Research And Implementation Of CsPbX₃ Perovskite And Application Of Photoelectric Devices

Photoelectric detection is widely used in military and civilian fields.However,photodetectors prepared by traditional inorganic semiconductor materials are usually expensive and require complex process.In recent years,halide perovskites have drawn great attention due to their high light absorption coefficient,large carrier diffusion length,strong photoluminescence intensity,extremely low non-radiative charge recombination,low cost and simple preparation process.Except for the above-mentioned merits,all-inorganic perovskites CsPbX₃?X=I,Br,and Cl?also possess a good light and thermal stability,which are considered to be the most promising strategies to overcome the hybrid PSCs'stability issues.In this paper,we used a low-temperature method to fabricate inorganic perovskites photodetectors,which mainly focuses on solving the problems such as high-driving voltage,slow response time?ms?,and narrowband.The paper also systematically introduced the fabrication of all inorganic perovskite CsPb(I_1-xBr_x)₃ films,photodetector devices and flexible applications.The details of studies are as follows:1.Firstly,we optimized the ratios of solvents andmaterials,spinning speed and time,different anti-solvent techniques.In addition,we changed the band gaps of CsPb(I_1-xBr_x)₃by adjusting the proportion of bromine in precursor solutions to absorb most visible light,which would induce the absorption peaks display some red shifts or blue shifts.Then the fabricated perovskite films was used as photolayers to form detector devices with a structure of vertical photoconductor.Operating at a quite low voltage bias of 10 mV,the perovskite photodetectors show a response speed to microsecond,a high specific detectivity of 10⁹¹0¹⁰ Jones,the high switching ratios of 10³ to 10⁴.Kept in air atmosphere for one month,our device showed nearly consistent photocurrent response,indicating good stability.2.We used graphene to modify the CsPb(I_1-xBr_x)₃ photosensitive layers.Firstly,the dispersion process of graphene was studied.Different solvents including DMF,methanol,ethanol,ethylene glycol and deionized water were used to disperse graphene.According to compare the results,we chose DMF as the last dispersing agent,and adopted vacuum filtration method to prepare graphene.It is found that the device with graphene showed higher specific detectivities up to10¹⁰¹0¹¹ Jones,which is one or two orders of magnitude than the obtained value from the reference devices.Similarly,the modified devices showed a good environmental stability.3.Finally,we explored CsPb(I_1-xBr_x)₃ films for flexible perovskite photodetectors.the flexible devices exhibited a fast response speed,high specific detectivity of 10⁹ Jones to 10¹⁰ Jones and excellent mechanical stability.After being stored in ambient conditions for one month,the photocurrent performance showed a negligible change,confirming the flexible device has a good stability in ambient air.