbon electrode tin-based perovskites solar cells. In the first part, we report the synthesis and characterization of alloyed Sn-Pb methylammonium (MA) mixed-halide perovskites (CH3NH3SnyPb1-yI3-xClx) to extend light harvesting toward the near infrared region for carbon-based mesoscopic solar cells, which are free of organic hole-transport layers. SnCl2 plays a vital role to modify the lattice structure of the perovskite illustrating anomalous optical and optoelectronic properties. As the concentration of SnCl2 increasing, the variation of the band gap and band energy differed from those of the SnI2 precursor. The CH3NH3SnyPb1-yI3-xClx devices showed a photovoltaic performance enhanced on increasing the proportion of SnCl2 until y = 0.75, consistent with the corresponding potential-energy levels. Moreover, the device's stability also promoted, which that demonstrated intrinsic stability. In the second part, we synthesized and characterized methylammonium (MA) mixed tri-halide tin perovskites (MASnIBr2-xClx) for carbon-based mesoscopic solar cells. Upon changing SnCl2/SnBr2 ratios yielded tin perovskites with three halides (I, Br and Cl) co-crystallized inside the tin-perovskite crystals for x  0.5 according to the stoichiometric ratios of the precursors of MASnIBr2-xClx. When the SnCl2 proportion was equal to or greater than 50 % (x  1), phase separated and generated two crystal system of MASnI3-yBry and MASnCl3-zBrz, according to the stoichiometric proportions of their precursors, confirmed with the corresponding XRD analysis. A device with MASnIBr1.8Cl0.2 (SnCl2 = 10 %) showed the best photovoltaic performance with JSC/mA cm-2 = 14.0, VOC/mV = 380, FF = 0.573 and PCE/% = 3.1, showing great reproducibility and long-term stability. This work first time showed the I/Cl can cocrystallize within one crystal structure as halide sites occupied by more than 50% bromine. In the final part, alcohol-based bi-functional ammonium cations, 2-hydroxyethylammonium (HEA+), HO(CH2)2NH3+, has been introduced into the formamidinium (FA+) tin-based perovskites (HEAxFA1-xSnI3) as a light absorber for carbon-based mesoscopic solar cells. We synthesized perovskites HEAxFA1-xSnI3 via mixing different ratios of HEAI/FAI with equimolar SnI2 precursors. We found that HEA+ cations play a key role to control the crystal structures; the lattice structures changed from orthorhombic (x = 0) to rhombohedral (x = 0.2－0.4) with higher symmetry. Once x increased to 0.6－1.0, tin and iodide vacancies were formed to generate 3D-vacant perovskites (HEAxFA1-xSn0.67I2.33, x ≥ 0.6) with a tetragonal structure. For perovskite made of HEAI 100 %, the crystal structures exist two phases – a 3D-vacant perovskite (kinetic-preferred phase, HEASn0.67I2.33) and a 2D-layered perovskite (thermodynamic-preferred phase, HEA2SnI4), which can be synthesized via controlling of the rate of crystal growth. Four new single crystals of the perovskites － one 3D structure at HEAI 40 %, one 3D-vacant structure at 80 % and two 2D structures at 100 % are reported herein. After optimization of device performance, which that demonstrated efficiency η = 3.7 % with great stability and reproducibility.

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Chang, Bo-Chih, and 張博智. "Development of Mesoscopic Carbon-based Electrodes for Lead-free Perovskite Solar Cells and Large-scale Applications." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/h55pk2.

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碩士 國立交通大學 應用化學系分子科學碩博士班 107 This thesis aim to develop lead-free and large scale carbon-based mesoscopic perovskite solar cells (CMPSC). As a matter of lead-free CMPSC, we introduced different cations into copper-based perovskite contributed to the small modules and confirm (DOP)2CuBr4 has better power conversion efficiencies (PCE). We could controlled the filltration and crystallization behavior of perovskite within porous TiO2/Al2O3 layers by adjusting the precursor solution amount and annealing temperature. In order to boost the short circuit current density (JSC) and device performances we modified the thickness of Al2O3 layer and inserted NiO hole extraction layer between Al2O3 and carbon layer. The PCE of devices were improved from 0% to 0.07% after optimization. The second part regard to module design of large scale CMPSC. The module adapted 2.34cm2 with 6 cells in series. One step and two steps approaches were implemented under ambient environment, and thus PCE achieved 9.21% and 10.36%, respectively, with corresponding open-circuit voltage (VOC) of 5.4V and 5.7V. Ultimately, we combined super capacitor with large scale module to drive appliance under room light and demonstrated that it can be a function of internet of thing (IoT).

