Doping Modification And Interface Optimization Of Tin-based Perovskite Solar Cells

With the global energy demand increasing,at the same time,people paying more attention to environmental protection,it has become an urgent and inevitable trend to develop clean and renewable energy source.Perovskite solar cells now become a research focus due to their excellent photoelectric properties and the promising development prospect as flexible electronics,which is in accordance with the current development trend of low carbon energy and environmental protection.However,currently the most efficient Pb-based perovskite olar cells are toxic,which restricts their commercialization.A large number of studies have proved that Sn-based perovskite is more in line with the development concept of clean and energy-saving due to its excellent photoelectric properties and non-toxic advantages,and is expected to replace traditional Pb-based perovskite as the development direction of perovskite solar cells.However,Sn-based perovskite batteries are prone to defects during the crystallization process,which seriously inhibits device performance.A lot of research is still needed to optimize them.In view of this problem,the specific work content of the paper is as follows:（1）Doping KBr in the precursor solution optimizes the optical performance of the device.In this study,potassium bromide（KBr）was selected to compare the performance of devices with different doping concentrations.It was found that doping with a smaller amount of KBr can help improve the morphology of the Sn perovskite film and effectively improve the surface quality of the perovskite film.The performance of titanium ore solar cells has also been improved.As the amount of KBr doped increases,it is found that excessive doping will inhibit device performance.Comparing KBr devices with different concentrations,the device showed the best performance when the doping concentration was 10%.Compared with the standard device,the open circuit voltage increased from0.32 V to 0.49 V,and the short circuit current increased from 6.02 m A·cm^-2 Increased to 10.67m A·cm^-2,the fill factor increased from 60.21%to 65.99%,and the device efficiency increased from1.16%to 3.45%of the standard.（2）Phenylethylamine iodine（PEAI）was choosed as dopant with different blend concentration into the antisolvent chlorobenzene,the（LDP）structure of PEA_xFA_1-xSn I₃ was formed.The introduction of PEAI can effectively optimize the surface morphology of perovskite and improve the surface crystallinity of perovskite,which results in an great improvement of the stability of the device.At the same time,PEAI can effectively improve the short-circuit current and open-circuit voltage of the device,and finally achieve the purpose of improving the performance of the device.This chapter systematically studied the effect of PEAI dissolved in different antisolvents on the performance of perovskite solar cells,and it was found that PEAI dissolved in chlorobenzene had the best performance of solar cells.By analyzing thesurface morphology,crystallinity and hydrophobicity of PEA_xFA_1-xSn I₃（x=0.2,0.3,0.4 or 0）were characterized,it was found that excessive PEA_xFA_1-xSn I₃ could inhibit the device performance.The results show that the device has the best efficiency performance when x=0.2,and the energy conversion efficiency is 3.58%,which is significantly higher than that of the device without PEAI.（3）By adding fluorinated aromatic cation 2-（4-fluorophenyl）ethylammonium iodide（FPEAI）on the hole transport layer,,the interface between the cavity II hole transport layer and the perovskite absorber layer is modified to form FPEA_xFA_（1-x）Sn I₃ structure,which can effectively improvesthe device performance.According to the experimental results,the device performance and surface morphology was achieved when the molar ratio x is 0,0.1,0.2 and 0.3.The experimental results show that the device efficiency increases first and then decreases as the blend rate of FPEAI concentration in isopropanol is increasing.The molar ratio of the device with the highest efficiency is x=0.2,with the short-circuit current increases from 16.56 m A·cm^-2 to 20.06 m A·cm^-2,while the filling factor of the device increases from 52.34%to 60.99%,which increased by nearly 20%.As a results,the device efficiency increased from 3.03% to 4.59%.