Research On Low-temperature Preparation And Optoelectronic Properties Of Key Materials For Planar Heterojunction Perovskite Solar Cells

Organic-inorganic hybrid perovskite materials have drawn increasing attention for its outstanding performance in terms of light absorption coefficient,diffusion length of carriers and processing technology.The photoelectric conversion efficiency of perovskite solar cells(PSCs)has grown from the initial 3.8%to 22.1%for only a few years,showing a bright future of commercialization.Based on the understanding of research status of perovskite solar cells,this paper conducted some research in three aspects:the way to optimize the component of perovskite,prepare high-performance electron transport layer at low temperature and eliminate the hysteresis effect of perovskite device.First of all,this paper investigated the optimum conditions for the preparation of(FAPbI3)x(MAPbCl3)1-x mixed perovskite by two-step method.The drying temperature and time of PbI2 precursor,the rotation speed of PbI2 precursor and FA+/MA+ mixed solution and the annealing process were explored,which can affect the grain size,surface morphology and composition of perovskite film.Thus,the optimum preparation process of perovskite thin films was determined.Secondly,focused on the research on the synthesis of high-performance electron transport materials under low temperature and atmospheric pressure,this paper developed a water-soluble anatase TiO2 nanocrystals prepared by sol-gel method,which can be made into annealed-free TiO2 nanocrystalline film with excellent photoelectric properties at room-temperature.Then,the effect of different nanocrystalline thickness on the performance of planar heterojunction PSCs was investigated by combining the preparation process of the absorption layer,and the optimum thickness of the nanocrystalline film was determined.Finally,in order to eliminate the inherent hysteresis effect of PSCs,this paper attempted to dope CuIn(SxSe1-x)2 series nanoparticles into perovskite materials.Previously,extremely stabilized CuIn(SxSe1-x)2 nanoparticles with suitable band gap were prepared by adjusting the S/Se relative ratio in reactants by hot injection method,and the remaining oleylamine in the product was replaced by acetylacetone.Subsequently,the obtained nanoparticles were doped into perovskite materials to assemble devices and the effect of the relative S/Se ratio of CuIn(SxSe1-x)2 nanoparticles and residual complexing agents on the performance of perovskite films and PSCs was studied.