The Study Of Preparation And Property Of Perovskite Film Applied In All Solid-State ZnO-TiO₂ Nanorod Arrays Solar Cells

The third generation solar cells were regarded as the effective measures to limit the environment pollution problem and the energy crisis problem which caused by the overusing of traditional fossil energy.Among the third generation solar cells,CH₃NH₃PbI₃ perovskite material is applied as absorb layer in the solar cells device due to its unique physics chemistry properties.In last decade,the power conversion efficiency?PCE?of perovskite solar cells?PSCs?has increase from 3.8%to 22.7%.Although the PCE increase fasting,the fabrication process of PSCs usually need high vacuum and the stability of PSCs has been disputed a lot,which limit the further application of PSCs in normal life.As the light harvesting layer in the solar cells,the quality of perovskite film is very important to the PCE and stability of the PSCs.This work first optimize the two-step preparation process of perovskite film and obtain high quality CH₃NH₃PbI₃ perovskite film successfully under ambient environment with relative humidity about 55%.We schematically study the effect of technological parameter in the two-step preparation process including the concentration of PbI₂ solution;the concentration of CH₃NH₃I solution;the anneal temperature and time of PbI₂ film and the the anneal temperature and time of CH₃NH₃PbI₃ perovskite film on the morphology,nano structure,optical property of the perovskite film and PCE of the PSCs.Furthermore,four different polymer additives were used to modify the perovskite film and obtain PSCs with enhanced efficiency.We schematically study the effect of variety and concentration of the polymers on the optical property of the perovskite film and PCE of the PSCs.Last but not least,we add PVP and PEG polymer into the PbI₂ solution to modify the perovskite film simultaneously and schematically study the effect of PVP-PEG additives on the morphology,nano structure,optical property of the perovskite film and PCE of the PSCs.The results shows that the specific parameters of two-step preparation process is relative to the PCE of PSCs.Meantime,the film shows the most red shift absorption edge and the highest absorption intensity.The PCE of the PSCs based on the optimized perovskite film reaches the highest.Moreover,after adding four kinds of different polymers?PVP;PEG;PAM and PVA?,the absorption edges of perovskite film show a various degrees of red shift,and the intensity of the light absorption in visible region also shows a different level of enhancement.When adding 3wt%PVP as polymer additives into the perovskite film,the PCE of the PSCs improved from 4.14%to 6.91%.Furthermore,while using both PVP and PEG as polymer additives into the perovskite film,the morphology of the perovskite film improve a lot,the film shows a more dense morphology and the amount of pin holes decrease obviously.While adding both PVP and PEG as polymer additives into the perovskite film,the film shows the best morphology.Moreover,the high intensity of the?110?peak shows the good crystallinity.The UV-vis absorption spectra show that the highest absorption intensify and the most red shift absorption edge,which is definitely benefit to the current density.The PCE of PSCs reaches the highest of a certain value of 7.52%.Furthermore,the unencapsulated device based on this two kinds of polymer modified perovskite film shows good stability.The PCE remains 90%after 700h store in ambient air.Meanwhile,after adding PbBr₂ into the PbI₂ precursor solution,the PCE of the PSCs increase to 8.74%.