Research Of Perovskite X-ray Optoelectronic Devices

X-ray detectors are used in a wide range of applications in radiation exposure monitoring,security screening,geophysics,and medical imaging with computed tomography（CT）.Perovskites and their derivatives show great promise in X-ray detection due to their high bulk resistivity,high photoluminescence quantum yield（PLQY）,suitable optical bandgap,simpler manufacturing processes than traditional semiconductor materials（Si、α-Se、CsI:Tl）and compatibility with integrated circuits.However,the poor stability of organic-inorganic perovskite materials in air and humid heat conditions restricts the commercial development of perovskite devices.All-inorganic halide perovskite materials have become a new focus of attention of researchers due to their excellent stability.In particular,they have high atomic numbers and high-quality elements（such as Pb,Br,and I）,which give them good ionizing radiation absorption capabilities.In addition,all-inorganic halide perovskites have inherently high carrier mobility,high stopping power,low detection limit,and radioluminescence（RL）,making them capable of radiation detection.Benefiting from these excellent properties,all-inorganic halide perovskites are considered as promising materials for X-ray detectors and scintillators.Therefore,this paper focuses on all-inorganic lead halide perovskites photodetector and X-ray detectors.The main research contents include:1.High-quality CsPb₂Br₅microwires were fabricated using a simple and environmentally friendly two-step self-assembly method.The influence of different substrate temperatures on the growth process of CsPb₂Br₅microwires was studied.The parasitic phase of CsPbBr₃ was discovered in CsPb₂Br₅by synchrotron wide-angle X-ray scattering（WAXS）.WAXS in-situ annealing test results show that CsPb₂Br₅microwires have good structural thermal stability.Spatially and time-resolved fluorescence measurements reveal the lifetime variation of CsPb₂Br₅microwires at different annealing temperatures,revealing the effect of annealing on the defect state and composition of the microwires.Photodetectors based on CsPb₂Br₅microwires exhibit good stability and relatively fast response times.2.Prepare CsPb₂Br₅microwires at a substrate temperature of 30℃.XPS qualitatively analyzed the constituent elements（Cs,Pband Br）and their valence states on the surface of CsPb₂Br₅microwires.Spatial and time-resolved fluorescence measurements reveal the fluorescence intensity distribution and defect states of microwires in different microdomains.Applying CsPb₂Br₅microwires to X-ray detectors,the X-ray detectors based on CsPb₂Br₅micron wires have relatively fast rise and fall times of 44 and 42 ms,respectively.The device exhibited an excellent sensitivity of 3490μC Gy_air^-1 cm^-2 and a minimum detectable dose rate of21.4μGy_air s^-1.And the CsPb₂Br₅X-ray detector exhibits high stability under X-rays.3.CsPbBr₃ nanosheets were prepared using a coprecipitation method in the air environment.Using Phthalic Diglycol Diacrylate（PDDA）to encapsulate CsPbBr₃ nanosheets,a uniform and shape-controllable flexible CsPbBr₃@PDDA thin film was prepared.The prepared film exhibits excellent optical properties.This paper studies the effect of different film thicknesses on the luminous intensity to determine what works best under X-rays.The changes of the luminous intensity of the CsPbBr₃@PDDA thin film in air and after repeated bending were tested,and the results showed that the prepared thin film had good environmental stability and flexibility.The flexible scintillator is applied to the convex lens,and the light-gathering effect of the convex lens is used to form an optical path,making the image of the scintillator brighter and clearer.