Research On Inorganic Lead Halide Perovskite Photodetector

In recent years,organic-inorganic hybrid perovskite has developed rapidly in the field of photovoltaic application,but in the field of photodetection,due to its instability in hot and humid environment,further development is limited.Inorganic lead halide perovskite has both superior stability and excellent photoelectric properties same as organic-inorganic hybrid perovskite,which makes it become one of the hot spots in the field of photoelectric device research.However,due to the poor film quality,the performance of the photodetectors based on inorganic lead halide perovskite still lags behind that of organic-inorganic hybrid perovskite photodetectors.In this paper,typical inorganic lead halide perovskite materials CsPbBr₃ and CsPbCl₃ were selected to explore the film solution spin coating process and the method of film quality optimization through experimental methods.Based on the structure of planar heterojunction photodetector and centering on the core performance parameters of photodetector,the optimization method of device performance improvement and the internal structure-activity relationship and mechanism between performance improvement and film quality were studied in depth.1)According to the test requirements of self-powered photodetector,the spectral response test system and frequency characteristic test system were designed and built.The system met the photoelectric response test requirements of devices in the range of 300 nm-1100 nm,and realized the measurement of basic core performance parameters of devices.2)In order to solve the problem that CsBr,the precursor of CsPbBr₃ film,has low solubility in common solvents and is difficult to prepare high quality films,we propose a method of intermediate phase halid exchange.Hence,the uniformly flat,compact,and pure-phase CsPbBr₃ film composed of[100]preferential,microsized grains can be achieved.Based on the above films,the carbon based,all-inorganic photodetector has excellent performance.The maximum responsivity(R)and the peak value of the D^*are 0.35 A W^-1 and 1.94×10¹²Jones,respectively,and the response time is 0.58?s.3)The method of PEAI sacrificial assisted CsPbBr₃ film growth in CsPbBr₃ inorganic perovskite system was proposed for the first time to further improve the film quality and form a CsBr-rich region on the film surface,thereby reducing the surface conductivity and further improving the device performance.The minimum dark current density of the self-powered photodetector based on this method is 8.05×10¹¹ A cm^-2,the maximum responsivity(R)and the peak value of the D^*are 0.35 A W^-1 and 3.83×10¹³ Jones,respectively,and the response time is 1.46?s.4)High quality dual-phase CsPbCl₃-Cs₄PbCl₆ thin films have been successfully prepared by intermediate phase halide exchange,and a self-powered visble-blind UV photodetector is realized based on the above thin films.The formation mechanism of the dual-phase thin films and the structure-activity relationship with the performance improvement of the device have been described.The obtained PDs has a simple structure,a full solution preparation process,a UV response range(310 nm-420 nm),a maximum responsivity(R)and a peak value of D^*are 61.8 m A W^-1 and 1.35×10¹² Jones,respectively,a quick response time of2.1/5.3?s,and excellent stability in air.