Preparation And Performance Of Self-powered Photodetector Based On MAPbBr₃ Microwire

Photodetectors have the ability to convert optical signals into electrical signals,and have been widely used in optical communication,imaging,environmental monitoring,biosensing and other fields.In recent years,halide perovskite materials have been regarded as one of the preferred materials for the preparation of high-performance optoelectronic devices due to their advantages such as adjustable band gap width,high carrier mobility,long carrier diffusion length,high light absorption coefficient,low exciton binding energy,low defect density and solution-processable properties.Among the various forms of perovskite materials,one-dimensional perovskite micron has excellent geometric structure,high specific surface area and one-dimensional domain limiting effect,which makes it one of the preferred objects for the preparation of high-performance photodetectors.From the perspective of application,if a photodetector can work without external power supply,also known as self-driven photodetector,it will have the advantages of energy saving,device miniaturization,suitable for extreme environment work,so it has a wide application prospect.Self-driven photodetectors have been fabricated by p-n junction,heterojunction and Schottky junction using photogenerating volt effect.In this paper,MAPb Br₃perovskite micron line was prepared by two-step method,and a self-driven photodetector based on Schottky structure and heterostructure was prepared by perovskite micron line,and its performance was discussed.The main research work is as follows:1.The PbBr₂micron wires were grown by anti-solvent assisted method as the initial skeleton,and the Pb Br₂was transformed into MAPb Br₃perovskite micron wires by ion incorporation process while maintaining the one-dimensional micron wires structure.A metal-semiconductor-metal（MSM）self-powered photodetector（Au/MAPb Br₃/Ag）based on perovskite micron line was constructed by electroplating metal electrodes（Au/Ag）with different work functions at both ends of perovskite micron line by resistance thermal evaporation method.Due to the different work functions of Au and Ag electrodes,an asymmetric Schottky barrier is formed at the interface of the two electrodes,which finally results in the obvious photovoltaic effect of the device and realizes the self-driven working mode.The peak responsivity of the device is 1.14 m A/W at 530 nm at 0 V.The I-t test shows that the device has a switching ratio of 1.35×10~2and good stability at 0 V bias voltage.In addition,the device has a fast response time,with a rise time of 11μs and a decay time of 640μs.2.Based on the two-step growth of MAPbBr₃micron wires,PTAA was selected as p-type semiconductor material and coated on one end of MAPb Br₃micron wires by the coating process to construct MAPb Br₃/PTAA heterojunction photodetector.The peak responsivity of the device at 540 nm is 0.25 m A/W at 0 V working bias.The I-t test shows that the device has a switching ratio of 1.39×10~2and good stability at 0 V bias voltage.In addition,the device has a fast response time,with a rise time of 11μs and a decay time of 660μs.