Enhanced performance of solution-processed all-inorganic halide perovskite photodetectors by using bulk heterojunction and lateral configuration

Currently, all-inorganic halide perovskites are widely investigated for their applications in optoelectronics due to their excellent physical and chemical properties. In this paper, solution-processed bulk-heterojunction lateral photodetectors Ag/CsPbBr₃:ZnO/Ag were built to enhance device performance, in which the active CsPbBr₃ layer were surface-passivated by ZnO nanoparticles (NPs) in an optimized molar ratio. By optimizing the molar ratio of CsPbBr₃ to ZnO NPs (i.e. k_R=M_CsPbBr3/M_ZnO), the photocurrent from the lateral photodetector was greatly enhanced and, the dark current was suppressed to as low as 10⁻¹² A due to the lateral configuration by employing a 50 µm-width active layer made through an interdigital mask. As a result, the On/Off current ratio of the lateral photodetector Ag/CsPbBr₃:ZnO/Ag reaches to more than 10³ for an optimum molar ratio k_R= 1:1, and it is 300-folds higher than that of the control device Ag/CsPbBr₃/Ag, showing a maximum specific detectivity D* of 1.6 × 10¹¹ Jones with a photoresponsivity of 3.8 mA/W under 16 µW/cm² 405 nm illumination at − 5 V. In this way, it provides an efficient method for solution-processed high-performance photodetectors by combining bulk heterojunction and lateral configuration.