Dissertations / Theses: 'CH3NH3PbI3'

1

Wehrenfennig, Christian. "Ultrafast spectroscopy of charge separation, transport and recombination processes in functional materials for thin-film photovoltaics." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:1f812413-4a2f-418f-a7fd-d749e88cc2e1.

Full text

Abstract:

Dye-sensitized solar cells (DSSCs) and perovskite solar cells are emerging as promising potential low-cost alternatives to established crystalline silicon photovoltaics. Of the employed functional materials, however, many fundamental optoelectronic properties governing photovoltaic device operation are not sufficiently well understood. This thesis reports on a series of studies using ultrafast THz and photoluminescence spectroscopy on two classes of such materials, providing insight into the dynamics of charge-transport and recombination processes following photoexcitation. For TiO₂-nanotubes, which have been proposed as easy-to-fabricate electron transporters for DSSCs, fast, shallow electron trapping is identified as a limiting factor for efficient charge collection. Trapping lifetimes are found to be about an order of magnitude shorter than in the prevalently employed sintered nanoparticles under similar excitation conditions and trap saturation effects are not observed, even at very high excitation densities. In organo-lead halide perovskites - specifically CH₃NH₃PbI₃ and CH₃NH₃PbI_3-xCl_x, which have only recently emerged as highly efficient absorbers and charge transporters for thin-film solar cells, carrier mobilities and fundamental recombination dynamics are revealed. Extremely low bi-molecular recombination rates at least four orders of magnitude below the prediction of Langevin's model are found as well as relatively high charge-carrier mobilities in comparison to other solution-processable materials. Furthermore a very low influence of trap-mediated recombination channels was observed. Due to a combination of these factors, diffusion lengths reach hundreds of nanometres for CH₃NH₃PbI₃ and several microns for CH₃NH₃PbI_3-xCl_x. These results are shown to hold for both, solution processed and vapour-deposited CH₃NH₃PbI_3-xCl_x and underline the superb suitability of the materials as absorbers in solar cells, even in planar heterojunction architectures. The THz-frequency spectrum of the conductivity of the investigated perovskites is consistent with Drude-like charge transport additionally exhibiting weak signatures of phonon coupling. These coupling effects are also reflected in the luminescence of CH₃NH₃PbI_3-xCl_x, where they are believed to be the cause of the observed homogeneous spectral broadening. Further photoluminescence measurements were performed at temperatures between 4 K and room temperature to study the nature of recombination pathways in the material.

APA, Harvard, Vancouver, ISO, and other styles

2

Lee, Heejae. "Analysis of Current-Voltage Hysteresis and Ageing Characteristics for CH3NH3PbI3-xClxBased Perovskite Thin Film Solar Cells." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX009/document.

Full text

Abstract:

Les perovskites organiques-inorganiques en halogénures de plomb sont des matériaux très prometteurs pour la prochaine génération de cellules solaires avec des avantages intrinsèques tels que leur faible coût de fabrication (grande disponibilité des matériaux de base et leur mise en œuvre à basse température) et leur bon rendement de conversion photovoltaïque. Cependant, les cellules solaires pérovskites sont encore instables et montrent des effets d'hystérésis courant-tension délétères. Dans cette thèse, des résultats de l’analyse physique de couches minces de pérovskite à base de CH3NH3PbI3-xClx et de cellules solaires ont été présentés. Les caractéristiques de transport électrique et les processus de vieillissement ont été étudiés avec différentes approches.Dans une première étape, la synthèse du matériau pérovskite a été optimisée en contrôlant les conditions de dépôt des films en une seule étape telles que la vitesse de rotation (6000 rpm) de la tournette et la température de recuit des films (80 °C). Dans un second temps, des cellules solaires perovskites à base de CH3NH3PbI3-xClx ont été fabriquées en utilisant la structure planaire inversée et caractérisées optiquement et électriquement.Grace à l’utilisation de la spectroscopie optique à décharge luminescente (GDOES), un déplacement des ions halogénures a été observé expérimentalement et de façon directe sous l’application d’une tension électrique. Une longueur de diffusion ionique de 140 nm et un rapport de 65% d'ions mobiles ont été déduits. Il est montré que l'hystérésis courant-tension dans l'obscurité est fortement affectée par la migration des ions halogénures provoquant un écrantage substantiel du champ électrique appliqué. Nous avons donc trouvé sous obscurité un décalage de la tension à courant nul jusque 0,25 V et un courant de fuite jusque 0,1 mA / cm2 en fonction des conditions de mesure. Grâce aux courbes courant-tension en fonction de la température, nous avons déterminé la température de transition de la conductivité ions/électrons à 260K et analysé les résultats expérimentaux en utilisant l'équation de Nernst- Einstein donnant une énergie d'activation de 0.253 eV pour les ions mobiles.Enfin, le processus de vieillissement de la cellule solaire a été étudié avec des mesures optiques et électriques. Nous avons déduit que le processus de vieillissement apparaît d'abord à la surface des cristaux de pérovskite ainsi qu’aux joints de grains. Les mesures GDOES nous indiquent que les caractéristiques électriques des cellules pérovskites sont perdues par une corrosion progressive de l'électrode supérieure en argent causée par la diffusion des ions iodures
Organic-inorganic lead halide perovskites are very promising materials for the next generation of solar cells with intrinsic advantages such as a low-cost material due to the availability of source materials and low-temperature solution processing as well as a high power conversion efficiency of the sunlight. However, perovskite solar cells are still unstable and show deleterious current-voltage hysteresis effects. Inthis thesis, analyses of CH3NH3PbI3-xClx based perovskite thin films and solar cells are presented. The electrical transport characteristics and the ageing processes are investigated using different approaches.The synthesis of the halide perovskite materials is optimized in a first step by controlling the deposition conditions such as annealing temperature (80°C) and spinning rate (6000 rpm) in the one step-spin-casted process. CH3NH3PbI3-xClx based perovskite solar cells are then fabricated in the inverted planar structure and characterized optically and electrically in a second step.Direct experimental evidence of the motion of the halide ions under an applied voltage has been observed using glow discharge optical emission spectroscopy (GDOES). Ionic diffusion length of 140 nm and ratio of mobile iodide ions of 65 % have been deduced. It is shown that the current-voltage hysteresis in the dark is strongly affected by the halide migration which causes a substantial screening of the applied electric field. Thus we have found a shift of voltage at zero current (< 0.25 V) and a leakage current (< 0.1 mA/cm2) in the dark versus measurement condition. Through the current-voltage curves as a function of temperature we have identified the freezing temperature of the mobile iodides at 260K. Using the Nernst-Einstein equation we have deduced a value of 0.253 eV for the activation energy of the mobile ions.Finally, the ageing process of the solar cell has been investigated with optical and electrical measurements. We deduced that the ageing process appear at first at the perovskite grain surface and boundaries. The electrical characteristics are degraded through a deterioration of the silver top-electrode due to the diffusion of iodides toward the silver as shown by GDOES analysis

APA, Harvard, Vancouver, ISO, and other styles

3

Zhang, Jie. "Roles of the n-type oxide layer in hybrid perovskite solar cells." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066634/document.

Full text

Abstract:

Le soleil offre une ressource abondante et inépuisable d’énergie. Le photovoltaïque est la technologie la plus importante pour rendre l'énergie solaire utilisable car les cellules solaires photovoltaïques recueillent le rayonnement solaire et le convertissent en énergie électrique. Les cellules solaires à colorant (DSSC) ont été très étudiées en raison de leur faible coût, d’une technique de fabrication facile et une grande versatilité. Un dispositif classique DSSC comprend une photo-anode à colorant, une contre-électrode et un électrolyte contenant un couple redox et des additifs. Pour améliorer la stabilité de ces dispositifs, le remplacement de l'électrolyte liquide par des matériaux solides transporteur de trous a été étudié pour donner ce que l’on appelle des cellules solaires à colorant solides (ssDSSCs). Récemment, les pérovskites hybrides organique/inorganiques ont été introduites dans les systèmes ssDSSCs comme absorbeur de lumière. Les cellules correspondantes, appelées cellules solaires à pérovskite (PSC) ont ouvert une nouvelle ère en photovoltaïque en raison du faible coût de ce matériau et la grande efficacité de ces cellules. L'efficacité de conversion de puissance a augmenté de 3,8% en 2009 à un rendement certifié de 20,1% fin 2014. Les composants des cellules solaires à pérovskite comprennent: une couche compacte d'oxyde jouant le rôle de barrière pour les trous photogénérés, une couche de transport des électrons (un semiconducteur de type n), la couche de l’absorbeur de lumière à base de pérovskite d’halogénure de plomb, la couche de transport des trous et le contact arrière. Dans cette thèse, nous nous sommes concentrés sur la préparation et l’amélioration des propriétés de la couche de transport d'électrons et la couche de pérovskite
Solar energy is one of the most important resources in our modern life. Photovoltaic is the most important technology to render the solar energy usable since photovoltaic solar cells harvest light coming from sun and convert sunlight into electrical energy. Dye sensitized solar cells have gained widespread attention due to their low cost, easy fabrication technique and tunable choice for the device. A traditional DSSC device includes a dye-sensitized photo-anode, a counter electrode and an electrolyte containing a redox couple system and additives. To improve the device stability, the liquid electrolyte replacement by a solid state hole transport material has been studied in so-called solid-state dye sensitized solar cells (ssDSSCs). Recently, an amazing light perovskite absorber was introduced into the ssDSSC system to replace the dye, opening the new field of research. Perovskite solar cells (PSCs) open a new era in photovoltaic due to the low cost of this material and the high efficiency of these cells. The power conversion efficiency has risen from 3.8% to a certified 20.1% within a few years. The components in the perovskite solar cell include: the compact metal oxide blocking layer, the electron transport layer, the lead halide perovskite layer, the hole transport layer and the back contact. In this thesis, we focused on the preparation and improving the properties of the electron transport layer and the perovskite layer

APA, Harvard, Vancouver, ISO, and other styles

4

CHEN, FEIPENG. "Characterization and application of Pb-based organometal halide perovskite." Doctoral thesis, Università degli Studi di Cagliari, 2015. http://hdl.handle.net/11584/266791.