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Lin, Wei-Jhih, and 林威志. "Influence of the Titanium Dioxide Nano-particles Size on the Performance of Mesoscopic Perovskite Solar Cell." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/yayf56.

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碩士 國立中央大學 化學工程與材料工程學系 105 In recent years, organic–inorganic perovskite based solar cells have got sub-stantial attention due to their low fabrication cost and excellent photovoltaic properties. Although the power conversion efficiency of the perovskite solar cells have achieved over than 20%, anomalous hysteresis in current–voltage curves remain as major challenge, which cause inaccuracy of the PCE measurements. In this work, we use hydrothermal method to synthesize high purity anatase titanium dioxide nanoparticles by controlling the reaction conditions of the auto-clave. We investigate the particle size effect of titanium dioxide mesoporous layer on conventional mesoscopic perovskite solar cells, and with spray pyroly-sis deposition method to prepare titanium dioxide dense layer and through the lithium (LiTFSI) doping to optimize titanium dioxide mesoporous layer, im-prove the efficiency of electronic transmission and reduce the hysteresis of the conventional mesoscopic perovskite solar cells in the measurement effectively. The best performance of the cells is 22 nm particle size, its power conversion ef-ficiency of reverse scan is up to 18.46%, forward scan is 16.37%, and the hyste-resis index is decrease to 0.092. In addition, we verify the particle size effect of titanium dioxide mesoporous by the system of fully printable mesoscopic perovskite solar cells, the results are match to the conventional structural tendency. It is proved that the particle size of titanium dioxide in the electron transport layer is the key to the photoelectric conversion characteristics of the conventional structure perovskite solar cells. In-creasing the specific surface area of titanium dioxide mesoporous layer improves the contact area between the perovskite layer and the titanium dioxide mesopo-rous layer effectively. The rate of the electron injection from perovskite into tita-nium dioxide becomes faster, resulting in higher injection quantum efficiency after the electron-hole separation. This system has the best performance of the components prepared with 22 nm particle size of titanium dioxide, the efficiency of cells up to 10.86% after optimization. It is stable for 450 hours in ambient air and still retain 96% of original efficiency.

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Jacobs, Daniel Anthony. "Device Modelling of Perovskite Solar Cells." Phd thesis, 2018. http://hdl.handle.net/1885/151935.

