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High charge carrier mobility in solution processed one-dimensional lead halide perovskite single crystals and their application as photodetectors
摘要： Organic inorganic hybrid metal halide perovskites have emerged as promising candidates for photovoltaics and light-emitting diodes. Recently, interest has been growing in the properties of low-dimensional metal halide perovskites, and one-dimensional versions with strong quantum confinement have demonstrated highly efficient broadband luminescence. Nevertheless, the charge transport mechanism in these low dimensional perovskites remains unclear. In this work, we characterised the charge mobility in one-dimensional perovskite single crystals using a space charge limited current method. Temperature dependent charge mobility measurements indicated that localized polarons at high temperature are replaced by delocalized polarons at low temperature with extended states in the polaronic band. A minimum mobility of 4.51 cm2/Vs was measured at room temperature. UV photodetectors based on these crystals show an ultrahigh photoresponsivity of 132.3 A W-1. These findings show the promise of high mobility low dimensional perovskite materials for optoelectronic applications.
关键词： space charge limited current,low-dimensional,charge transport,photodetectors,organic-inorganic hybrid metal halide perovskites
更新于2025-09-19 17:13:59
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Engineering Multiphase Metal Halide Perovskites Thin Films for Stable and Efficient Solar Cells
摘要： The intrinsic instability of lead halide perovskite semiconductors in an ambient atmosphere is one of the most critical issues that impedes perovskite solar cell commercialization. To overcome it, the use of bulky organic spacers has emerged as a promising solution. The resulting perovskite thin films present complex morphologies, difficult to predict, which can directly affect the device efficiency. Here, by combining in-depth morphological and spectroscopic characterization, it is shown that both the ionic size and the relative concentration of the organic cation, drive the integration of bulky organic cations into the crystal unit cell and the thin film, inducing different perovskite phases and different vertical distribution, then causing a significant change in the final thin film morphology. Based on these studies, a fine-engineered perovskite is constructed by employing two different large cations, namely, ethyl ammonium and butyl ammonium. The first one takes part in the 3D perovskite phase formation, the second one works as a surface modifier by forming a passivating layer on top of the thin film. Together they lead to improved photovoltaic performance and device stability when tested in air under continuous illumination. These findings propose a general approach to achieve reliability in perovskite-based optoelectronic devices.
关键词： stability,solar cells,metal halide perovskites,bulky cations,mixed dimension
更新于2025-09-16 10:30:52
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Dark sub-gap states in metal-halide perovskites revealed by coherent multidimensional spectroscopy
摘要： Metal-halide perovskites show excellent properties for photovoltaic and optoelectronic applications, with power conversion efficiencies of solar cell and LEDs exceeding 20%. Being solution processed, these polycrystalline materials likely contain a large density of defects compared to melt-grown semiconductors. Surprisingly, typical effects from defects (absorption below the bandgap, low fill factor and open circuit voltage in devices, strong non-radiative recombination) are not observed. In this work, we study thin films of metal-halide perovskites CH3NH3PbX3 (X = Br,I) with ultrafast multidimensional optical spectroscopy to resolve the dynamics of band and defect states. We observe a shared ground state between the band-edge transitions and a continuum of sub-bandgap states, which extends at least 350 meV below the band edge). We explain the comparatively large bleaching of the dark sub-bandgap states with oscillator strength borrowing from the band-edge transition. Our results show that upon valence to conduction band excitation such sub-gap states are instantaneously bleached for large parts of the carrier lifetime and conversely, that almost dark sub-bandgap states can be populated by light excitation. This observation helps unraveling the photophysical origin of the unexpected optoelectronic properties of these materials.
关键词： photovoltaic,defect states,metal-halide perovskites,optoelectronic,ultrafast multidimensional optical spectroscopy
更新于2025-09-12 10:27:22
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Recent developments in flexible photodetectors based on metal halide perovskite
摘要： Flexible photodetectors (FPDs) have been receiving increasing attention in recent years because of their potential applications in electronic eyes, bioinspired sensing, smart textiles, and wearable devices. Moreover, metal halide perovskites (MHPs) with outstanding optical and electrical properties, good mechanical flexibility, low-cost and low-temperature solution-processed fabrication have become promising candidates as light harvesting materials in FPDs. Herein, we comprehensively review the developments of FPDs based on MHPs reported recently. This review firstly provides an introduction with respect to the performance parameters and device configurations of perovskite photodetectors, followed by the specific requirements of FPDs including substrate and electrode materials. Next, chemical compositions, structures and preparation methods of MHPs are presented. Then, the FPDs on the basis of single-component perovskite and hybrid structure perovskite are discussed, subsequently, self-powered flexible perovskite photodetectors were presented. In the end, conclusions and challenges are put forward in the field of FPDs based on perovskites.
关键词： metal halide perovskites,flexible photodetectors,self-powered
更新于2025-09-11 14:15:04