Full text

Abstract:

In the foreseeable future, the global energy consumption is expected to increase significantly. Solar energy, as an alternative form of energy, has gained popularity as a way to solve the greenhouse gas emission and sustainability problem of fossil fuels. This thesis mainly concerns a novel materials system, namely organometal trihalide perovskite, that is currently receiving considerable attention as light absorber in solar cells, due to the promise to obtain significant improvements in the efficiency of solar cells fabricated with very low cost, scalable techniques. The main idea of this thesis is to study the photophysical properties and the mechanisms affecting the performance of solar cells. In chapter 1, the history of solar cell materials will be reviewed briefly. The synthesis and basic characterization are described in chapter 2. In this chapter, it is explained how the methylammonium iodide was synthesized and purified. Perovskite films were fabricated by three different methods, resulting in very different film morphologies. Perovskite structure was confirmed by X-ray diffraction, and CH3NH3PbI3 shows a tetragonal phase with lattice parameters a=b=8.872 Å and c =12.637 Å. The morphology investigation shows that solution spin-casting method produces needle-shaped crystals, leading to a partial surface coverage and limited conductivity. The two-step from solution method was based on spin-casting PbI2 and CH3NH3I solution gradually, creating the perovskite upon reaction of the two compounds. The result is a film with smaller grains and more uniform coverage. Finally, the vapour assisted method, where a PbI2 film is first obtained by spin-casting from solution, then evaporation of CH3NH3I occurs for several hours in N2 atmosphere. A uniform film was achieved by this method with RMS roughness around 38 nm. The optical properties of the CH3NH3PbI3 are investigated in chapter 3. The optical bandgap of it is 1.64 eV, as extracted from the absorption edge, which is higher than the theoretical 1.55 eV. The absorption coefficient exceeds ~105 cm-1 for incident light wavelength shorter than 500 nm. The transient photoluminescence spectroscopy analysis shows that the lifetime of the excitons could be as high as τ = 80 ns under low excitation conditions. As long as the film is processed in such a way that the mean PL lifetime exceeds several nanoseconds at sun illumination, carrier mobility is sufficiently high to guarantee efficient charge collection in the photovoltaic device. In chapter 4, simple planar solar cells are described, which have been fabricated with compact TiO2 as electron transport layer, covered with perovskite as light harvester; poly (3-hexylthiophene- 2,5-diyl) (P3HT) was spin-casted as hole transport layer; at last, transition metal oxide MoO3 or LiF was evaporated onto P3HT as interfacial modifying material, final electrode was a thin layer of Ag. The relationship between TiO2 morphology and the solar cell performance is discussed. The morphology of compact TiO2 appears to be an important factor to influence the photovoltaic, which still needs further understanding in order to obtain better performing devices. The investigation on perovskite morphology indicates that the vapour assisted two-step deposition technique is useful for preparing perovskite films. We rationalize the crystal growth process with the conjecture that the organic and inorganic components have an efficient reaction by vapour intercalation into the PbI2 film. The resulting film has full surface coverage, microscale grain size and uniform grain structure. The investigation on interfacial modification shows that the solar cell with MoO3 as modification material has excellent performance with a PCE of 7.95%. And the solar cell with LiF as modification material has good performance with a Jsc of 21.73 mA/cm2. Both of the two materials have positive affection to the solar cell. The MoO3 is a proper material for modifying the interface between the electrode and hole transporting layer, which could replace the ITO in a heterojunction solar cell. And the LiF could decrease the work function of the metal contact, which may increase the transporting ability and increase the compatibility of the metal electrode. The investigation implies that the interface engineering is very important to the device science.

APA, Harvard, Vancouver, ISO, and other styles

5

Zhang, Xingmo. "Synthesis, characterization and photocatalyst application of CH3NH3PbBr3 single crystals." Thesis, The University of Sydney, 2020. https://hdl.handle.net/2123/22427.

Full text

Abstract:

Organic-inorganic hybrid perovskites, which combine the advantages of superior optoelectronic properties and solution-processed manufacturing, have emerged as the new class of revolutionary materials with great potential for various practical applications. Encouraged by the longer carrier diffusion length, higher carrier mobility and better optoelectronic properties than their polycrystalline counterparts, increasing research effort has been focused on the preparation and optimization of perovskite single crystals using various solution-synthesis techniques for controlling the morphology and promoting their wide optoelectronic applications. In this regard, further clarifying the microstructure as well as charge carrier transporting behaviors and loss mechanisms within perovskite single crystals will be greatly rewarding, which would further guide to further improve the relevant device performance. Moreover, it would be also of great significance to broaden the device applications of single crystals, considering the excellent optoelectronic properties and their related stability nature and facile processing. In the first work, I synthesized methylammonium lead bromide CH3NH3PbBr3 thin single crystals on Fluorine-doped tin oxide glass (FTO) substrates and Si/SiO2 substrates and characterized their morphology and phase purity, and I found that there are solution residuals on the surfaces and around the single crystals. I further characterized the microstructure and elemental composition, and the charge transport properties of the perovskite thin single-crystals. I found there were two kinds of solution residuals: small perovskite crystals or the mixture of perovskite and PbBr2, which was difficult to be removed and would hinder charge transportation of single-crystalline devices. Hydrogen (H2) production using suitable semiconductors through the photocatalytic water splitting process is a much sought-after technology to reduce greenhouse gases and to further contribute to clean solar hydrogen energy production. To date, it is still a big challenge to find stable semiconductor photocatalysts responding to wide-ranged light illumination. Recently, lead halide perovskites have emerged as promising candidates for the high-performance photocatalysts beyond various other optoelectronic devices owing to their excellent optoelectronic properties. However, most of the previous works on perovskite photocatalysts employed the form of polycrystalline thin films, which still suffer from instability due to water and inherent performance. In my second work, we synthesized the high-quality CH¬3NH3PbBr3 single crystals by the inversed-temperature crystallization method and investigated their performance as a photocathode for water splitting with a simple device structure. An optimized perovskite crystal exhibits a good water-splitting photocurrent density of 0.51 mA cm-2 at 0 V vs. Reversible Hydrogen Electrode (RHE) under the white light illumination. Such devices showed improved stability with no obvious decrease over 600 s. Our work highlights the potential of hybrid perovskite single crystals as photocathodes for photocatalysis in neutral solution.

APA, Harvard, Vancouver, ISO, and other styles

6

Pawar, Krantikumar Subhash. "Ab Initio Modeling of an Electron Transport Layer Interface in Hybrid Perovskite Solar Cells." Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1610125331928229.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

DeSantis, Dylan David. "CH3NH3PbBr3-xClx Device Characteristics for Gamma Spectroscopy with Simulations of Real Time Pulse Height Analysis." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1501878848404021.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

CHIU, CHUN-CHANG, and 邱俊彰. "Deposition of CH3NH3PbBr3 and CH3NH3PbI3 Perovskite Nanocrystalline Films by Chemical Bath Deposition for Light-Emitting Diode." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/83xr9m.

Full text

Abstract:

碩士
國立臺南大學
綠色能源科技學系碩士班
107
The research on the photoelectric properties of perovskite materials are rapidly progressing, but perovskite materials are unstable in the atmosphere, so most of the research is done in an inert environment. In this study, colloidal perovskite nanoparticles were synthesized in the atmosphere, and self-assemble CH3NH3PbBr3 and CH3NH3PbI3 perovskite nanocrystalline films by chemical bath deposition, the whole process was completed in non-polar solvents. Our proposed synthesis method different from the high temperature mechanism of the thermal injection method. Finally, the LED elements of CH3NH3PbBr3 and CH3NH3PbI3 with glass/ITO/PEDOT:PSS/CH3NH3PbBr3 or CH3NH3PbI3 /TPBI /LiF /Al structure have a maximum brightness of about 200 and 16.8 cd/m2; the current efficiency is 0.205 cd/A, 0.004 cd/A; electroluminescence wavelength is 520, 688 nm, respectively.

APA, Harvard, Vancouver, ISO, and other styles

9

ShiXian, Guan, and 官世賢. "Carriers transport behavior in perovskite CH3NH3PbI3 transistor." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/99052500127481648750.

