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Optimization of Spin Coated TiO <sub/>2</sub> Layer for Hole-Free Perovskite Solar Cell
摘要： The optimization of the TiO2 layer in free-hole perovskite solar cells is critical, as it strongly affects the device performance. In this study, simple FTO/TiO2/CH3NH3PbI3/C solar cells were fabricated, via two-step dipping method, with different thickness of TiO2 layer. The structure and microstructure of the TiO2 layers were investigated by X-Ray diffraction (XRD), Raman spectroscopy, and UV spectroscopy (UV-vis). The effect of different TiO2 thickness on the structure and photovoltaic performance of the fabricated devices were investigated using XRD and IV measurement, respectively. The photovoltaic parameters, including short-circuit-current (Jsc), open-circuit-voltage (Voc), Fill factor (F.F) and power conversion efficiency (PCE), were found to be strongly dependent on the thickness of TiO2 layer. The investigation showed that, efficient device can be fabricated by optimizing the TiO2 thickness, employing a thickness of 108 nm as an optimum thickness in this study.
关键词： Perovskite,TiO2,CH3NH3PbI3,Solar cell
更新于2025-09-23 15:19:57
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Ultrafast acoustic phonon scattering in CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> revealed by femtosecond four-wave mixing
摘要： Carrier scattering processes are studied in CH3NH3PbI3 using temperature-dependent four-wave mixing experiments. Our results indicate that scattering by ionized impurities limits the interband dephasing time (T2) below 30 K, with strong electron-phonon scattering dominating at higher temperatures (with a time scale of 125 fs at 100 K). Our theoretical simulations provide quantitative agreement with the measured carrier scattering rate and show that the rate of acoustic phonon scattering is enhanced by strong spin-orbit coupling, which modifies the band-edge density of states. The Rashba coefficient extracted from fitting the experimental results (γc = 2 eV ?) is in agreement with calculations of the surface Rashba effect and recent experiments using the photogalvanic effect on thin films.
关键词： electron-phonon scattering,carrier scattering,CH3NH3PbI3,four-wave mixing,Rashba effect
更新于2025-09-19 17:13:59
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Influence of Electron Transport Layer (TiO2) Thickness and Its Doping Density on the Performance of CH3NH3PbI3-Based Planar Perovskite Solar Cells
摘要： Simulation studies are vital to understanding solar cell performance and in optimal device design for high-efficiency solar cells. Cell performance is sensitive to many factors, including device architecture, energy band alignment at the interfaces, materials used for photogeneration, charge extraction, doping density and thickness of various layers. The role of electron transport layer (ETL) thickness and its doping density on device performance is explored in this work. As the ETL thickness is increased from 10 nm to 200 nm, both fill factor (FF) and efficiency remain high up to 40 nm, at 0.85 and 28.04%, respectively, and beyond 40 nm, they decrease gradually due to a sharp increase in series resistance, reaching zero at 200 nm. However, Jsc and Voc remained unchanged up to an ETL thickness of about 150 nm and 160 nm, respectively. These results were confirmed by contour plots of the simulated Voc, Jsc, FF and efficiency results. We observed that when ETL approached 200 nm, Jsc and Voc decreased to zero and 0.88 V, respectively. This can be attributed to very high series resistance and recombination in the cell. Donor concentration variation in the ETL from 1017/cm3 to 1020/cm3 has much less impact on Jsc, and Voc remains unchanged. However, fill factor and efficiency improved, which might be due to an increase in conductivity in the ETL. Our result shows that for an optimized device, with an AM 1.5 spectrum, a cell efficiency of 29.64% was achieved with Voc, Jsc and fill factor of 1.241 V, 28.70 mA/cm2 and 0.83, respectively.
关键词： contour map,ETL doping density,light I–V,ETL thickness,CH3NH3PbI3
更新于2025-09-19 17:13:59
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Hot carrier extraction in CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> unveiled by pump-push-probe spectroscopy
摘要： Halide perovskites are promising materials for development in hot carrier (HC) solar cells, where the excess energy of above-bandgap photons is harvested before being wasted as heat to enhance device efficiency. Presently, HC separation and transfer processes at higher-energy states remain poorly understood. Here, we investigate the excited state dynamics in CH3NH3PbI3 using pump-push-probe spectroscopy. It has its intrinsic advantages for studying these dynamics over conventional transient spectroscopy, albeit complementary to one another. By exploiting the broad excited-state absorption characteristics, our findings reveal the transfer of HCs from these higher-energy states into bathophenanthroline (bphen), an energy selective organic acceptor far above perovskite’s band edges. Complete HC extraction is realized only after overcoming the interfacial barrier formed at the heterojunction, estimated to be between 1.01 and 1.08 eV above bphen’s lowest unoccupied molecular orbital level. The insights gained here are essential for the development of a new class of optoelectronics.
