Photoelectric Conversion Performance Study Of High Efficiency And Stable Cellulose Triacetate Composite Perovskite Solar Cells

Energy crisis and environmental pollution are serious global problems today.Therefore,the development of clean energy as a substitute for conventional energy is a major challenge for the world.Among many renewable energy sources,solar energy is highly regarded due to its inexhaustible and low impact on the environment.In the past fourteen years,organic-inorganic hybrid perovskite solar cells（PSCs）have made significant progress,with their power conversion efficiency（PCE）rapidly increasing from only 3.8%fourteen years ago to over 25%today.Although PSCs have made significant progress,non-radiative recombination and stability are one of the main factors limiting their further improvement in PCE.Non-radiative recombination can shorten the lifetime of charge carriers,reduce the photovoltaic conversion efficiency of devices,and affect the open-circuit voltage and fill factor of devices.Due to the instability of perovskite materials,they are prone to degradation and decomposition,leading to a decline in device performance.Therefore,overcoming non-radiative recombination and stability is an important research direction for improving PSCs performance.This article mainly focuses on improving the quality of the hole transport layer grains,improving the quality of the perovskite film deposition and stability,and studying the effect of surface potential and polarity on CH₃NH₃Pb I₃（MAPb I₃）-based solar cells.The main research content of the thesis is as follows:（1）By controlling the amount of NiO_x precursor,NiO_x films with a particle size distribution of 35nm are obtained,without any aggregation phenomenon,which improve the hole transport efficiency at the interface.The rinse time of the anti-solvent is controlled to adjust the surface defects of the perovskite film,reduce the production of broken grains,decrease the residual amount of anti-solvent,and thus improve the power conversion efficiency（PCE）of PSCs.（2）The structure of cellulose triacetate（CTA）-modified perovskite is characterized with the introduction of CTA optimized the deep-level defects at the perovskite grain boundaries,and make it more compatible with the energy levels of the hole transport layer（HTL）and electron transport layer（ETL）,thus increasing the mobility of electrons and holes.Fourier transform infrared（FTIR）show that CTA interacted with the perovskite,acting as a scaffold,and formed hydrogen bonds with it,increasing the electron density around Pb in the[Pb I6]^2-octahedron,which made the perovskite film more stable.A PSCs device based on CTA-modified MAPb I₃ film is prepared,with a photoelectric conversion efficiency of 19.64%.（3）Atomic force microscopy（AFM）is used to characterize the surface morphology of CTA-modified perovskite,and Kelvin probe force microscopy（KPFM）and piezoresponse force microscopy（PFM）are used to test the surface potential and polarization,respectively.KPFM results show that CTA can enhance the photoelectric response of the perovskite film,while PFM results indicate that CTA can suppress the reverse of ferroelectric domains,which have higher photoelectric current.The PCE of CTA modified PSCs is improved.