Analysis of the growth mechanism of tin-lead hybrid chalcogenide solar cells with different ratios

Metal halide chalcogenide because of its inherent advantages, chalcogenide solar cells have been rapidly developed in recent years, all-chalcogenide stacked cells can further improve the photoelectric conversion efficiency. Narrow bandgap Sn-Pb hybrid chalcogenide cells are suitable as the bottom cell of stacked cells. Such cells suffer from poor crystal quality and easy oxidation of Sn, all of which lead to low photoelectric conversion efficiency of the cells. Therefore, the preparation of high quality Sn-Pb hybrid chalcogenide solar cells is a challenging but interesting research topic. Based on the above problems, this paper experimentally prepared chalcogenide films with different tin-lead ratios, and then tested and analysed the intrinsic differences between two narrow bandgap tin-lead chalcogenides by SEM, AFM, XRD and other testing means, the chalcogenide with Sn₆Pb₄ ratio is prone to crystalline imbalance problem. the morphology of the tin-lead mixed chalcogenides films with Sn₆Pb₄ ratio is difficult to be controlled and the crystalline property is worse at the same time. The morphology of Sn₆Pb₄ ratio tin-lead mixed chalcocite film is difficult to control and the crystallinity is poor while at the same time the morphology is not good, the chalcocite is prone to form defects and vacancies in the inner part or at the interface. The Sn₅Pb₅ ratio of chalcocite shows better film quality, so that the PCE of Sn₅Pb₅ ratio of chalcocite solar cell is 21.56% which is better than that of Sn₆Pb₄ ratio of chalcocite solar cell which is 19.17%.