Full text

Abstract:

碩士
中原大學
奈米科技碩士學位學程
105
For the issue of environment and renewable energy development, solar cells become significance of energy vision in next generation. It is undoubtedly one of the most popular materials is organic perovskite. Normally, solar cells produce photocurrent by separation of electron-hole pairs in p-n junction. Perovskite has special properties, which has p-n junction without doping impurities into intrinsic material. It''s different from silicon solar cells. In order to find the electrical properties of perovskite''s carrier transport, we measured the characteristic of the field-effect transistor. In field-effect transistor, t the channel carriers can be modulated by Gate voltage. It''s means that the behavior of the carriers in the channel will change when the electric field of the gate is changed. Therefore, the bipolar carrier behavior can be observed by controlling gate voltage. With two direction field of gate, FET present different electrical curve severally. When the organic perovskite is used as the channel material of the field effect transistor, It is expected that the number of carriers in the channel can be regulated by the electric field of gate. It''s could be observed the changes of carrier transport. Because it is usually as the active layer of solar cell which produce electron-hole pairs, it have bipolar carrier transport. Ideally, it would observe the field effect in the organic perovskite channels by different direction gate voltages. We grow organic perovskite thin film on silicon wafer which have already grown silicon dioxide layer and gold electrodes. And gate electrode is highly doped silicon layer at wafer bottom. Finally, it fixed the glass on perovskite film to separate the water and oxygen. It can avoid the reaction between water and sample. From the experimental data, it can be observed that the gate voltage with different direction can both regulate the carrier in the channel. This also means that organic perovskites have bipolar carrier transport. Applying 1 (V) between drain and source, when the gate voltage is positive, we can calculate that the carrier mobility of device is 1.412×10-2 (cm2 V-1s-1). And when the gate is negative, the carrier mobility of device is 9.126×10-4 (cm2 V-1s-1). It had an asymmetric order of magnitude, but indeed bipolar carrier. In addition, in different scanning directions of drain-source voltage, such as from negative to positive and from positive to negative, it has different curve between two sometimes. It has some hysteresis effect when it applied a larger drain-source voltage. And it still showed at a large scanning interval time 1 sec, indicating that it is not the reason of scanning interval time. At this stage, we have confirmed that organic perovskites have bipolar carrier transport at room temperature, and it is curious that device performance of organic perovskite in low-temperature environments. It had report that when the organic perovskite in a low temperature environment, the voltage-current curve close to field-effect transistor, the field-effect by gate voltage will start to become obvious. But the problem is the report only measure down to 78 K, the device performance at lower temperature is a question.

APA, Harvard, Vancouver, ISO, and other styles

10

Widhayani, Dyah Ayu Agustin, and 戴雅妮. "Deposition and Electron Transport Characterization of CH3NH3PbI3 Perovskites." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/3bw2cc.

Full text

Abstract:

碩士
國立交通大學
電子物理系所
105
Due to their high energy conversion efficiencies in solar cells, CH3NH3PbI3 perovskites have attracted much attention in optoelectronic applications. Here we deposit high quality thin films of CH3NH3PbI3 perovskites on Si wafers by using a two-step spin coating method, and we try several methods to make field-effect transistors. In this study, we demonstrate the field-effect behavior, the temperature behavior, and the light illumination behavior of the CH3NH3PbI3 perovskite devices. It is found that the resistance decreases with increasing temperatures, indicating the semiconducting behavior almost without impurity doping in our CH3NH3PbI3 perovskites. On the other hand, the resistance under light illumination drops to be two orders of magnitude smaller than that in dark. That implies promising and great potentials as an effective photodetector. After analyzing electron transport behaviors of our CH3NH3PbI3 perovskite devices, we confirm the best fitting and explanation of the data by using the theory of Mott’s three-dimensional variable range hopping by which the disorder parameter T_0 is evaluated. The hopping energy of 97 and 220 meV at 100 and 300 K, respectively, are evaluated for our CH3NH3PbI3 perovskites.

APA, Harvard, Vancouver, ISO, and other styles

11

Kuan-TeWu and 吳冠德. "Studies of CH3NH3PbI3 microwires and its application on photodetectors." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/s3782d.

Full text

Abstract:

碩士
國立成功大學
光電科學與工程學系
106
In this study, we investigated the structural and electrical properties of CH3NH3PbI3 microwires prepared by fluid-guided anti-solvent vapor-assisted crystallization; their application in photosensors was also evaluated. The CH3NH3PbI3 microwires were characterized by atomic force microscopy (AFM), scanning electron microscopy, and conductive AFM. CH3NH3PbI3 self-assembled into microwires with directional crystallization, and a single microwire showed memristor-like behavior under light illumination. The electrical properties of CH3NH3PbI3 microwire-based photoconductors were then investigated under laser illumination with various wavelengths. Under blue light illumination, the photoconductors exhibited a photo-responsivity of 15 mA/W; under red and green light illumination, however, a photo-responsivity of only 2 mA/W was obtained. Finally, we studied the photoresponse properties of CH3NH3PbI3 microwire/N,N’-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13) composite-based thin-film transistors (TFTs). A top layer of PTCDI-C13 was thermally deposited onto the CH3NH3PbI3 microwires to form the active layer of TFTs, and results showed that the composite-based TFTs could distinguish different colors of light.

APA, Harvard, Vancouver, ISO, and other styles

12

Zong-YuWu and 吳宗諭. "Photoluminescence Properties of Microstructural CH3NH3PbI3 Perovskite Prepared by Thermal Evaporation." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/c7g4fd.

Full text

Abstract:

碩士
國立成功大學
光電科學與工程學系
104
We report the optical characterizations of perovskite (CH3NH3PbI3) thin films prepared by vapor deposition method. By SEM, we could observe the difference of crystal size and shape between PbI2 and CH3NH3PbI3 prepared by vapor deposition method. The absorbance and transition spectra were investigated to confirm the optical difference between PbI2 and CH3NH3PbI3. Photoluminescence peak of the perovskite films at 780 nm excited via 532 nm CW laser at room temperature was observed, and we confirm the bandgap is around 1.58 eV at room temperature through experiments stated above and temperature-dependent PL measurement. We also found that high photoluminescence stability of perovskite films prepared by vapor deposition at high relative humidity. Last, we observed emission peak located at about 780 nm, and we change the depths of the films which 532 nm CW laser focuses on to observe PL spectra. We found the appearance of two peaks. Through XRD patterns, we could infer the origins of this feature. All measurements except temperature-dependent PL spectra are processed at room temperature and 50% relative humidity. This humidity is much higher than other foreign studies. Perovskite material has high sensitivity to water molecules, so people would prevent perovskite samples from water or high humidity. Thus, our sample is very strong.

APA, Harvard, Vancouver, ISO, and other styles

13

Sung, Shih-Chieh, and 宋仕傑. "Structural and Photo-Physical properties of CH3NH3PbI3 Perovskite Single Crystals." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/71362289463015670529.

Full text

Abstract:

碩士
國立交通大學
應用化學系碩博士班
105
Organo-lead trihalide hybrid perovskites (MAPbX3 ; MA= CH3NH3+, X=Cl-, Br- or I-) have emerged as promising new materials for solar cells. Although efficiencies of perovskite solar cells have achieved exceeding 20%, there are many questions remained to be answered, such as the crystal chemistry of these materials, the mechanism of exciton separation, and the nature of charge transfer. Therefore, research in perovskite intrinsic properties are very important. In particular, solution-prepared MAPbX3 single crystals show long carrier diffusion lengths and low trap–state densities compared to photovoltaic quality silicon. Large MAPbX3 single crystals have been successfully synthesized via different methods over the past few years. In this work, we study the structral and photo-physical characteristics of CH3NH3PbI3 perovskite single crystals with a size of nearly 1 cm3 prepared by using inverse temperature crystallization method. Temperature dependent powder X-ray diffraction reveals phase transition from tetragonal to cubic phase at 320 K and from tetragonal to orthorhombic phase at 90 K, respectively. Measurements of temperature dependent photoluminescence from 360 K to 11 K and cathodoluminescence clearly indicated that the observed luminescence peaks from the MAPbI3 single crystals are not resulted from the surface states, defects or the excitonic recombination. We speculate that the observed PL peak above the absorption bandedge is originated from the band filling effect due to carriers accumulate near the bandgap.

APA, Harvard, Vancouver, ISO, and other styles

14

Jhong-CiaoKe and 柯中喬. "Research on the Properties of Organic and CH3NH3PbI3 Perovskite Solar Cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/6wupz6.

