A Chiral Quasi-Two Dimension Perovskite For An Efficient Circularly Polarized Light Photodetector

Conventional circular polarized light detectors rely on optical elements such as linear polarizer and quarter waveplate.Such a complicated configuration does not meet the demands of miniaturization trends,which is also incompatible with the emerging wearable technology.Organic-inorganic halide perovskite has a wide application prospect in the field of optoelectronics due to its superior photoelectric properties.The introduction of chiral organic ammonium into the lattice endows the two-dimensional perovskite with the inherent chirality,making direct circular polarized light detection possible.However,two-dimensional perovskites suffer from strong electron-phonon coupling and inferior out-of-plane mobility,which introduced a nonradiative recombination pathway to deteriorate the semiconducting properties of the materials.Therefore,it is urgent to explore new chiral perovskite materials to improve circular polarized light detection efficiency.Quasi-two-dimensional perovskite is a promise candidate material because of its excellent semiconductor properties.This work thorough investigated the intrinsic property of chiral quasi-two-dimensional perovskite.Various optical and electrical characterizations,including grazing incidence wide-angle X-ray scattering?GIWAXS?,transient absorption?TA?,space-charge-limited current?SCLC?,time-resolved photoluminescence?TRPL?and hall-effect measurement,et al.were carried out.The new innovative solution lays the foundation for efficient,flexible and durable circular polarized light photodetectors.The chiral quasi-two-dimensional perovskite single crystals?[?R?-?-MPA]₂MAPb₂I₇ and[?S?-?-MPA]₂MAPb₂I₇?was grown by temperature cooling method,and its inherent chirality and detection ability for circular polarized light were investigated.We thus introduce reducing agent and surface thermal annealing process to increase the crystal quality,by removing defect states as much as possible.Corresponding circular polarized light detectors based on optimized quasi-two-dimensional perovskite single crystals demonstrate good capability to distinguish different polarization states of circular polarized light photons and outstanding detection performance.In particular,the device responsivity is almost one order of magnitude higher than the reported two-dimensional perovskite circular polarized light detectors to date.This result proves the great potential of realizing high-performance thin-film chiral quasi-two-dimensional perovskite film circular polarized light detectors.On this basis,chiral quasi-two-dimensional perovskite thin film was prepared by one-step spin coating method.The crystallization kinetics of the film was carefully modulated to facilitate the lateral-direction?in-plane?carrier transport.In addition,the regulate mechanism of crystallization kinetics was demonstrated in detail.Experiments show that parallel-oriented perovskite films with homogeneous energy landscape are crucial to maximize the carrier collection efficiency of the resulting photodetector.The responsivity and linear dynamic range of resulting flexible photodetector are comparable with the reported results to date.The device also exhibits superior mechanical flexibility and durability,representing a promising candidate for sensitive and robust circular polarized light photodetectors.