Research Of Photodetector Based On MAPbI₃ Single Crystalline Perovskite Wafer

In recent years,the perovskite semiconductor material has a wide applications in fields of photodetection and photovoltaics due to its high absorption coefficient,high carrier mobility,long carrier diffusion length and band engineering.At present,microcrystalline or polycrystalline perovskite films have been produced,and their properties are already excellent,but inevitably there are grain boundaries and surface defects,which will result in significant current-voltage?J-V?curve hysteresis,important optoelectronic performance such as carrier mobility is declining.However,the single crystal perovskite has lower trap density,longer carrier diffusion length,higher carrier mobility than polycrystalline counterparts,making it is an ideal material for preparing high performance optoelectronic devices..In this paper,MAPbI₃ single crystal perovskite wafer with a lateral dimension of 10 mm were successfully prepared by the combination of seed-induced crystallization and space-confined growth.In contrast,only a plurality of MAPbI₃ single crystal perovskite wafer having a size of less than 3 mm were obtained using space-confined growth.The prepared large size MAPbI₃ single crystal perovskite wafer have the trap density is only 2.36×10¹00 cm^-3,which is much lower than that of the polycrystalline counterparts.Further,a MAPbI₃ single crystal perovskite wafer photodetector was prepared,which exhibited a light on/off current ratio up to 4.3×10³,a response time of 770?s and a linear dynamic range?LDR?of 119 dB.At the lowest detectable illumination power density of80 nW/cm²,the device's external quantum efficiency?EQE?,responsivity?R?and detectivity?D*?were as high as 904%,3.87 A/W and 1.77×10¹³Jones,respectively.And at low temperatures the photodetector exhibits better photodetection performance than at room temperature.In addition,the device also has good stability,and the photocurrent is maintained above 80%of its original value after 30 days of storage in air.The results show that MAPbI₃ single crystal perovskite wafer photodetector may have wide applications in field of low light detection and low temperature detection.