Full text

Abstract:

博士
國立成功大學
微電子工程研究所
104
In this dissertation, the influence of different factors on the performance of organic solar cells (OSCs) and CH3NH3PbI3 perovskite solar cells (PSCs) is investigated in detail. The OSCs are studied and discussed in Chapter 3, and the PSCs are investigated and discussed in Chapter 4. Section 1 in Chapter 3 is focused on the energy states in a cathode buffer layer induced by metal cathode deposition. The absorption spectra show the existence of energy states in the cathode buffer layer, and the energy level of states can be estimated in a quantitative manner. Section 2 in Chapter 3 presents the research on small-molecule OSCs based on boron subphthalocyanine chloride (SubPc) and C60. This research is conducted by varying the SubPc layer thickness from 3 nm to 21 nm. Section 3 in Chapter 3 presents the effect of inserting a molybdenum oxide (MoO3) anode buffer layer into OSCs based on various electron donor materials. Results show a great enhancement of the open-circuit voltage in the device. This enhancement originates from the work function improvement of indium tin oxide (ITO) by covering the MoO3 layer. However, the function of MoO3 is not evident in the device that uses copper phthalocyanine (CuPc) as the donor material. The interaction between MoO3 and CuPc is detected using UV–visible absorption and X-ray photoelectron spectroscopy. The electron transfer between MoO3 and CuPc causes the formation of an interface state at the MoO3/CuPc interface, resulting in Fermi-level pinning at the interface. Consequently, inserting a MoO3 anode buffer layer cannot improve the efficiency of the CuPc/C60 heterojunction device. In Section 4 of Chapter 3, the effect of different electrodes on OSC performance is studied. Various sheet resistances of ITO are used as anodes to determine which resistance is suitable for OSC application. In cathodes, the commonly used for OSCs are Al and Ag. The efficiency of the device based on CuPc and C60 increased from 0.71% to 0.86% when Ag was substituted for Al as a cathode, whereas the efficiency of the device based on SubPc and C60 increased from 2.61% to 2.96%. The performance enhancement was mainly ascribed to the current density improvement, which resulted from the difference in optical characteristics between Al and Ag. In Section 5 of Chapter 3, the effect of OSCs is investigated using different power O2 plasma treatments on ITO substrate. The power of O2 plasma treatment on the ITO substrate varied from 20 W to 80 W. Therefore, the power of O2 plasma treatment on the ITO substrate for OSC application should be controlled below 40 W to avoid affecting the electricity of the ITO film. In Section 1 of Chapter 4, the effect of PSCs fabricated using various solvents is studied. The device was composed of an ITO/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) / CH3NH3PbI3 (fabricated using various solvents) / C60/bathocuproine (BCP) / Ag structure. The solvents are dimethylformamide (DMF), γ-butyrolactone (GBL), dimethyl sulfoxide (DMSO), a mixture of DMSO and DMF (DMSO:DMF; 1:1 v/v), and a mixture of DMSO and GBL (DMSO:GBL; 1:1 v/v). As a result, a power conversion efficiency (PCE) of 9.77% was obtained using the mixed solvent of DMSO:GBL because of smooth surface roughness, uniform film coverage on the substrate, and high crystallization of perovskite structure. Finally, the mixed solvent of DMSO:DMF:GBL (5:2:3 v/v/v), which combined the advantage of each solvent at an appropriate ratio, was used to fabricate the device, thereby leading to the further improvement of the PCE of PSCs to 10.84%. In Section 2 of Chapter 4, the effects of PSCs using different temperature annealing treatments and various materials as acceptors are studied. The device was composed of an ITO/PEDOT:PSS/CH3NH3PbI3 (different temperature annealing treatments) / acceptor materials/ BCP / Ag structure. The thermal annealing treatments of CH3NH3PbI3 layers were conducted from 60 °C to 120 °C. Results show that the temperature of the annealing treatment has significant influences on the PCE of the device. The acceptor materials used in the device were C60, C70, and 3,4,9,10-perylenetetracarboxylic bisbenzimidazole. This finding shows that the mechanism of PSCs is similar to the concept of OSCs, in which the donor/acceptor interface dissociates the electron–hole pair via the energy level difference to produce the photovoltaic effect. Therefore, an efficiency of 11.58% was obtained in CH3NH3PbI3 PSC.

APA, Harvard, Vancouver, ISO, and other styles

15

Chang, Shuang-Yuan, and 張瀧元. "Fabrication and Application of CH3NH3PbI3-Modified P3HT:ICBA High Voltage Solar Cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/66789467571192387680.

Full text

Abstract:

碩士
國立臺灣大學
材料科學與工程學研究所
104
P3HT:ICBA polymer solar cell system has been extensively investigated in recent year due to its high efficiency, high stability and the ease of synthesis. On the other hand, organic-inorganic hybrid perovskites have the ambipolar property, which can produce voltage by themselves under light irradiation. In this work, we combine the P3HT:ICBA and perovskite system by introducing perovskite as high voltage driver into P3HT:ICBA solar cells to enhance their voltage performance. In order to reduce the energy consumption and increase more extensive choices of materials in active layers, we develop the whole non-annealing fabrication process, the interconnecting layers, perovskite layer and hole transport layer of perovskite are process without annealing. Compared with the standard P3HT:ICBA solar cell, the CH3NH3PbI3-modified P3HT:ICBA solar cell with 3nm MoO3/ZnO interconnecting layers show significant enhancement in open circuit voltage (Voc) and power conversion efficiency (PCE), increase from 0.86V to 1.60V and 3.34% to 4.35%, respectively. Under more than 210 days (5,040 hours) storage, compared 210th with 1st day measuring Voc results of the CH3NH3PbI3-modified P3HT:ICBA solar cell with 3nm MoO3/ZnO decays within 3%. Besides, the Voc of the modified solar cell can still maintain above 1.55V, which is valuable record because normally the commercial appliances need to be driven above 1.50V. To simplify the manufacturing process, we also try to remove the electron and hole transport layers of perovskite. Compared with the standard P3HT:ICBA solar cell, the CH3NH3PbI3-modified P3HT:ICBA solar cell with 11nm MoO3 interconnecting layer exhibits great improvement in Voc and PCE, raise from 0.82V to 1.28V and 3.03% to 3.40%, respectively. It proves that single perovskite layer can be the high voltage driver of P3HT:ICBA solar cells. Finally, for the practical application, we successfully prove that our modified solar cells can provide enough voltage output to drive commercial appliances no matter under one sun or dim light irradiation.

APA, Harvard, Vancouver, ISO, and other styles

16

Kuo, Liang-Cheng, and 郭量承. "Nanosecond time-resolved near-infrared spectroscopic study of CH3NH3PbI3 perovskite thin films." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/t83rmk.

Full text

Abstract:

碩士
國立交通大學
應用化學系碩博士班
104
Organic-inorganic lead halide perovskite CH3NH3PbI3 has emerged as a promising light harvesting material for the industry of solar energy. There are many advantages of the perovskite to be utilized, such as efficient energy conversion properties and low manufacturing cost. Photophysical characteristics of the perovskite such as a high charge carrier mobility and a long diffusion length of photoinduced free charge carriers have also attracted great interest among chemists and materials scientists. Although the kinetic behaviors of charge separation in the ultrafast time regime have been a focus of intensive research, little has been studied on much slower dynamics such as recombination of the generated charge carriers. In the present study, high-sensitivity nanosecond time-resolved near-infrared (TRNIR) spectroscopy was used to elucidate the mechanisms of the recombination dynamics of the charge carriers (electrons and holes) in CH3NH3PbI3 perovskite thin films. A series of transient NIR spectra (12000–3800 cm−1) of the perovskite films with different concentrations of CH3NH3PbI3 were measured after photoexcitation at 532 nm. Results revealed two types of radiative decays in the NIR region. One transient appears above 10000 cm−1 and decays almost instantaneously with a time constant comparable to the apparatus response of ~20 ns. The other transient has a very broad feature that covers the entire NIR window of our observation and seems to exhibit a slower decay together with a rapid decay similar to the higher-wavenumber transient. The origin of these transient species is discussed in terms of trap states in the perovskite thin films. Furthermore, the effects on the TRNIR spectra of the presence of cyclohexane on the perovskite films are also examined. It was found that the presence of a solvent could significantly affect the NIR optical properties of the charge carriers. The present study demonstrates that TRNIR spectroscopy provides new insight into the carrier dynamics in the perovskite.

APA, Harvard, Vancouver, ISO, and other styles

17

BO-SYUNCIOU and 邱柏勳. "Origin of the Thermal Instability in CH3NH3PbI3 Thin Films Deposited on ZnO." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/gnj372.

Full text

Abstract:

碩士
國立成功大學
物理學系
104
In this research, we study the instability in perovskite (CH3NH3PbI3) thin films deposited on ZnO. We manufactured ZnO films by using ion beam sputter (IBS) system to sputter ZnO target with argon flux and deposited perovskite film on the top of ZnO by solvent engineering method. We analyzed the characteristics of as-formed perovskite on the ZnO substrate by GIXRD, SEM, AES, UV-VIS…etc. The analysis of XRD and UV-VIS show that the stability in perovskite has relation to the baking temperature of perovskite and the Zn/O2 ratio of the ZnO substrate. The results indicate that the instability of perovskite increases as the Zn content increases. Furthermore, we deposited perovskite film on pure Zn film for comparison. The GIXRD shows that the reaction takes place between Zn and PbI2 with a chemical reaction as follows: Zn+PbI2→ZnI2+Pb It prove that the stability of perovskite is dominated by the Zn content.

APA, Harvard, Vancouver, ISO, and other styles

18

Wan-LinTsai and 蔡萬霖. "Effect of incorporating potassium iodide on CH3NH3PbI3 resistive random access memory properties." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/x4n69q.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Lin, Wei-Jen, and 林韋任. "A First-Principle Study of the Thermal Degradation Mechanisms of CH3NH3PbI3 Perovskite." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/94s2mz.