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This thesis is primarily concerned with the electrical characterization and modelling of perovskite solar cells. Perovskite cells are a new player in the photovoltaic arena with several intriguing properties. One of these is the presence of intrinsic mobile ions which make these semiconductors simultaneously ionic conductors at room temperature. The presence of mobile ions is significant in that it leads to a number of transient behaviours in optoelectronic measurements, including nominally simple current-voltage measurements where the phenomena are broadly labelled as aspects of ``I-V hysteresis''. The first two-thirds of this thesis describes our work on extended drift-diffusion models which incorporate the presence of mobile ions into the conventional equations of semiconductor physics. These allow us to uncover mechanistic explanations for a variety of transient behaviours which are broadly caused by coupling between electronic and ion dynamics. The first third (Chapter 2) deals with hysteresis in the form of rate-dependent I-V sweeps: a selection of unusual measurements of this type is presented including a temporary enhancement in open-circuit voltage following prolonged periods of negative bias, dramatically S-shaped current-voltage sweeps, decreased current extraction following positive biasing or ``inverted hysteresis'', and non-monotonic transient behaviours in the dark and the light. This initial study is supplemented with a more in-depth investigation of inverted hysteresis and its correlation with band-alignment. The second third (Chapter 3) delves deeper into electrical characterization with a first-principles study of electrical impedance spectroscopy. We focus on accounting for features in the measured capacitance spectrum (sufficient for a full account of the total impedance due to the Kramers-Kronig relations) of standard-structure (non-inverted) perovskite cells. Here our models make clear the necessity of distinguishing fundamental contributions to the measured capacitance due to charging, from those due to currents delayed by slow processes such as ion migration. With this distinction clearly established we provide a detailed account of all the major features observed in impedance measurements of these cells, including the exotic and previously puzzling appearance of giant photo-induced capacitance, loop features and negative capacitance. The final part of this thesis in Chapter 4 concerns the integration of perovskite cells into tandem arrangements with a partner such as the crystalline silicon cell. Of relevance to any thin-film solar cell, and to 4-terminal tandem cells in particular, is the specifications of its transparent conductor layers. We analyze transparent conductor requirements under different regimes of metallization (the addition of metallic bus-bars or fingers). Here a key parameter is the minimal achievable wire width, which dictates the necessary tradeoff between transparency and conductivity in the underlying transparent conductor. We identify \SI{30}{\micro \metre} as a critical width below which many emerging transparent conducting layers such as carbon nanotubes and graphene become competitive with state-of-the-art transparent conductive oxides such as ITO for a stand-alone perovskite cell. We also discuss a novel strategy for integrating perovskite and Si cells into a single monolithic structure without the need for a tunnel junction or recombination layer. This is identified as being possible due to the presence of interfacial sub-gap states which can facilitate high-conductivity ohmic contact between TiO$_2$ and p-type Si, and has significant advantages in terms of reducing optical losses and processing steps.

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Hu, Yu-Tung, and 胡雨彤. "Photo-physical Properties of Perovskite and Mesoporous Perovskite Solar Cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/10467435291808561210.

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碩士 國立交通大學 應用化學系碩博士班 104 This thesis is divided into two parts; the first part reports results from studies on perovskite (MAPbI3) by using temperature dependent photoluminescence spectroscopy and x-ray diffraction techniques. The photoexcited emission peak positions, intensity, and full width at half maximum (FWHM) were recorded when the temperature was scanned from 300 K to 10 K. The second part demonstrates the fabrication of perovskite solar cells and the enhancement of cell performance by the combination of improving the perovskite filling in TiO2 layer and surface passivation. From the XRD spectra, a phase transition from the tetragonal phase (at room temperature) to the orthorhombic phase begin to take place when the temperature of perovskite was cooled down to ~ 150 K. Clear PL signals originated from the orthorhombic phase were observed around 110 K ~ 120 K. With increased temperature, the luminescence peak of the tetragonal phase first showed slightly blue-shifted from 1.596 eV to 1.598 eV at 40 K and then was red-shifted to 1.57 eV at 130 K. Above 130 K, the energy peak was again blue-shifted to 1.61 eV with temperature increased toward 300K. The luminescence peak of the orthorhombic phase showed only slightly blue-shifted from 1.66 eV to 1.67 eV with temperature increased from 10 K to 120 K. Narrowing of the FWHM of the luminescence peak of the tetragonal phase from 105 meV to 49 meV was observed with increased temperature from 10 K to 120 K. Above 120 K, the FWHM began to broaden and reached 94 meV at 300 K. The FWHM of the luminescence peak of the orthorhombic phase decreased from 43 meV to 38 meV with decreased temperature from 100 K to 10 K. In the scanning electron microscope images, nano scale grains with an average size of ~ 10 nm were observed in the MAPbI3 thin film. We speculate that, due to the presence of the nano grains, localized states were induced within the energy gap of MAPbI3 due to the quantum confinement effect. The observed temperature dependent behavior in photoluminescence spectra, which is similar to those observed in the self-assembly semiconductor quantum dots, was attributed to the presence of localized states induced by the MAPbI3 nano scale grains. The mesoporous perovskite solar cells were demonstrated with an initial efficiency of 6.5% by using a two-step deposition method. By spinning PbI2 for two times to provide a better perovskite loading, the efficiency was improve to 8%. The efficiency was further improved to 9.7% by using the silanol to passivate the uncoordinated halide on the interface, which led to reduced surface recombination and enhanced carrier transport.

