X-ray Detector And Near-infrared Photodetector Based On CH₃NH₃PbI₃ Polycrystalline Wafer Prepared By Hot Pressing Method

The organic-inorganic perovskite material CH₃NH₃PbI₃（MAPbI₃）is promising for X-ray detectors and near-infrared photodetectors owing to its unique photoelectric properties.Nonetheless,it remains difficult to prepare high-quality MAPbI₃crystals,which severely limits the potential application of this material.In this study,high-quality MAPbI₃multicrystalline wafers are prepared by hot pressing method,with small-size MAPbI₃single crystal as raw material which have been successfully applied to the field of X-ray detectors and near-infrared photodetectors.The primary research contents are as follows:（1）In this paper,MAPbI₃multi-wafers are prepared employing hot pressing method,as well as the effects of temperature（150°C and 100°C）and holding time（20 min,30 min and 40 min）on the crystal quality of multi-wafers are systematically explored.It can be found that when the wafer preparation temperature is 150°C and the holding time is 30 min,MAPbI₃multi-wafer exhibits satisfying crystal quality.The lattice structure of multi-wafer is a pure tetragonal phase of MAPbI₃.Moreover,the wafer is compact,pinhole-free,and has a hardness of approximate 0.47 GPa.On this basis,this study prepares X-ray detectors and near-infrared photodetectors with Au/MAPbI₃/Au planar interdigital structure.（2）The performance of the X-ray detector with Au/MAPbI₃/Au planar interfinger structure is studied.The carrier mobility and lifetime product of this MAPbI₃multi-die is 7.2×10^-4cm²V^-1.The device achieves a sensitivity of 3.1×10⁵μC Gy^-1cm^-2at a bias voltage of 5 V and a dose rate of routine medical diagnosis of 5.5μGy^-1.In addition,such a device has been employed to achieve X-ray imaging of metal keys and the lumbar spine of mice.（3）The near-infrared photoelectric detection research is conducted on Au/MAPbI₃/Au planar interfinger structure.The device possesses a maximum responsivity of 2.1 A/W at a 5V bias voltage,corresponding to external quantum efficiencies of 332.36%and 1.5×10¹²Jones,respectively.The ramp-up and decay response times are 239μs and 6.13 ms,respectively.In addition,this device has made a significant contribution to the biomedical imaging of mouse viscera.