Full text

Abstract:

碩士
國立中央大學
化學學系
106
The poor stability of organometallic halide perovskite, especially the CH3NH3PbI3 (MAPbI3), in high temperature environment (up to 85 ºC) is one of the challenge problems retarding for its wide applications. The thermal degradation mechanism of CH3NH3PbI3 perovskite remains unclear. In this study, we employ firstprinciple density functional theory to investigate the energetic and structural mechanisms of the thermal degradation of CH3NH3PbI3 perovskite. We focus on studying the two reaction pathways of iodine with the CH3NH3+: one reaction is the proton abstraction reaction from methylammonium to iodine and the products are hydrogen iodide (HI) and methylamine (CH3NH2). The other reaction is a SN2 substituent reaction using the iodine as the nucleophile to attack the carbon atom of CH3NH3+ to yield the products of iodomethane (CH3I) and ammonia (NH3). The crystal structures of CH3NH3PbI3 perovskite with PbI2-terminated and MAI-terminated surfaces are employed in this study. Our calculations suggest that the SN2 substituent reaction requires lower activation energy than the proton abstraction reaction. Namely, the main products of the thermal detraction of CH3NH3PbI3 perovskite are CH3I, NH3, and PbI2. Our study gives clues to rationally design of the thermally stable organic cations. To verify the overall mechanism, we will scan the 2D energy profiles to make sure that PbI2 generates in our future work.

APA, Harvard, Vancouver, ISO, and other styles

20

MulongYang and 楊牧龍. "Deposition and I-V hysteresis of CH3NH3PbI3 perovskite on planar heterojunctioned solar cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/99136657590306569918.

Full text

Abstract:

碩士
國立成功大學
材料科學及工程學系
103
The alkyl-ammonium metal trihalide perovskites are an exciting new class of solar absorber materials and have exhibited a rapid increase in solar cell efficiencies throughout the past three years to over 20%. Good quality and high orientation perovskite crystalline films were expected to less recombination and faster electron flux. Two common deposition method is utilized to assemble planar heterojunctioned perovskite solar cells, one-step solution method and two-step sequential solution method. Spin-coating is the most common depositing process of perovskite. In this work, we used a novel method to synthesized modified PbI2 film which could be used for intramolecular exchange in two-step method. And discussed the influence of different one-step recipe to perovskite thin film formation. I-V hysteresis was also investigated, finding that hysteresis phenomena fitting theoretical assumption. Intensity modulated photovoltage spectroscopy (IMVS) measurement was introduced into perovskite solar cells for carrier life time calculating. This work preliminarily discussed the impact factor of perovskite thin film deposition, I-V hysteresis and carrier life time.

APA, Harvard, Vancouver, ISO, and other styles

21

Zheng, Hung Tien, and 鄭弘田. "Development of Flow Environmental TEM for In-situ Observing of Synthesis of Perovskite(CH3NH3PbI3)." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/64y3j4.

Full text

Abstract:

碩士
國立清華大學
工程與系統科學系
103
Perovskite solar cells have received considerable attention in recent years as a promising material capable of developing high performance photovoltaic devices. The efficiency of perovskite solar cells has increased to 20.1% from an initial 3.8% within 5 years. However, until now there is no study can directly observe the formation mechanism of Perovskite in nano scope. Therefore, in this research we developed home-made TEM liquid holder and with flow cell chip to study this issue. This research consists of three sections: (1) Observing nano-particle move via liquid injection, that could be initially confirmed the availability of TEM liquid holder. (2) Observing an aqueous solution of hydrogen peroxide catalyzed by Platinum is decomposed to oxygen nano-bubble movement and merging, that could confirm dynamic motion and chemical reaction are allowed in this system. (3) Successfully level up the resolution to atomic scale (Å) via using special way to control the liquid thickness in order to obtain the transformation of lattice structure in real time. Then in situ observing the process of lead iodide (PbI2) and Methyl ammonium iodide(MAI) to form MAPbI3 (CH3NH3PbI3). Our work not only demonstrates the feasibility of home-made TEM liquid holder but also bridge the in-situ TEM technique with the field of novel energy material synthesis so that make contribution to critical scientific issues.

APA, Harvard, Vancouver, ISO, and other styles

22

Cheng-TienChu and 朱正田. "p-Aminobenzoic acid hydrochloride assisted crosslinking of CH3NH3PbI3 in planar-heterojunction perovskite solar cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/ptcyu4.

Full text

Abstract:

碩士
國立成功大學
化學工程學系
104
This research focused on using p-ABACl as a crosslinking additive in the precursor of perovskite. p-ABACl can not only improve the surface morpgology of the perovskite but also strengthen the moisture resistance by forming hydrogen bonding and crosslinking the perovskite grains. In the first part of this research, we synthesized p-ABACl and clarify the composition of the product through NMR and IR. We added p-ABACl into the perovskite precursor and surprisingly found that with p-ABACl as an additive, we could obtain perovskite film simply through one-step fabrication process. With p-ABACl, we could increase the PCE of perovskite solar cells from the average PCE of 0.19% for pristine devices to 10.03% for perovskite with p-ABACl. And their best PCE are 0.32% and 12.39%, respectively. Moreover, in the stability test, the pristine lost almost all of the function after exposing to the air for only one day without any encapsulation. However, the perovskite solar cells lost 50% of their original PCE until exposing to the air for 11 days. In the second part, we focused on finding the reasonable explanations for the results we had gotten in the first sector of this research. Firstly, we turned to NMR and TEM to elucidate the role of p-ABACl in the precursor solution and the distribution in the solid crystal. To define the function of the different part of p-ABACl molecule, we used some molecules with the similar structure as p-ABACl and analyzed through the SEM and perovskite solar cell devices.

APA, Harvard, Vancouver, ISO, and other styles

23

FanessaFirdausi and 傅達司. "Solid-State Solar Cell-Based on CH3NH3PbI3 Perovskite Sensitizer and Mesoporous Anatase TiO2 Beads." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/55155817928241614599.

Full text

Abstract:

碩士
國立成功大學
材料科學及工程學系
102
Mesoporous metal oxide films have been usually adopted for solid-state dye sensitized solar cells (DSC); however, difficulty in pore filling has been an issue in such nanoparticulate films. Beads structure were reported have higher surface area and to be better in electron transport than commercial nanoparticles P25. These characteristics makes anatase TiO2 beads are capable to enhance the dye loading, leading to light absorbance and overall cell efficiency. Mesoporous anatase TiO2 beads were prepared over two steps, including sol-gel and hydrothermal processes. In other hand, the CH3NH3PbI3 perovskite material shows a direct bandgap and wide range of light absorption covering the visible to near-IR spectrum as well as high extinction coefficient, that would be very advantageous as a sensitizer. Here, anatase TiO2 beads were used for the fabrication of solid-state perovskite sensitized solar cell, which then acts as an electron transporting layer. Nanoparticle TiO2 (commercial P25) were also used as a comparison. The perovskite sensitizer then were deposited onto the electron transporting layer, either by sequential or VASP techniques. The crystal structure and the morphology of the resulting beads powders were examined using x-ray diffraction and scanning electron microscope, respectively. The surface area of final beads product were measured using BET analysis. Finally, the device were evaluated using solar cell characterization.

APA, Harvard, Vancouver, ISO, and other styles

24

Yang, Tsu Hao, and 楊祖豪. "In situ observation for growth of PbI2 and CH3NH3PbI3 nanocrystals in liquid cell TEM." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/00595600326501376672.

Full text

Abstract:

碩士
國立清華大學
工程與系統科學系
104
There has been an increasing interest in renewable energy issue and perovskite type solar cell because of the following advantages of perovskite solar cell: high absorption coefficient, flexibility, low cost, and the rapid growth of efficiency that has been improved from 3.8% up to 20% in only six years (2009-2014). However, there are still lack of the direct evidences for the synthesis and growth of CH3NH3PbI3 peovskite nanocrystals in TEM. Hence, in order to help fill this gap in our knowledge, this study investigated the synthesis and growth of CH3NH3PbI3 peovskite nanocrystals by in situ liquid TEM. In this study, we show the new design of spacer in wet cell chip, which creates a larger flow channel to improve flowing system, and in situ observation for PbI2 nanocrystals growing by in situ liquid TEM. Furthermore, according to LSW theory, the growth of PbI2 is approaching to reaction limit mechanism. Finally, we demonstrate in situ observation for synthesis and growth of CH3NH3PbI3 perovskite nanocrystals, and also discuss the possible mechanism.

APA, Harvard, Vancouver, ISO, and other styles

25

HUNG, CHIA-TSUNG, and 洪嘉聰. "Nanocrystal Film by Chemical Bath Deposition of Colloidal CH3NH3PbI3 Perovskite for Planar Heterojunction Solar Cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/syd8gq.

Full text

Abstract:

碩士
國立臺南大學
綠色能源學科技學系碩士在職專班
106
The conversion efficiency of perovskite solar cells has rapidly reached to 22.1% within a decade. But the perovskite materials are unstable in the atmosphere, most of the researches are running in controlled inert gas environment. In this study, the CH3NH3PbI3 organic-inorganic hybrid perovskite nanocrystal film is fabricated by chemical bath deposition in the open atmospheric environment. The synthesis of colloidal perovskite nanocrystals and the chemical bath deposition are both without using any polar solvents, by coordinated with capping ligands, the nanocrystals aggregated and deposited then self-assembled to form the CH3NH3PbI3 perovskite nanocrystal films. The average grain size of the perovskite nanocrystal film with PbI2 seed is about 25 nm, and with 10.3% of efficiency. The mechanism proposed in this study is different from the previous hot injection reaction of the colloidal inorganic perovskite nanocrystals, by the lower formation energy of CH3NH3PbI3, the nanocrystal is able to self-assemble in room temperature through the ionic metathesis reaction, and coordinated with the capping ligands. By removing the ligands from the deposition, the nanocrystals are then self-assembled into a smooth and continue nanocrystal films.

