Asymmetric Contact Induced Self-driven Perovskite Microwires Photodetectors

Photodetectors have been widely used in optical communication,environmental monitoring,medicine,industry and other military and national economic fields.In particular,self-driven photodetectors based on low-dimensional materials have become a research hotspot due to their advantages of low power consumption and high performance.Perovskite microwires/nanowires not only have the advantages of one-dimensional geometric structure such as excellent anti-reflection ability and mechanical flexibility of,but also have the photoelectric properties of hybrid perovskite materials,such as strong optical absorption coefficient and long carrier diffusion length.Therefore,they have recently attracted particular attentions for a variety of optoelectronic device applications.Herein,a self-driven photodetector based on CH3NH3PbI3 perovskite microwires is prepared by a simple one-step method,and its working principle has been discussed in depth.The specific details are as follows:1.Perovskite microwires with uniform distribution and good crystallization were prepared by one-step self-assembly method induced by solvent evaporation.Photodetectors were then fabricated by vaporizing metal electrode pairs with different work functions at both ends of microwires by electron beam evaporation.The photoelectric characterization shows that the device has obvious photovoltaic activities with the max open-circuit voltage 0.62 V and the short-circuit current 0.57 nA.2.The photodetection performance has been deeply researched.The devices show excellent photoresponse over the range 380-900 nm,showing the great potential as a self-driven visible light photodetector.A typical device shows responsivity of 161.1 mA/W and a fast response speed of 13.8/16.1 ?s under 520 nm illumination.In addition,the dark current was low to tens of femtoamps,enabling a high specific detectivity of 1.3×1012 Jones.3.A flexible photodetector have been successfully prepared on a flexible substrate PET,which shows comparable photoresponse performance and outstanding flexibility and bending durability.The asymmetric contact induced self-driven perovskite microwires photodetector has a simple device structure and good device performance,providing an opportunity for future highly sensitive and low energy consumption photodetection systems.