关键词： halide perovskites,CH3NH3PbI3,bathophenanthroline,pump-push-probe spectroscopy,hot carrier extraction
更新于2025-09-16 10:30:52
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Performance data of CH3NH3PbI3 Inverted Planar Perovskite Solar Cells via Ammonium Halide Additives
摘要： The data provided in this data set is the study of organic-inorganic hybrid perovskite solar cells fabricated through incorporating the small amounts of ammonium halide NH4X (X=F, Cl, Br, I) additives into a CH3NH3PbI3 (MAPbI3) perovskite solution and is published as “High-Performance CH3NH3PbI3 Inverted Planar Perovskite Solar Cells via Ammonium Halide Additives”, available in Journal of Industrial and Engineering Chemistry [1]. A compact and uniform perovskite absorber layer with large perovskite crystalline grains, is realized by simply incorporating small amounts of additives into precursor solutions, and utilizing the anti-solvent engineering technique to control the nucleation and growth of perovskite crystal, turning out the enhanced device efficiency (NH4F: 14.88 ± 0.33 %, NH4Cl: 16.63 ± 0.21 %, NH4Br: 16.64 ± 0.35 %, and NH4I: 17.28 ± 0.15 %) compared to that of a reference MAPbI3 device (Ref.: 12.95 ± 0.48 %). In addition, this simple technique of ammonium halide addition to precursor solutions increase the device reproducibility as well as long term stability.
关键词： perovskite grain size,inverted planar structure,CH3NH3PbI3 perovskite,ammonium halide additives,anti-solvent engineering
更新于2025-09-16 10:30:52
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Sequential deposition method of TiO <sub/>2</sub> /CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> films for solar cell application
摘要： Seeking to study innovative solar cell compositions with the goal to reach the highest energy efficiency level attainable, the aim of this study was to develop a route to obtain a solar cell composed by hybrid perovskite (CH3NH3PbI3) using a sequential deposition method through the techniques of spin-coating and immersion. Initially, the deposition of PbI2 thin film of was performed on a FTO/glass substrate coated with TiO2, which was subsequently converted into perovskite crystals through spin coating using a CH3NH3I solution. The influence of the PbI2 layer thickness on the formation of CH3NH3PbI3 crystals was evaluated. The hydrophilic characteristic of TiO2 affects the distribution of the crystals nucleation sites, since PbI2 possesses a non-polar liquid characteristic. The characterization of the perovskite thin films showed that thickness affects directly the bandgap and the surface morphology, revealing the presence of dendritic structures and acicular crystals. Both growth and coverage increased for thinner layers of PbI2. It was also possible to observe an increased uniformity in the film for smaller PbI2 layers.
关键词： solar cell,immersion,sequential deposition,TiO2,spin-coating,perovskite,CH3NH3PbI3
更新于2025-09-16 10:30:52
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Real time nanoplasmonic sensing for monitoring CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> perovskite formation in mesoporous TiO <sub/>2</sub> films
摘要： The formation of methylammonium lead iodide (CH3NH3PbI3) perovskite into mesoporous titania (TiO2) scaffold via a sequential deposition method is known to offer high quality films for good photovoltaic device performance. The local kinetics at the lower interface between the mesoporous TiO2 film and the collecting electrode govern perovskite growth and formation. Here, we have used a NanoPlasmonic Sensing (NPS) approach with gold (Au) nanosensors to monitor the formation of CH3NH3PbI3 perovskite at the lower interface of up to 650 nm mesoporous TiO2 films. This technique provides time-resolved spectral shifts of the localized surface plasmon resonance at different operating temperatures and methylammonium iodide (CH3NH3I3) concentrations by recording changes in the local vicinity of the Au nanosensors at the mesoporous TiO2 film interface. Analytical studies included ellipsometry, scanning electron microscopy, X-ray diffraction, and photoluminescence spectroscopy. The results show that both the intensity of the NPS response and NPS rate constants are correlated with the operating concentrations and temperatures of CH3NH3I3 as well as CH3NH3PbI3 perovskite growth in mesoporous TiO2.