APA, Harvard, Vancouver, ISO, and other styles

26

PoChang and 張博. "Using in-situ photoluminescence measurement to investigate photophysics of organometallic halide CH3NH3PbI3 under different environmental conditions." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ck8jfm.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Kuo, Kuo-Sheng, and 郭國盛. "Study on the Stability of Methylaamine Iodide Lead (CH3NH3PbI3) Perovskite by Photoluminescence Spectroscopy and Electrical Measurement." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/bs9qp8.

Full text

Abstract:

碩士
中原大學
物理研究所
106
The organic-inorganic hybrid perovskite has very poor stability in the environment; it easily reacts with elements in the environment to degrade. To improve the stability of the methotrexate lead perovskite, we tried to using a cover layer to keep the perovskite sample from the harmful element in the environment. We use SiO2 and LiF as cover layer, because this two materials won’t affect the electrical measurement, and tens of nanometers thick of this two materials have good light transmittance without affecting the photoluminescence measurement. Then we used photoluminescence measurement and electrical measurement to verify the change of methyl iodide lead perovskite with time and with the number of measurements. From the experimental results, we found that both protective layer materials have the effect of insulating the gas in the atmosphere to improve the stability of the sample. However, in the production of the cover layer of SiO2, it’s easy to diffuse oxygen into the crystal lattice of the methyl iodide-lead perovskite, so that the sample after the measurement is rapidly degraded. The lithium fluoride protective layer sample can effectively play a role in greatly improving the stability of the MAPbI3 perovskite.

APA, Harvard, Vancouver, ISO, and other styles

28

Che-LiChung and 仲哲立. "Direct Conversion of CH3NH3PbI3 by Low-pressure Chemical Vapor Deposition with Electrodeposition PbO2 for Perovskite Solar Cell." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/dwep97.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Yung-FuChen and 陳永富. "Study on Lead Sulfide buffer layer induced the preferential growth of CH3NH3PbI3 films and its resistive memory properties." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/yt6msv.

Full text

Abstract:

碩士
國立成功大學
電機工程學系
105
In this study, PbS buffer layer with (100) preferred orientation was deposited via chemical bath deposition (CBD) process. It is expected to control the orientation of the CH3NH3PbI3 thin film by incorporating the PbS buffer layer. The PbS buffer layer induced the preferential growth of CH3NH3PbI3 perovskite films (PbS-seeding process) involves three-step processes. a. PbS deposition: The PbS buffer layer was deposited via CBD method. b. PbI2 conversion: Iodization treatment of PbS to form PbI2. c. CH3NH3PbI3 conversion: Formation of CH3NH3PbI3 by simultaneous annealing and exposure to MAI vapor at low pressure. As compared to the spin-coating derived CH3NH3PbI3 thin film, the PbS-seeded growth of CH3NH3PbI3 thin film exhibited a larger grain structure, leading to a (110)-textured structure (Figure 1(a)). For comparison, the resistive random access memories (RRAM) were constructured by these two kinds of CH3NH3PbI3 film (PbS-seeding process and spin-coating process). Figure 1(b) shows a typical I-V characteristic of RRAM with the CH3NH3PbI3 thin film prepared by the PbS-seeding process.

APA, Harvard, Vancouver, ISO, and other styles

30

LIU, QI-HAN, and 劉其翰. "One-step solution process for preparing high-quality CH3NH3PbI3 perovskite: Effect of processing additive and hole transport layer." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/jk54d8.

Full text

Abstract:

碩士
國立臺北科技大學
分子科學與工程系有機高分子碩士班
107
The power conversion efficiency (PCE) of inorganic-organic perovskite solar cells (PSCs) has been improved rapidly over the last several years and reached a remarkable value of 24%. However, the current preparation route of photoactive perovskite films is too complicate to be used to develop a continuous process for making large-scale devices. In the first part of this study, I found that the nature of hole transport layer plays an important role affecting the growth behavior of perovskite. As poly(3-hexylthiophene) derived polyelectrolytes, (P3HT-COOH), replaces PEDOT:PSS as the hole transport layer, a processing additive, such as DMSO, is no longer needed to produce uniform and high-quality perovskite films through one-step solution process. The so-called anti-solvent process is still the most effective route to produce a smooth film of CH3NH3PbI3 crystals through a simple one-step procedure. During the spinning drying, the perovskite solution must be washed with an anti-solvent at a specified delay time that significantly obstructs its practical use in a low-cost, large-area and continuous process. In the second part of this work, I demonstrated that the replacement of DMSO with tetrahydrothiophene 1,1-dioxide (sulfolane) as the processing additive can largely broaden the window of delay time from 6 – 15 to 6 – 90 seconds without sacrificing the photovoltaic performance of PSCs. Different from the formation of an intermediate phase in the conventional route, the XRD diffraction patterns showed the perovskite crystals were produced immediately after the anti-solvent washing step. Moreover, the FTIR spectrum indicated the S=O moieties in sulfone can form hydrogen bonding with methylammonium ions. This finding suggests that the sulfolane may act as a retardant which interrupts the physical contact of MA+ and PbI3- ions and prevents the quick growth of perovskite crystals into a porous structure. I further confirmed that this new approach enables the use of dip-washing instead of drip-washing of anti-solvent to fabricate PSCs with a PCE over 16%.

APA, Harvard, Vancouver, ISO, and other styles

31

Berhe, Taame Abraha, and Taame Abraha Berhe. "Room Temperature Synthesis, Mechanism and Stability Analysis of CH3NH3PbI3 and the Development of Transition metal (I) cation based New Inorganic Perovskites." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/34368309675496013717.

Full text

Abstract:

博士
國立臺灣科技大學
應用科技研究所
105
The existing issues in this area of organometallic halide perovskite solar cells (Omh-PSC) were first reviewed in this work. Omh-PSCs have evolved in an exponential manner in the two key areas of efficiency and stability. The power conversion efficiency (PCE) reached 23.6% in late 2016. The key disquiet was stability, which has been limiting practical applications, but now is in a promising state of the art, measured in thousands of hours. These improvements have been achieved with the application of different materials, interfaces and device architecture optimizations, especially after the investigation of hole conductor free mesoporous device, incorporating carbon electrodes, which promise stable, low cost and easy device fabrication methods. However, this work is still far from complete. A comprehensive understanding of these issues is required to achieve stability breakthroughs and practical outdoor applications for Omh-PSCs. The causes of failure and associated mechanisms of device degradation followed by the origins of degradation, approaches to improve stability, and methods and protocols are discussed in detail. Therefore, this work helps us conduct the following work on (1) material facile and scalable synthesis methods and characterization of its structure-property relationships; (2) understanding of the PL lifetime as a function of photoexcited state dynamics using laser light irradiation and thermal treatment as controlling parameters for the study. And (3) development of new perovskites material using computational methods and suggesting some promising fully inorganic perovskites materials with metal(I) cation replacing methylammonium cation.

APA, Harvard, Vancouver, ISO, and other styles

32

Chang, Chih-Wen, and 張志文. "Two Step Sequential Deposition of CH3NH3PbI3-xBrx-based Perovskite Solar Cell Fabricated from Porous PbX2 Obtained with Mixture Organic Solvent Treatment." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/penv99.

Full text

Abstract:

碩士
國立清華大學
化學工程學系所
105
Organo-lead halide perovskite solar cells (PSC) are one of the most promising photovoltaic devices because of their extraordinary power conversion efficiencies. It is known that the performances of perovskite solar cells depend heavily on the uniformity, surface coverage, and thickness of the perovskite active layer. Typically, solution processing of perovskite films in PSCs is carried out using one-step or two-step method. In the one-step method, the perovskite films are directly deposited onto mesoporous metal oxide using a mixture of PbX2 (X = Cl, Br, I) and CH3NH3X in a polar solvent. However, it is difficult to control the morphology of the resulting perovskite layer in the one-step method, leading to a wide fluctuation in photovoltaic performances. In the two-step method, PbI2 is first deposited onto the mesoporous TiO2 scaffold layer. The CH3NH3I (MAI) solution is then introduced to the PbI2 layer to react and form the CH3NH3PbI3 layer. It is much easier to control the morphology of the perovskite layer with the two-step method than with the one-step method. But the main challenge for the two-step method is the volume expansion issue during the formation of the perovskite, leading to incomplete conversion of PbI2, which is detrimental to the photovoltaic performance. In this work, we choose CH3NH3PbI3-xBrx-based perovskites as the active layer and further modify the traditional two-step method in order to address the volume expansion issue of the PbI2 precursor film. Here we develop a solvent soaking method to produce porous PbX2 layers. We use binary mixture organic solvent, diethyl ether and toluene (ether/toluene) to produce porous PbX2, enabling easier MAI solution infiltration into the entire pore space accessing rapidly the interior of the mesoporous PbX2 layer and thus more complete conversion of PbX2 to perovskite. From XRD, UV-Vis, PL, and TR-PL analyses, it is proved that the perovskite films derived from the ether/toluene treatment have better crystallinity, fewer defect states, and longer lifetime than the perovskite films derived from the traditional two-step method. As a result, the average power conversion efficiency was enhanced from 10.03% for the control device up to 12.32% for the ether/toluene treated device under AM 1.5G solar illumination of 100 mW cm-2. From the IPCE data, we found that the highest efficiency was boosted from 65% to 75% in the visible light region as a result of the high quality perovskite layer derived from the ether/toluene treated PbX2 films. Furthermore, by optimizing the processing condition, we found that the increase in the PbX2 annealing temperature from 70℃ up to 100℃ created the optimal fraction of voids in the PbX2 films, leading to larger grains and more dense perovskite capping layer, which can reduce the trap states in the perovskite films and enhance the light harvesting efficiency. The power conversion efficiency of the champion cell is up to 13.16%.

