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High Responsivity and High Rejection Ratio Self-Powered Solar-Blind Ultraviolet Photodetector Based on PEDOT:PSS/β-Ga2O3 Organic/Inorganic p-n Junction
摘要： A high responsivity self-powered solar-blind deep UV (DUV) photodetector with high rejection ratio was proposed based on inorganic/organic hybrid p-n junction. Owing to the high crystalized β-Ga2O3 and excellent transparent conductive polymer PEDOT:PSS, the device exhibited ultrahigh responsivity of 2.6 A/W at 245 nm with a sharp cut off wavelength at 255 nm without any power supply. The responsivity is much larger than that of previous solar-blind DUV photodetectors. Moreover, the device exhibited an ultrahigh solar-blind/UV rejection ratio (R245 nm /R280 nm) of 103, which is two orders of magnitude larger than the average value ever reported in Ga2O3-based solar-blind photodetectors. In addition, the photodetector shows a narrow band-pass response of only 17 nm in width. This work might be of great value in developing high wavelength selective DUV photodetector with respect to low cost for future energy-efficient photoelectric devices.
关键词： Self-Powered,PEDOT:PSS/β-Ga2O3,Plasmonics and Optoelectronics,Organic/Inorganic p-n Junction,Energy Conversion and Storage,High Rejection Ratio,High Responsivity,Solar-Blind Ultraviolet Photodetector
更新于2025-09-19 17:13:59
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Light or Heat: What Is Killing Lead Halide Perovskites Under Solar Cell Operation Conditions?
摘要： We report the first systematic assessment of intrinsic photothermal stability of a large panel of complex lead halides APbX3 incorporating different univalent cations (A=CH3NH3+, [NH2CHNH2]+, Cs+) and halogen anions (X=Br, I) using a series of analytical techniques such as UV-vis and x-ray photoelectron spectroscopy, x-ray diffraction, EDX analysis, atomic force and scanning electron microscopy, ESR spectroscopy and mass spectrometry. We show that heat stress and light soaking induce a severe degradation of perovskite films even in the absence of oxygen and moisture. The stability of complex lead halides increases in the order MAPbBr3<MAPbI3<FAPbI3<FAPbBr3<CsPbI3<CsPbBr3, thus featuring all-inorganic perovskites as the most promising absorbers for stable perovskite solar cells. An important correlation was found between the stability of the complex lead halides and the volatility of univalent cation halides incorporated in their structure. The established relationship provides useful guidelines for designing new complex metal halides with immensely improved stability.
关键词： Plasmonics and Optoelectronics,Photothermal Stability,Solar Cell Operation Conditions,Energy Conversion and Storage,Lead Halide Perovskites
更新于2025-09-12 10:27:22
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Self-Healing of Photocurrent Degradation in Perovskite Solar Cells: The Role of Defect-Trapped Excitons
摘要： Solution-processed lead halide perovskites have emerged as one of the most promising materials in optoelectronic applications. However, the perovskites are not stable over prolonged solar illumination. A recent experimental study has revealed light-activated photocurrent degradation and self-healing in the lead halide perovskites, which has important implications in tackling the photostability problems of the perovskites. Unfortunately, the physical origin of the experimental observations is unclear. In this work, we propose a first-principles theory which can elucidate all key experimental observations. By focusing on defect-trapped excitons, the theory can rationalize both fast and slow timescales of self-healing, contrasting dynamics of the photocurrent degradation and its recovery, and steep temperature dependence of the two competing processes. We further predict that the same phenomenon of self-healing could also be observed in other lead halide perovskites with even faster timescales of recovery. The work provides a general framework to elucidate defect-controlled excitation dynamics in perovskites.
关键词： Energy Conversion and Storage,Plasmonics and Optoelectronics
更新于2025-09-11 14:15:04
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Kinetic Monte Carlo Study of the Role of the Energetic Disorder on the Open-circuit Voltage in Polymer:Fullerene Solar Cells
摘要： One major factors limiting the e?ciency in organic solar cells (OSCs) is the low open-circuit voltage (Voc). Existing theoretical studies link the Voc with the charge transfer (CT) state and non-radiative recombination. However, also morphology and energetic disorder can have a strong impact on the Voc within realistic bulk-heterojunction OSCs. In this work, we present a kinetic Monte Carlo study on the role of the energetic disorder on the maximum Voc. We compute the quasi-Fermi level splitting for di?erent energetic disorder and analyze the impact of the energetic disorder at the donor-acceptor interface as well as correlations in the site energies on the Voc. Our results show that the interface strongly controls the maximum Voc. For a higher interface disorder, charge densities and non-geminate recombination increases, and the Voc is reduced. Furthermore, the correlated morphologies show an increase in the maximum Voc and a reduced impact of the energetic disorder.
