Studies Of Optical Properties And Photovoltaic Devices Of Quasi-Two-Dimensional Perovskite

Organometallic halide perovskite materials have excellent photoelectric properties such as small effect of defects,large absorption coefficient,large carrier diffusion length and adjustable band gap,and can be used to prepare solar cells and light-emitting devices.However,the perovskite itself also has many shortcomings,such as poor stability and immature preparation techniques,which limit their future commercial.Recently,two-dimensional metal halide perovskites have shown excellent stability compared to three-dimensional perovskites,which has attracted people's interest.This thesis takes two-dimensional perovskite as the research object,and mainly studies the influence of the preparation technology of the perovskite material on the performance of the device,the spectral properties of the perovskite film of(BA)₂(FA)₂Pb₃I₁₀(BA=CH₃(CH₂)₃NH₃,FA=HC(NH₂)₂)and the thermal decomposition mechanism of the perovskite materials.The specific work is introduced as follows:(1)Prepare(BA)₂(FA)₂Pb₃I₁₀ perovskite film and perovskite solar cell at different spin-coating speeds.The perovskite film was studied by XRD,ultraviolet absorption,and photoluminescence characterization methods;the performance parameters of the corresponding devices were measured by simulating the sunlight system and the Incident Photon-to-electron Conversion Efficiency system.In addition,we used SCAPs simulation software to simulate the device.Based on the above experimental results,it is found that the thickness of the(BA)₂(FA)₂Pb₃I₁₀ perovskite film decreases with the increase of speed,and the performance of the device also changes with the change of the preparation speed.Through comparative experiments,it is found that the preparation method of the heated substrate does significantly improve the short-circuit current and photoelectric conversion efficiency of the device,but the fill factor and open circuit voltage of the device are smaller than those prepared without heating the substrate,and it is found that under the condition of heating the substrate,the speed has no obvious effect on the performance of the device.(2)Prepare(BA)₂(FA)₂Pb₃I₁₀ films with different concentrations of precursor solutions and study their spectral properties.In addition,we prepared perovskite solar cells with different concentrations of precursor solutions and measured the performance parameters of the devices.Comprehensive experimental results found that the spectra of films prepared with different concentrations of precursor solutions showed regular changes.The concentration of the precursor solution has a significant impact on the performance of the device.When the concentration of the precursor solution is 0.25 mol/L,Perovskite solar cells show high PCE(Photoelectric Conversion Efficiency).(3)The stability of the two-dimensional perovskite film PEA₂(MA)_n-1Pb_nI_3n+1(PEA=C₆H₅(CH₂)₂NH₃,MA=CH₃NH₃)under different temperatures with glass and ITO as the substrate was studied.The experimental results show that the thermal stability of the PEA₂MA₂Pb₃I₁₀ film spin-coated on the glass substrate is obviously better than that of the perovskite spin-coated on the ITO substrate.The reason may be that the charge transfer between the substrate and the perovskite material leads to the poor thermal stability of the perovskite film.