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Tsai, Chih-Han, and 蔡芷涵. "The perovskite solar cells: perovskite materials and hole transport materials." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/k7gtbv.

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碩士 國立臺灣科技大學 化學工程系 105 For perovskite solar cells (PVSCs), this thesis studies the hole transport material (HTM) and perovskite materials. In the first part of this study, we make the CH3NH3PbI3 perovskite solar cells with P3HT polymer or spiro-OMeTAD small molecule as HTM. We study the influence of tBP and LiTFSI additives in HTM on the performance of PVSCs, including the hysteresis effect. And, the second part is about the perovskite material CH3NH3PbI3. We try to prepare partial-iodide replaced perovskite materials, i.e., CH3NH3PbI3-x(SCN)x, CH3NH3PbI3-x(N3)x, and CH3NH3PbI3-x(AlCl4)x. Materials properties and corresponding solar cell performance are studied, compared, and analyzed.

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Lin, Jin-Tai, and 林金泰. "Decay Mechanism of Perovskite Solar Cell and Development of Lead-free Perovskite Solar Cells." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/43wua4.

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博士 國立臺灣大學 化學研究所 106 Initially, we investigated the degradation of perovskite solar cells under operating situations through in situ X-ray diﬀraction and in situ X-ray absorption spectroscopies, which revealed that lead hydroxide iodide (PbIOH), a new phase that has not previously been identiﬁed as the degradation product of perovskite solar cells, was formed as an end decomposition product inside the cell. The formation of PbIOH could break the interface inside and be the key reason behind the problem of reduced cell life. In second part, we replaced the lead perovskite in carbon-electrode based solar cell with tin perovskite. In third part, we use a zwitterion additive to improve the film morphology of tin perovskite active layer by retarding nucleation process, and the efficiency of corresponding solar cells with 4 cm2 area can achieve 2.1%. In addition, the additive also significantly enhances the stability of device. The final part is about tin perovskite quantum material. We have successfully prepared tin perovskite nanoplate which demonstrates excellent quantum yield of 6.4%, narrow full width at half maximum (FWHM) of 37 nm, and wide tunability window.

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LIN, GUAN-YOU, and 林冠佑. "Dye Sensitized Solar Cells and Perovskite Solar Cells studied by Impedance Spectroscopy." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/gkaf6y.

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碩士 東海大學 應用物理學系 106 Photoelectrochemical dye-sensitized solar cells (DSCs) have attracted much interest in the field of sustainable green energy. However, their counter electrodes (CEs) usually fabricated by the noble metal Pt. To obtain the alternative Pt-Free CEs for DSCs is desirable for the wide deployment of DSCs. Alternative materials have been found as counter electrodes for DSCs, and the most widely used materials are carbon-based materials. In this study, carbon paste (CP) was used to replace Pt as the CEs of DSCs, and it was subjected to calcination at different thermal treatment temperatures to observe its effect on the performance of DSCs. The experimental results showed that when the thermal treatment temperature was 300 ℃, the overall conversion efficiency of cells can reach 4.9%, which is comparable to 5.7% of the cells with counter electrode of platinum. After thermal treatment, crystalline quality of CP was improved, resulting in the decrease of series resistance of cells and the increase of the work function of CP. We also showed that the reduction rate of triiodide is significantly enhanced due to the increase of surface area of CP and the energy matching between the reduction potential of triiodide and the work function of CP. Due to own the tunable band gap, high absorption coefficient, low non-radiation carrier recombination, perovskite materials received significant attention by many researchers in recent. There are many researchers used perovskite materials as light-harvesting materials for solar cells. This research cooperates with the Department of Chemical and Materials Engineering of Chang Gung University to provide a perovskite solar cells with CH3NH3PbI3 as light-harvesting material. In this study, perovskite solar cells were measured inside the glove box under low humidity and oxygen content. The impedance spectroscopy is used to observe the effects of different laser wavelengths and different laser power densities on perovskite solar cells. The first arc at higher frequencies is related to the perovskite layer, the second arc at lower frequencies is due to the recombination between the perovskite and TiO2 layer. The experimental results showed that whether Rp and Rrec decrease with the increase of the laser power density. In addition, because 532 nm excite electrons to the high conduction band, and the short electron extraction time at this conduction band results in the high photoconductance response to 532 nm illumination.

