Oxygen sensitivity analysis of tin-lead hybrid perovskites solar cells with different ratios

Metal halide perovskites have a wide range of industrial prospects due to their inherent advantages. Narrow bandgap (less than 1.30 eV) tin-lead hybrid perovskite cells as the base cell of all-perovskite stacked solar cells can further improve the photovoltaic conversion efficiency. This cell has many problems, including poor crystal quality and easy oxidation of Sn²⁺. Therefore, the preparation of high quality Sn-Pb hybrid perovskite solar cells is a challenging but interesting research topic. This paper specifically discusses the sensitivity analysis of perovskite films with different tin-lead ratios to oxygen and the photovoltaic performance of the devices. Firstly, the perovskite films with different tin-lead ratios were experimentally prepared, and then the intrinsic differences between the two narrow bandgap tin-lead hybrid perovskite were tested and analysed by XPS, UPS, Raman spectra, etc. The perovskite with the ratio of Sn₆Pb₄ are susceptible to oxidation by airborne oxygen and produce Sn vacancies which further cause severe P-type self-doping, thus seriously affecting the device performance and its stability. whereas Sn₅Pb₅ ratio perovskite shows better stability, and the film exhibits a weak P-type, thus, The 21.59% PCE of Sn₅Pb₅ perovskite solar cells was higher than that of Sn₆Pb₄ perovskite solar cells (19.07 %).