APA, Harvard, Vancouver, ISO, and other styles

33

Lin, Chang-Rong, and 林昶嶸. "The Study of Efficiency Enhancement for White Light Organic Light-Emitting Diodes and CH3NH3PbI3 Perovskite Solar Cells via Nano-Patterned Substrate." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/e7udb6.

Full text

Abstract:

博士
國立中央大學
能源工程研究所
107
In this study, we have synthesis the SiO2 sphere with variable diameters by tuning the recipes of sol-gel method, and successfully improve the efficiency via incorporating the spheres into an organic light-emitting diode (OLED) and an organic-inorganic halide perovskite solar cell (PSC). In terms of OLED, the output power enhancement of the white light OLED was demonstrated on a patterned indium tin oxide substrate (PIS) prepared via sphere lithography technique which consists of self-assembled monolayer SiO2 spheres and dry etching process. Herein, three different periods of PIS OLEDs (PIS-300 OLED, PIS-500 OLED and PIS-1000 OLED) were fabricated by selecting the diameter of deposited SiO2 spheres. Through simulation results and a series of experimental analyses, PIS OLEDs present better device performance than a Planar OLED (Control Sample), and the device performance was inversely proportional to the structural period of the PIS OLED. Compared with the planar OLED, the operating voltage of the PIS-300 OLED with smallest structural period of 300 nm was reduced 36% at an injection current density of 20 mA/cm2. Consequently, the luminous efficiency and external quantum efficiency of PIS-300 OLED can statically enhanced 228% and 58% at the luminance of 5,000 cd/m2. In terms of PSC, a CH3NH3PbI3-based perovskite solar cell (PSC) with high power conversion efficiency (PCE) has achieved by incorporating a nano-patterned fluorine-doped tin oxide (FTO) substrate (NPFS). This NPFS-PSC was prepared with different structural depths (100 nm, 150 nm, and 200 nm) using both self-assembly and sphere lithography techniques. As determine through the optical and electrical analysis of different PSC devices, the NPFS-PSCs not only display the enhanced light absorption (due to the two-dimensional diffraction grating) but also improve the electron collection efficiency by increasing the FTO/electron transport layer (ETL) and ETL/perovskite effective interface. Compared to a planar PSC (Control Sample), the photocurrent density of the 200-nm-etched NPFS-PSC is enhanced from 19.27 mA/cm2 to 23.81 mA/cm2 leading to an increase in the power conversion efficiency from 14.21% to 17.85%. These results indicate that introducing the NPFS into the CH3NH3PbI3-based PSC can improve both light harvesting and electron extraction efficiency and, therefore, represents a novel, promising, high-performance photovoltaic device.

APA, Harvard, Vancouver, ISO, and other styles

34

Sharada, G. "Structure, Dynamics and Optical Properties of Organic-Inorganic Hybrid Perovskites." Thesis, 2017. http://etd.iisc.ac.in/handle/2005/4129.

Full text

Abstract:

Organic-inorganic hybrid perovskites have emerged as promising photovoltaic materials in the last few years, with the possibility of easy, solution synthesis. In this thesis, we have investigated some intrinsic material properties of the hybrid lead halide perovskites in an attempt to understand factors responsible for the excellent photovoltaic behaviour. The presence of the (CH3NH3)+ or methylammonium (MA) ion with a permanent dipole moment in CH3NH3PbI3 gives rise to the possibility of ferroelectricity. In view of the continued controversy concerning the ferroelectric/non-ferroelectric nature of CH3NH3PbI3, we have addressed the more basic question of whether it is polar or not. We have measured the Second Harmonic Generation (SHG) efficiency, which is a sensitive probe to the presence of centre of inversion in the system and show that SHG efficiency of CH3NH3PbI3, if non-zero, is below the detection limit, strongly indicative of a nonpolar structure; consistent with P-E loop and single crystal XRD measurements. This nonpolar structure is a time-averaged description of the MA dipoles, consistent with many different dynamic behaviours, such as MA units rotating freely or in a correlated manner or frozen randomly. A comparison of temperature dependent dielectric constants of MAPbX3 and CsPbBr3 (without dipolar units) suggests that the MA+ dipoles are rotating freely with time scales much faster than μs. Ab initio molecular dynamics simulations show that these dipoles are randomly oriented with no net dipole moment when averaged over even a few unit cells, with a rotational time scale of ~ 7 ps at 300 K for these dipoles. Further, using pump-probe SHG efficiency measurements in MAPbX3 we have ruled out the possibility of a transient ferroelectric state in presence of photoexcitation. Further, we have carried out detailed investigation of dielectric properties of a larger class of hybrid lead halide perovskites, specifically the formamidinium lead halides (FAPbX3). Although the behaviour of dielectric constants of FAPbCl3 and FAPbBr3 in the low temperature resemble that of the MAPbX3 system, the absence of its strong temperature dependence in contrast to MAPbX3 lead us to conclude that the formamidinium (FA) dipoles are frozen in a glassy state. This is supported by the temperature dependent single crystal XRD results, which reveal disordered FA ions in the room temperature as well as at 100 K. Exciton binding energy is an important parameter in a photovoltaic material since it determines whether the mechanism is dominated by free charge carriers or excitons at room temperature. The exciton binding energy reported for MAPbI3 in the literature varies over a wide range of values. From careful experiments to measure temperature dependent PL spectra of MAPbI3 and MAPbBr3 we have estimated the exciton binding energy. PL intensity of MAPbBr3 films is observed to be sensitive to vacuum, environmental conditions and illumination. Since the penetration depth of the excitation wavelength, 405 nm, is very small in the sample, most part of the PL intensity observed can be considered to be from the near-surface region of the sample. We propose that defects are created at the surface of MAPbBr3 by the evaporative loss of MABr due to dynamic pumping. Considering all these factors, we have obtained the binding energy of MAPbBr3 film to be 79 meV, which corresponds to the intrinsic nature of the surface of MAPbBr3 film in vacuum.

APA, Harvard, Vancouver, ISO, and other styles

35

LI, MU-TIEN, and 李慕天. "The study of developing ZnO/CH3NH3PbBr3 Nanocapsule." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ce5js9.

Full text

Abstract:

碩士
逢甲大學
光電科學與工程學系
107
The purpose of this study was developing a new type of nanoluminescent structure，combine with organic material (Perovskite) and inorganic material (Zinc oxide) to achieve organic/inorganic composite material to apply in new type of light source. The ZnO nanorods were grow by hydrothermal. The morphology of nanorods was changed from nanorods to nanotubes via chemical aqueous etching process with well-controlled reaction time. The methylammonium lead bromide perovskite (MAPbBr3) were synthesis by simple two step and fill into ZnO nanotubes then coat ZnO layer by sputter, the nanocapsule structure was obtained. The optical properties was researched. In the result, MAPbBr¬3 have been successfully filled in ZnO nanotubes and sealed. Using 405 nm light source to excite that 540 nm green light can be measured. The 540 nm wavelength of light was from free carrier complex of perovskite material. It also proved Perovskite MAPbBr3 could light effective inside the ZnO nanotubes. The organic/inorganic nanocapsule are able to apply in nanolaser or nano-light sorce.

APA, Harvard, Vancouver, ISO, and other styles

36

(6639662), Kyle Reiter. "Reduced Degradation of CH₃NH₃PbI₃ Solar Cells by Graphene Encapsulation." Thesis, 2019.

Find full text

Abstract:

Organic-inorganic halide perovskite solar cells have increased efficiencies substantially (from 3% to > 22%), within a few years. However, these solar cells degrade very rapidly due to humidity and no longer are capable of converting photons into electrons. Methylammonium Lead Triiodide (CH3NH3PbI3 or MAPbI3) is the most common type of halide perovskite solar cell and is the crystal studied in this thesis. Graphene is an effective encapsulation method of MAPbI3 perovskite to reduce degradation, while also being advantageous because of its excellent optical and conductive properties. Using a PMMA transfer method graphene was chemical vapor depostion (CVD) grown graphene was transferred onto MAPbI3 and reduced the MAPbI3 degradation rate by over 400%. The PMMA transfer method in this study is scalable for roll-to- roll manufacturing with fewer cracks, impurites, and folds improving upon dry transfer methods. To characterize degradation a fluorescent microscope was used to capture photoluminescence data at initial creation of the samples up to 528 hours of 80% humidity exposure. Atomic force microscopy was used to characterize topographical changes during degradation. The study proves that CVD graphene is an effective encapsulation method for reducing degradation of MAPbI3 due to humidity and retained 95.3% of its initial PL intensity after 384 hours of 80% humidity exposure. Furthermore, after 216 hours of 80% humidity exposure CVD graphene encapsulated MAPbI3 retained 80.2% of its initial number of peaks, and only saw a 35.1% increase in surface height. Comparatively, pristine MAPbI3 only retained 16% of its initial number of peaks and saw a 159% increase in surface height.