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YenVu, Thi Hai, and 武海燕. "Carbon-based Electrodes for Perovskite Solar Cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/47224779375197551289.

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Yu-HsuanYang and 楊玉軒. "Porous counter electrode based perovskite solar cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/47108639978717851080.

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Duarte, Eduardo Manuel Ribeiro. "Low-Cost Thin Film Perovskite Solar Cells." Master's thesis, 2018. http://hdl.handle.net/10362/47632.

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Perovskite is a class of materials named after their characteristic crystal structure, presenting excellent optoelectronic properties. These properties (particularly, ambipolar charge transport) allow these materials to integrate solar cells with and without the addition of selective layers, like Electron-Transport-Layer and Hole-Transport-Layer, possessing also the ability to be fabricated using simple, non-expensive, solution processing techniques, like Spin-Coating. Coupled with its facile production, the steep rise in SC efficiency over the last years, makes these materials a strong candidate to replace Silicon in the photovoltaic market, both in solid-state and flexible devices. Despite its many advantages, Perovskite SC still face considerable costs regarding processing conditions and HTL materials. By fabricating these devices under ambient air conditions and using Copper(I) Thiocyanate as the material for the HTL, the fabrication costs are significantly reduced. To further lower fabrication cost, Methylammonium Chloride is studied as a replacement for Methylammonium Iodide in Perovskite precursor solution fabrication. Using this solution, crystalline films were obtained, studying several deposition parameters, and the best reported ones, should provide a starting point for further optimization under similar fabrication conditions. The main goal for this work was the optimization of SC, using Spin-Coating technique, keeping the devices as low-cost as possible. Improving Perovskite film quality is detrimental to enhance SC performance, which is why efforts were made to minimize film degradation during Perovskite film fabrication and HTL deposition steps. Due to the hygroscopic nature of the organic component in Perovskite films, the influence of humidity levels was tested, and methods to reduce thin film degradation via humidity exposure were also evaluated. Overall, device optimization was successful, with Perovskite films reaching >95% bulk density and the champion device presenting PCE of 2.65%, with Jsc of 15.11 mA/cm2 and Voc of 0.701V.

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Emami, Seyedali. "Advanced hermetic encapsulation of perovskite solar cells." Doctoral thesis, 2020. https://hdl.handle.net/10216/129436.

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Figueroa, Xerman Amaro. "Techno-economic analysis of perovskite solar cells." Master's thesis, 2022. https://hdl.handle.net/10216/140748.

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Emami, Seyedali. "Advanced hermetic encapsulation of perovskite solar cells." Tese, 2020. https://hdl.handle.net/10216/129436.

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Chang, Ning-Yi, and 張寧詒. "Impedance Spectroscopic Analysis of Perovskite Solar Cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/23519992457309650391.

