Research On High Performance Photodetector Based On MAPbI₃ Perovskite Material

As important equipment for modern information acquisition,photodetectors can convert optical signals into electrical signals and play an indispensable role in the fields of optical communication,environmental monitoring,machine vision,and image sensing.In recent years,organic-inorganic hybrid perovskite materials have become a research hotspot in the field of photodetectors with the advantages of high optical absorption coefficient,long exciton diffusion length,high carrier mobility,and adjustable bandgap.However,due to the limitations of materials,the development of perovskite photodetectors also faces various realistic resistance,including:（1）the preparation process needs to rely on inert gas protection,which increases the device preparation cost;（2）The preparation process is accompanied by the use of toxic reagents,which increases the risk of device preparation;（3）There are a lot of crystal defects in perovskite polycrystalline films,which seriously limit the improvement of device performance;（4）The absorption spectrum of perovskite films is limited to the visible range,which seriously limits the spectral detection range of devices.Based on the above status,this topic has carried out relevant research,and the specific work is as follows.（1）An effective antisolvent-assisted nucleation management strategy is proposed to explore the preparation of high-performance perovskite photodetectors in the low-humidity air environment.The results show that the perovskite films prepared in air environment with tert-butanol antisolvent have uniformity,smooth surface,no pinhole,and large grain size.In addition,under the irradiation of 532 nm laser with 5μW cm^-2power density,the tert-butyl alcohol-based perovskite photodetector shows a high responsivity of 1.93 A W^-1,high specific detectivity of 7.62×10¹¹Jones.The responsivity of this photodetector is the highest among the same vertical device structures and even significantly exceeds some reported perovskite devices prepared in an inert atmosphere.（2）A strategy based on NIR-sensitive PTB7-Th:COTIC-4F organic bulk heterojunction is proposed for extending the response spectrum of perovskite photodetectors to achieve highly sensitive detection covering the visible to NIR spectrum.The results show that PTB7-Th:COTIC-4F can effectively passivate the defect states in the perovskite polycrystalline films,improve the film quality of perovskite and further reduce the dark current level of the devices.The photodetector based on MAPb I₃/PTB7-Th:COTIC-4F material achieved high responsivity of 0.58 A W^-1,1.19 A W^-1and 1.41 A W^-1,high specific detectivity of 1.64×10¹² Jones,3.38×10¹²Jones,and 3.99×10¹² Jones under 532 nm,808 nm,and 980 nm wavelength irradiation,respectively.This study provides an important reference for the preparation of broad-spectrum and high-performance perovskite photodetectors.