Research On Perovskite Battery Devices Used In High-power Monochromatic Light Conversion

Laser photovoltaics,are special devices that convert laser energy(or monochromatic-light with high energy density)into electric energy.These devices are the core of laser wireless energy transmission technology for their significant research values and wide application prospects.At present,there is no relevant theoretical research starting from material plane,and the researchers mainly focus on the efficiency test and device optimization design based on III-V semiconductor materials(e.g.GaAs).There are two critical characteristics of the laser photovoltaics:band edge absorption and high injection,which are determined by the physical mechanism of this device.Fortunately,perovskite materials exactly meet the demands of laser photovoltaics for their excellent characteristics,such as ideal direct band gap,high density of band states and high optical absorption coefficient as well as long carrier life etc.,and all this makes it more potential for monochromatic-light energy conversion applications.Based on the organic-inorganic hybrid halide perovskite materials and devices,the monochromatic-light power conversion characteristics of perovskite materials and devices have been systematically studied in this thesis.Firstly,some basic theories are introduced including the physical mechanism of laser photovoltaics and the advantages of perovskite materials.Based on the energy band theory,the physical mechanism and important characteristics of laser photovoltaics are analyzed.As the results of literature investigation,the main advantages of organic-inorganic hybrid halide perovskite materials are revealed,which can be used in monochromatic-light power conversion.In order to match the band gap of perovskite materials with the specific laser wavelength,the study on the regulation of band gap of mixed-halide perovskite material(FA,MA)Pb(I,Br)3 is carried out in this thesis.The band gap of mixed-halide perovskite materials is controlled by adjusting the ratio of halide.The corresponding perovskite thin films and devices are prepared.By optical characterization of perovskite films and electrical measurements of the devices,it is achieved that the band gap can be regulated linearly varying from 1.55 eV to 1.8 eV for mixed-halide perovskite materials.Based on the results of band gap regulation,the monochromatic photo-electric conversion performance of perovskite devices is studied in this thesis.The photo-electric conversion characteristics of perovskite devices are systematically studied at specific wavelengths(683 nm,733 nm,786 nm).The response of monochromatic-light is analyzed near the band edge.We have obtained the spectral response characteristics of perovskite devices in the process of monochromatic-light power conversion.At the same time,the difference of monochromatic-light power conversion performance is studied under different energy density,and the variation rule of device performance parameters is obtained with the increase of monochromatic-light power.The main factors of perovskite device performance depression are analyzed under the condition of high energy density and we put forward the corresponding solutions.Under the condition of 683 nm,100 mW/cm2 monochromatic light irradiation,we have obtained the highest power conversion efficiency of 45%for perovskite devices.Considering the photovoltaic devices working under the condition of high energy density monochromatic light,the photostability has been studied for mixed-halide perovskite materials and devices under the specific wavelengths monochromatic-light,including the photo-induced degradation and phase separation of perovskite materials under high intensity monochromatic light.We analyze the main mechanism and influencing factors of photo-induced degradation and phase separation of perovskite under monochromatic light by means of transmittance and steady-state photoluminescence(PL)spectra,and a series of methods are given to restrain phase separation.Based on the organic-inorganic hybrid halide perovskite materials and devices,we have studied some of key topics systematically in this thesis,including the band gap regulation,spectral response characteristics for monochromatic-light energy conversion and the characteristics of photoelectric conversion as well as a series of problems of photostability.Many valuable conclusions have been obtained.It is hoped that the results of this thesis can be used for reference in the future research and development of monochromatic-light power conversion technology.