APA, Harvard, Vancouver, ISO, and other styles

37

Wang, Kai-Hung, and 王凱弘. "Structural and Photo-physical properties of CH3NH3PbBr3 Perovskite single crystals." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/95a62c.

Full text

Abstract:

碩士
國立交通大學
應用化學系分子科學碩博士班
105
In this work, we have evaluated the structural, photo-physical characteristics of MAPbBr3 single crystals using temperature dependent XRD, absorption, time-resolved/steady-state photoluminescence, and Raman spectroscopy techniques The perovskite single crystals are synthesized by using inverse temperature crystallization method. In contrast to previous research reports on perovskite materials, we study changes in optical properties accompanied with the phase changes in crystal lattice structures expanded throughout a wide temperature range from 295 K to 1.5 K. Temperature dependent X-ray diffraction studies reveal phase transitions from cubic to tetragonal and from tetragonal to orthorhombic phase at 220 K and 145 K, respectively. Furthermore, measurements of temperature dependent photoluminescence clearly indicate that the observed luminescence peaks from 4.5 K to 295 K can be attributed to the band gap of MAPbX3 single crystals. Interestingly, at a temperature lower than 80 K, the multiple emission peaks are observed and they are attributed to co-exist of two different crystallographic phases, which is also evident in the temperature dependent XRD measurements. The luminescence peaks are asymmetric in line shape with a weak and broad shoulder near the absorption edge. It is resulted from the presence of the Br atoms vacancy on the surface of crystals. Further to demonstrate, we also investigate the time-resolved photoluminescence on the MAPbX3 single crystals. Wherein, the obtained different luminescence lifetimes in vacuum and in air could be due to the desorption/adsorption of oxygen molecules at the crystal surface. Thereafter, Raman spectroscopic measurements are carried out and compared between MAPbBr3 and MAPbCl3 single crystals. Energy shifts in the Raman spectra are observed when the Br atoms were replaced with the Cl atoms. This is due to the strong interplay between the halide ions with the specifically aligned MA groups, particularly in the vibration modes related to the N atoms. It is also well confirmed that there is no spectral signals related to PbBr2 vibronic stretching. Therefore, there should be no PbBr2 residual remained in the crystals. Lastly, we also investigate the ferromagnetic property of the MAPbBr3 crystals by place the crystal at low temperature and in high magnetic field. The photoluminescence spectra are unaffected by the applied magnetic field up to 5 T.

APA, Harvard, Vancouver, ISO, and other styles

38

Hsu, Hao-Ping, and 徐浩平. "Structural, Photo-physical and Electrical Properties of CH3NH3PbCl3 Perovskite Single Crystals." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/d4y236.

Full text

Abstract:

碩士
國立交通大學
應用化學系碩博士班
107
Research on intrinsic property of perovskite single crystals is becoming essential for future device refinements. In this thesis, we focus on the structural and photo-physical properties of MAPbCl3 single crystals using temperature-dependent steady-state photoluminescence, absorption, X-ray diffraction spectroscopy, and Raman spectroscopy. The carrier concentrations, mobility and photoconductivity of the as-synthesized MAPbCl3 single crystal were also investigated by the Hall and Current- Voltage measurements. The MAPbCl3 single crystals were synthesized using the inverse temperature crystallization method. The crystals were free from remaining precursors as demonstrated in the Raman spectra. We investigated the changes in optical properties accompanied with the phase transitions occurred in crystal lattice structures between wide temperatures ranged from 300 K to 20 K. Temperature-dependent X-ray diffraction studies revealed phase transitions from cubic to tetragonal phase at 180 K and from tetragonal to orthorhombic phase at 175 K. At 300 K, the major peak at ~ 3.07 eV in the photoluminescence spectrum was asymmetric in line shape with a weak and broad shoulder near the absorption edge as in the case of the MAPbBr3 single crystals. The broad shoulder was attributed to the presence of the ‘Cl’ atoms vacancy on the surface of crystals. The photoluminescence intensity of the crystals was strongly attenuated under vacuum. However, the intensity could be fully recovered when the chamber pressure was restored. It indicated that the carrier recombination was affected by the desorption/absorption of gas molecules at the crystal surface. Moreover, measurements of temperature-dependent photoluminescence and absorption clearly indicated that the observed luminescence peaks from 300 K to 20 K were due to the band gap of MAPbCl3 single crystal. At a temperature lower than 145 K, multiple emission peaks were observed and they were attributed to co-exist of two different crystallographic phases, which is also evident in the temperature-dependent XRD measurements. Interesting, replicas below the band edge with energies resemble the vibration/rotation modes of the MA+ group were observed in the photoluminescence spectra when temperature was below 90 K. The origins of those replicas were attributed to the interactions between the vibration/rotation modes of the MA+ group and the excited electrons. Finally, the carrier concentrations (2.63×〖10〗^11 〖cm〗^(-3)), mobility ( 4.14

APA, Harvard, Vancouver, ISO, and other styles

39

Priante, Davide. "The Recombination Mechanism and True Green Amplified Spontaneous Emission in CH3NH3PbBr3 Perovskite." Thesis, 2015. http://hdl.handle.net/10754/576012.

Full text

Abstract:

True-green wavelength emitters at 555 nm are currently dominated by III-V semiconductor-based inorganic materials. Nevertheless, due to high lattice- and thermal-mismatch, the overall power efficiency in this range tends to decline for high current density showing the so-called efficiency droop in the green region (“green gap”). In order to fill the research green gap, this thesis examines the low cost solution-processability of organometal halide perovskites, which presents a unique opportunity for light-emitting devices in the green-yellow region owing to their superior photophysic properties such as high photoluminescence quantum efficiency, small capture cross section of defect states as well as optical bandgap tunability across the visible light regime. Specifically, the mechanisms of radiative recombination in a CH3NH3PbBr3 hybrid perovskite material were investigated using low-temperature, power-dependent (77 K), temperature-dependent photoluminescence (PL) measurements. We noted three recombination peaks at 77K, one of which originated from bulk defect states, and other two from surface defect states. The latter were identified as bound-excitonic (BE) radiative transitions related to particle size inhomogeneity or grain size induced surface state in the sample. Both transitions led to PL spectra broadening as a result of concurrent blue- and red-shifts of these excitonic peaks. The blue-shift is most likely due to the Burstein-Moss (band filling) effect. Interestingly, the red-shift of the second excitonic peak becomes pronounced with increasing temperature leading to a true-green wavelength of 553 nm for CH3NH3PbBr3. On the other hand, red-shifted peak originates from the strong absorption in the second excitonic peak owed to the high density of surface states and carrier filling of these states due to the excitation from the first excitonic recombination. We also achieved amplified spontaneous emission around excitation threshold energy of 350 μJ/cm2 when optically pumped using 475 nm laser pulses, thus supporting the assignment of carrier absorption and re-excitation mentioned above. This dissertation work led to the following article: D. Priante, I. Dursun, M. S. Alias, D. Shi, V. A. Melnikov, T. K. Ng, O. F. Mohammed, O. M. Bakr, and B. S. Ooi, "The recombination mechanisms leading to amplified spontaneous emission at the true-green wavelength in CH3NH3PbBr3 perovskites", Applied Physics Letters, 106, 081902, 2015. DOI: 10.1063/1.4913463

APA, Harvard, Vancouver, ISO, and other styles

40

Lu, Yi Chen, and 盧宜蓁. "The influence of dichlorobenzene / chlorobenzene ( DCB / CB ) containing electron transport layer ( [6,6]-phenyl-C61-butyric acid methyl ester, PC61BM ) precursor solution on the structural and optical properties of perovskite-based ( CH3NH3PbBr3 ) optoelectronic devices." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/re67a5.

Full text

Abstract:

碩士
長庚大學
電子工程學系
105
Nowadays, the photovoltaic efficiency of perovskite-based solar cells has been boost up to the value of more than 20%; experimentally, owing to low manufacturing cost and simple process, the feasibility of mass production of such cells becomes anticipated. In addition to being used in renewable energy fields, they can also be used for optoelectronic devices as material engineering is conducted to optimize the grain size of perovskite-based thin films with reduced defect density. The structure of perovskite device in research is ITO / PEDOT:PSS / Perovskite / PC61BM / Ag. We shall devote to improve the luminous efficiency of perovskite-based LEDs through optimizing the structural properties of perovskite thin films with reduced defect density. In addition, the interfacial behavior between the electron injection layer and the perovskite thin film can be reinforced through solvent annealing processes. In the experiment, several facilities such as scanning electron microscope, X-ray diffractometer, and electroluminescence spectrum will be used to investigate the optical, electrical, structural and excitonic properties of perovskite-based thin films synthesized with different electron transport layer PC61BM precursor solution processes. When the electron transport layer PC61BM precursor solution contains 10% dichlorobenzene, showing the best film, photoelectric properties and the best crystal quality; the maximum current density of 5.16 mA / cm2, with the smallest ideal factor and series resistance were 10.5670Ω and 41.611Ω, and the maximum luminous brightness of 9.3x10-4cd / m2.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'CH3NH3PbI3'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles