Preparation And Performance Of X-ray Detector Based On Stable Lead-free Perovskite Single Crystal

In the last decade,research on organic-inorganic halide perovskite materials that can be used in photovoltaic and optoelectronic devices has increased dramatically.A photodetector is a device that converts an optical signal into another form of signal.Most light detectors convert optical signals into electrical signals,which are then further processed or stored as current or voltage.Halide perovskite single crystals possess excellent photovoltaic and photoconversion properties and can be obtained by using relatively inexpensive pharmaceutical products through simple solution preparation techniques.However,the chemical structure and physicochemical stability of halide perovskite based on lead are poor,which affects its commercial use.Therefore,the development of new perovskite materials which are lead-free,non-toxic,with good structural safety and excellent electrochemical stability is the focus of current research and development.Perovskite single crystals can be prepared into light detectors and X-ray detectors.X-ray detectors can be widely used in daily life.However,X-ray has ionizing radiation that can cause harm to the human body.If the human body receives excessive and long-term X irradiation,it will cause radioactive damage to the human body,which will cause leukemia or carcinogenesis in serious cases.In daily medical diagnosis,doctors usually increase the radiation dose to achieve early diagnosis of diseases in pursuit of clearer imaging.So we want to achieve both radiation safety and a clear enough image.The primary task is to develop X-ray detectors with low detection limits,which can reduce radiation damage and achieve clearer,more accurate and faster imaging.In order to solve these problems,with the goal of exploring a new type of lead-free perovskite single crystal,the research work of a new type of lead-free perovskite single crystal with good stability from the aspects of crystal structure,photoelectric properties,X-ray detection preparation and research is as follows:1.designed and prepared large-size AG₃Bi₂I₉single crystal with shorter interlayer distance and a large mobility lifetime product of 7.94×10^-3cm²V^-1.With a high sensitivity of 5791 u C Gy^-1cm^-2,a low detection limit of 2.6 n Gy s^-1,and a short response time of 690μs,the combination of high sensitivity and high stability enables high spatial resolution(8.7 lp mm^-1)X-ray imaging.2.Lead-free MAGe I₃single crystals were obtained and prepared into X-ray detectors.The high volume resistivity of 2.36×10¹¹Ωcm,the high sensitivity of 481 u C Gy^-1cm^-2and the low detection limit of 143 n Gys^-1are realized.The X-ray detector with high sensitivity and low detection limit meets requirements.