Preparation And Research Of High Performance Perovskite/Organic Polymer Photodetectors

In recent years,perovskite materials have been widely used in optoelectronic components due to a series of advantages such as high light absorption coefficient,high carrier mobility,long carrier diffusion length,shallow defect level,and high crystallinity.The photodetector is an important photoelectric device that can convert light radiation signals into electrical signals,so it has significant application and scientific research value in military,civil and other fields.Semiconductor materials are an essential part of photodetectors.So far,many semiconductor materials have been used in photodetectors,including silicon,carbon nanotubes,III-V compounds,quantum dots,and remarkable progress has been made in improving light detection performance and device structure design.However,photodetectors based on these materials usually require expensive materials,rigorous processes,and complex manufacturing conditions,which hinder their commercial application.Optoelectronic devices based on perovskite materials have the advantages of the simple fabrication process,low cost,and high performance,making them widely concerned in optoelectronic applications.This paper focuses on the optimization and extension of the detection wavelength range for the hole transport layer of perovskite photodetectors.The research contents of this paper are as follows:（1）A small amount of Cs I is introduced into Spiro-OMe TAD together with Li-TFSI and TBP as additives.It is found that Cs I and TBP formed a complex,which inhibited the agglomeration of Li-TFSI in Spiro-OMe TAD,thus preventing the rapid evaporation of TBP from leaving some cracks Spiro-OMe TAD.The photodetectors exhibit broadband response from near-ultraviolet to near-infrared（300–800 nm）,achieving fast response（rise/fall time is54.1/10.7μs）and low dark current density(9.72×10^-10A cm^-2).The detector can be self-powered at zero bias voltage,the external quantum efficiency（EQE）is88%,the Responsivity（R）is 0.48 A W^-1,and the detectivity（D^*）is close to2.7×10¹³Jones.When the photovoltaic detector is placed in a nitrogen-filled glove box without special packaging for more than two months,the EQE remains 98.1%of the original.This study provides a simple method for fabricating a large area of high-performance planar perovskite detector（PD）.（2）By combining the characteristics of MAPb I₃material for near-ultraviolet-visible light and PDPP3T:PC71BM material for near-infrared light absorption,I fabricated a composite thin-film photodetector with a wide detection range from near-ultraviolet to near-infrared（NUV-vis-NIR）light.By optimizing the device structure,fabrication process,solute concentration,and polymer layer thickness,the composite thin-film photodetector obtained a high D^*of 1.24×10¹³jones,2.13×10¹³jones and 1.59×10¹³jones at near-ultraviolet（380 nm）,visible（655 nm）,and near-infrared（848 nm）,respectively.The composite thin-film detector exhibits a fast response speed（109/49μs）,a linear dynamic range of 100 d B,and excellent stability.In addition,the PDPP3T:PC71BM active layer can effectively suppress the leakage current in the reverse biased region and obtain an ultra-low dark current density(J_dark)of8.58×10^-10A cm^-2.This work opens a new avenue for developing high-performance photodetectors based on blends of perovskites and low-bandgap polymers.