关键词： nanoplasmonic sensing,localized surface plasmon resonance,mesoporous TiO2 films,perovskite formation,CH3NH3PbI3
更新于2025-09-16 10:30:52
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First-Principles Calculations of the Electronic and Optical Properties of CH 3 NH 3 PbI 3 for Photovoltaic Applications
摘要： Since the first efficient solid-state perovskite solar cells were reported in 2012, rapid development of the organic-inorganic hybrid halide perovskites has been made, and a new era in optoelectronic and solar cells technologies has emerged. The unique attributes of these hybrid halide perovskites make them highly promising materials for various practical applications including high performance in converting solar energy into electrical power, with very recent results demonstrating a 20.1% efficiency. However, the electronic and optical properties of these materials at low temperature have not been investigated extensively. Herein we analyse the electronic and optical properties of methyl-ammonium lead iodide perovskite, CH3NH3PbI3, using density functional theory (DFT) and many-body perturbation theory (MBPT). The electronic band gap and energy bands of CH3NH3PbI3 have been investigated using different density functional approximations with and without the effect of the spin orbit-coupling (SOC). Depending on the calculation method, we predicted the band gap to be in the range from 0.46 eV to 2.66 eV. In order to obtain optical spectra, we carried out Bethe-Salpeter equation (BSE) calculations on top of non-self-consistent G0W0 calculations. We have presented the absorption coefficient, refractive index and reflectivity to describe optical properties of the investigated material. The phase is found to be semi-conducting with a direct band gap in the visible range of the spectrum and strong optical absorption in the visible range.
关键词： optical properties,DFT,solar cell,CH3NH3PbI3
更新于2025-09-16 10:30:52
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Electronic and optical properties of two propounded compound in photovoltaic applications, CsPbI3 and CH3NH3PbI3: By DFT
摘要： Halide perovskite compounds are the serious contenders for conventional materials used in photovoltaic devices that will provide a bright future for solar cell industry. Therefore, preparing a comprehensive insight about their properties is necessary. In this regard, the electronic and optical studies of two important perovskite compound CsPbI3 and CH3NH3PbI3 in the cubic phase are performed by ?rst- principle method in Density Function Theory (DFT), using several approximations namely GGA, t-mbj and other types of t-mbj approximation with the tuned coef?cient including k-mbj and new mbj approximations. In addition to utilizing di?erent approximations, the e?ect of spin orbit coupling which is critical in these compounds, is evaluated in all of them to obtain realistic results. The band gaps calculated within new mbj approximation through spin orbit coupling are 1.34 eV and 1.49 eV for CsPbI3 and CH3NH3PbI3, respectively that unlike other DFT-based electronic calculations are in agreement with experimental results. Values of estimated e?ective masses of carriers represent lighter carriers for CH3NH3PbI3 in comparison to CsPbI3. Optical calculations of frequency dependent dielectric function con?rm non isotropic property in organic- inorganic perovskite CH3NH3PbI3 and estimate value of static refraction index equal to 2.47 which is in agreement with experimental measurements.
关键词： DFT,Optical properties,CsPbI3,CH3NH3PbI3,Photovoltaic applications
更新于2025-09-16 10:30:52
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Analysis of highly efficient perovskite solar cells with inorganic hole transport material
摘要： Organo-halide perovskites in planar heterojunction architecture have shown considerable promise as efficient light harvesters in solar cells. In this paper, a numerical modeling of a planar lead based perovskite solar cell (PSC) with Cu2ZnSnS4 (CZTS) as hole transporting material (HTM) has been done using one dimensional solar cell capacitance simulator (SCAPS-1D). The effects of numerous parameters such as defect density, thickness, and doping density of the absorber layer on the device performance are investigated. The doping densities and electron affinities of electron transporting material (ETM) and HTM are also varied to optimize the PSC performance. It has been observed that a thinner absorber layer of ~ 220 nm with a defect density of 1014 cm-3 compared to the reference structure improves the device performance. When doping density of the absorber layer increases beyond 2 × 1016 cm-3, the power conversion efficiency (PCE) reduces due to enhanced recombination rate. The defect density at the absorber/ETM interface reduces the PCE as well. Considering a series resistance of 5 Ωcm2 and all the optimum parameters of absorber, ETM and HTM layers simultaneously, the overall PCE of the device increases significantly. In comparison with the reference structure, the PCE of the optimized device has been increased from 12.76% to 22.70%, and hence the optimized CZTS based PSC is highly efficient.
关键词： CH3NH3PbI3,CZTS,SCAPS-1D,absorption coefficient
更新于2025-09-12 10:27:22