Preparation of tin-based perovskite solar cell thin films assisted by stannous fluoride

While the conversion efficiency is constantly refreshing, perovskite solar cells are also actively moving towards the goal of commercial application. However, its structure contains Pb, a toxic substance, which violates the original intention of energy saving and environmental protection of solar cells and hinders the development of its commercialization. The purpose of this paper is to improve the device performance of environment-friendly lead-free tin-based perovskite solar cells. In this paper, SnF2 is firstly precipitated in perovskite solution and used as heterogeneous nucleation point, which helps tin-based perovskite precipitate faster and more uniformly, and then grows into a flat and compact film after annealing. With the increase of x, the lattice shrinkage of perovskite becomes more obvious, and the unit cell size of the film surface becomes larger. When x increases from 0 to 0.5, the energy conversion efficiency of the same batch of devices reaches 1.803% and VOC is 0.3283 V when x=0.5 is used. Low dimensional tin-based perovskite is formed by doping phenylethylamine into FASnI3 structure, and perovskite thin films are prepared by one-step method with different anti-solvent spin coating, which improves the device performance and greatly improves the stability of solar cells.