关键词： Open-circuit Voltage,Kinetic Monte Carlo,Energy Conversion and Storage,Plasmonics and Optoelectronics,Polymer:Fullerene Solar Cells
更新于2025-09-11 14:15:04
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Dopants Control of Electron-Hole Recombination in Cesium-Titanium Halide Double Perovskite by Time Domain Ab Initio Simulation: Co-Doping Supersedes Mono-Doping
摘要： Using nonadiabatic (NA) molecular dynamics combined with time-domain density functional theory, we simulate electron-hole recombination in pristine and doped inorganic Pb-free double perovskite Cs2TiBr6. We show that replacing the titanium and/or bromine with silicon and/or chlorine extends the charge carrier lifetime. Importantly, dopants avoid deep traps despite they do not change the fundamental bandgap of Cs2TiBr6, they decrease the NA electron-phonon coupling and accelerate decoherence, arising from the reduced overlap of electron and hole wave functions as well as fast phonon modes induced by light dopants respectively, suppressing electron-hole recombination. More importantly, co-doping can reduce the formation energy of silicon and achieve higher doping concentration, potentially increasing the lifetime further. Our study suggests a rational strategy to reduce energy losses by co-doping in design of high performance all-inorganic Pb-free perovskite solar cells.
关键词： Co-doping,Electron-Hole Recombination,Mono-doping,Energy Conversion and Storage,Cesium-Titanium Halide Double Perovskite,Plasmonics and Optoelectronics,Time Domain Ab Initio Simulation,Dopants Control
更新于2025-09-10 09:29:36
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Effects of Electron-Phonon Coupling on Electronic Properties of Methylammonium Lead Iodide Perovskites
摘要： Temperature can have a dramatic effect on the solar efficiency of methylammonium lead iodide (CH3NH3PbI3) absorbers due to changes in the electronic structure of the system even within the range of stability of a single phase. Herein using first principles density functional theory, we investigate the electron band structure of the tetragonal and orthorhombic phases of CH3NH3PbI3 as a function of temperature. The electron-phonon interactions are computed to all orders using a Monte Carlo approach, which is needed considering that the second-order Allen-Heine-Cardona theory in electron-phonon coupling is not adequate. Our results show that the band gap increases with temperature in excellent agreement with experimental results. We verified that anharmonic effects are only important near the tetragonal-cubic phase transition temperature. We also found that temperature has a significant effect on the effective masses and Rashba coupling. At room temperature, electron–phonon coupling is found to enhance the band effective mass by a factor of two, and to diminish the Rashba coupling by the same factor compared to T=0 K values. Our results underscore the significant impact of electron-phonon coupling on electronic properties of the hybrid perovskites.
关键词： Energy Conversion and Storage,Methylammonium Lead Iodide Perovskites,Plasmonics and Optoelectronics,Electron-Phonon Coupling,Electronic Properties
更新于2025-09-10 09:29:36
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Rationalizing Perovskites Data for Machine Learning and Materials Design
摘要： Machine learning has been recently used for novel perovskite designs, owing to the availability of large amount of perovskite formability data. Trustworthy results should be based on the valid and reliable data that can reveal the nature of materials as much as possible. In this study, a procedure has been developed to identify the formability of perovskites for all the compounds with the stoichiometry of ABX3 and (A′A′′)(B′B′′)X6, that exist in experiments and are stored in the database of Materials Projects. Our results have enriched data of perovskite formability in a large extent and corrected the possible errors of previous data in ABO3 compounds. Furthermore, machine learning with multiple models approach have identified the A2B′B′′O6 compounds that have suspicious formability results in current experimental data. Therefore, further experimental validation experiments are called for. This work paves a way for cleaning perovskite formability data for reliable machine learning work in future.
关键词： Perovskites,Energy Conversion and Storage,Machine Learning,Plasmonics and Optoelectronics,Materials Design
更新于2025-09-09 09:28:46