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碩士 中原大學 物理研究所 104 Since 2009 to nowadays, Perovskite solar cells have a good development. Perovskite solar cells from mesoporous structures to heterojunction plane p-i-n structures have something improved. In addition to production process becoming simpler also have better efficiency. We report that flat, uniform thin films of this material can be deposited by a one-step, solvent-induced, fast crystallization method involving spin coating of a DMF solution of CH3NH3PbI3 followed immediately by exposure to chlorobenzene to induce crystallization. In the first experiment, we set different delay time (2 s/ 4 s /6 s) to drop the poor solvent. And we observed their surface topography, electrical measurement, and electrochemical impedance. In the second experiment, there are four different conditions on the Perovskite thin films. Added DMSO or not and two different spin coating transfers speeds (5000 rpm, 6000rpm). And then we observed their surface topography, electrical measurement, and electrochemical impedance. In the first experiment, we found there are many holes on the surface which delay time is 2 seconds. And its average efficiency achieves 1.17%. In addition, a little holes on the surface which delay time is 4 seconds. However, its average efficiency achieves 9.32%. At last, there are a flat thin film when the delay time is 6. Although its average efficiency only achieves 7.68%, but there are many samples’ efficiency achieve more than 10%. In the second experiment, we found that adding DMSO contribute to improving open circuit voltage and fill factor. And current density is higher when rotating speed at 6000 rpm. The electrochemical impedance is measured without illumination and the potential is 0V. We found the efficiency is higher and the recombination resistance is higher. Applied bias voltage is higher and the recombination resistance is smaller.

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Teng, Tsung-Chang, and 鄧琮璋. "The study of Perovskite Structure Solar Cells." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/32453555161265158343.

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碩士 中原大學 化學研究所 102 This study is based on perovskite material - CH3NH3PbI3 as a light absorbing material. In a traditional dye-sensitized solar cell, the organic dye is often used as a photosensitizer. In the view of the organic dyes are high priced and difficult to be synthesized, the present experiments synthesized inorganic light absorber to instead of the traditional organic dye photosensitizers. In the first part of the study, we introduce how to prepare perovskite structure material, and confirm using X-ray diffraction spectroscopy and Thermogravimetric analysis. It did not require high temperature and energy-consuming equipment to synthesize the perovskite materials for the use in solar cells. In the second part of the study, we have employed the perovskite materials in the solar cells and measured its photovoltaic properties. We used solution deposition method and sequential deposition method to deposit the perovskite structure material on the TiO2 film to prepare the solar cell with the structure of traditional DSSC and liquid electrolyte. The results of this experiment achieved =4.93%, more than 80% of the photoelectric conversion efficiency of the traditional dye-sensitized solar cell efficiency (=5.86%). In the third part of the study, since the perovskite materials are susceptible to the moisture and decompose easily in the electrolyte solvent, leading to a rapid decline of the performance. Preparation of all-solid solar cells was done to replace the traditional dye-sensitized solar cell to avoid the disadvantages of electrolyte. Hole-conducting materials (HTMs) such as spiro-MeOTAD in perovskite solar cells are demonstrated to optimize the efficiency.

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Chen, Wei Cheng, and 陳威丞. "Synthesis and Characteristics of Novel Perovskite Layers in Perovskite Solar Cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/56406830482644632721.

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Ting, Chang-Chieh, and 丁昶介. "Perovskite Film Defect Control and Preparing High Efficiency Perovskite Solar Cells." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/zc6bz2.

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碩士 國立中央大學 化學工程與材料工程學系 107 In recent years, perovskite solar cells have developed rapidly, but there are still many problems to overcome in the commercialization. In terms of perovskite materials, they are susceptible to light and moisture, causing the degradation of perovskites, in which defects play an important role in perovskite films. How to prepare low-defect perovskite films is the focus of this article. This article will divided into two parts. The first part is the preparation of low-defect perovskite films by spin coating process, discussing the morphology of perovskite MAPbI3 films and power conversion efficiency of solar cells under delayed annealing process. Optimize the best delay annealing condition for sixty minutes in room temperature. Then we focus on the effects after doping potassium iodide and iodine. Potassium ions can increase the crystallinity of perovskites, let absorption red shifts, reduce energy band gaps, occupy perovskite interstitial defects, and reduce defect density. The last part, iodine reacts with iodide ions in the solution to produce triiodide ions(I3-), which improves deep-level defects in perovskite films, increases electrical conductivity and carrier mobility. The champion efficiency reach 19.36 %. The second part is the preparation of the mixed surfactant perovskite by doctor blade coating. Different concentrations of non-ionic surfactant Tween20 and Tween60 are added into the perovskite precursor solution for blade coating process. Discuss the difference in crystallization, compare the effects of two surfactants on blade coating on perovskite films and effort on performance of perovskite solar cells.

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