Study Of Perovskite Solar Cells Based On High-molecular Polymer Blending

Perovskite solar cells not only has many advantages of organic polymer solar cells, but also has their large exciton diffusion distance and low exciton binding energy, the perovskite solar cells has received the widespread attention. Although perovskite solar cells have excellent performance, and light absorption layer material has the characteristics of low cost and the solution process, but the perovskite solar cells still exist many problems, such as low reproducibility of high performance of device, poor stability, roughness of the perovskite film, poor contact interface, and large area of perovskite film manufacting. At present many groups made a lot of work on the interface modification, heat treatment, solvent selection, additives and structure design, in order to get better performance and stability perovskite solar cells.This thesis is mainly focus on the study of high quality perovskite film and the device performance. On the base of explaining the background and the development history of the polymer solar cells, the necessity of its study is analysised. To better understand the perovskite solar cell device, its complete preparation process and testing process are been expounded, and its main performance parameters are also been analyzed.The quality of the perovskite surface morphology is crucial for the performance of the perovskite solar cell device. In this paper, adding three kinds of polymer into the perovskiter precursor solution, testing the film XRD, uv-vis absorption spectrum and SEM, found that adding PVP and PAN can improve the quality of perovskite film. On this basis, through adding three kinds of polymer into the perovskite precursor solution to manufact perovskite solar cells, the devices were characterized and optimized, open circuit voltage, short circuit current and the fill factor of the device got obvious improvement. When adding PVP into the perovskite precursor solution, the photoelectric conversion efficiency of the device increases from 2.83% to 6.7%.For the preparation of high efficient perovskite solar cells, usually methods mainly include one-step solution spin coating, two-step solution, co-evaporation and vapor-assisted solution process. In this article, another method is used to preparation of perovskite films, through evaporation method for the preparation of Pb I₂ films, then spin CH₃NH₃ I solution, both reaction for the preparation of the perovskite film, exploring its effect on the properties of perovskite solar cell device. At the time of deposition PbI₂, evaporate respectively 50 nm, 100 nm and 100 nm thick Pb I₂ films, we found that evaporating of 100 nm thick Pb I₂ films and spining concentration of 30mgml^-1 CH₃NH₃ I isopropyl alcohol solution preparation of perovskite films, the device performance is better, getting a 6.09% of the photoelectric conversion efficiency. We combined with XRD spectrum test and the analysis of the device performance, and discussed the influence of PbI₂ thickness on device performance.The ionic radius of Eu²⁺ is 0.117, in the CH₃NH₃PbI₃ structure, the ionic radius of Pb2+ is 0.119, so we try to use Eu²⁺ replacing part of the Pb2+ in the perovskite structure, and study doping Eu²⁺ for the effect of device performance. Adding different proportion Eu I₂ in the PbI₂, use a two-step solution to preparation of perovskite solar cells. The devices were characterized, the open circuit voltage of the device have been a certain degree of increase after doping Eu²⁺, but the short circuit current and fill factor decrease. The series resistance is calculated, found the series resistance of the device is only has 7.2Ω·cm² without doping, series resistance of the device increase after doping Eu²⁺, when adding 5mgml^-1EuI₂, the series resistance up to 66.6Ω·cm².