Optimization Of P-type Interface In The Top Cell Of All-texture Perovskite/Crystalline Tandem Silicon Solar Cells

Both the crystalline silicon cells dominated by the photovoltaic market and the hot perovskite solar cells have reached very high photoelectric conversion efficiency,which is closer to the limit of the Shockley-Queisser theory.However,in order to meet people’s pursuit of higher efficiency and promote the further development of photovoltaic technology,the tandem solar cell have gradually become the focus of research.By connecting sub-cells with different band gaps in series,the maximum utilization and absorption of sunlight can be achieved,and the theoretical maximum efficiency is more than 40%.Because of its low band gap and perfect production process,crystalline silicon cells have excellent conditions as bottom cells,which is just complementary with low-cost perovskite solar cells with adjustable band gap to achieve higher photoelectric conversion efficiency.However,the most studied perovskite solar cells are prepared by solution method at present,but the marketable crystalline silicon cells have a suave structure,so it is difficult for perovskite prepared by solution method to uniformly cover the surface of crystalline silicon cells,which is a challenge for perovskite /silicon tandem solar cell.The vacuum assisted two-step perovskite process is to steam a layer of inorganic film mixed with lead iodide and cesium bromide through vapor deposition,and then spin coating with organic amine salt to form a relatively uniform perovskite layer through annealing.This method perfectly solves the problem of uniform covering of perovskite on the velvet surface and can meet the needs of large-scale production.However,the vapor deposition in the first step of the vacuum assisted two-step method is vaporized by thermal evaporation equipment,so it is difficult to avoid the accumulation and projection of some particles on the suede,so the obtained perovskite film still has many defects at the perovskite interface,especially the lower interface of perovskite(p-type interface)non-radiation composite loss is large.We first optimized the vacuum assisted two-step process in a single perovskite battery,determined the thickness of the inorganic layer in the first step and the concentration of the organic amine in the second step,and then introduced the defects at the passivation interface of the two dimensional perovskite passivation layer into the p-type interface of perovskite,and improved the crystallization of the upper perovskite to make the grain larger.After passivation,the device open-circuit voltage and fill factor are significantly improved.Finally,the passivation strategy was applied to perovskite /silicon tandem solar cell,and the same effect was obtained.After passivation,the grain of perovskite was full,and the uniform covering of perovskite on the suvete was not affected.In terms of device performance,the short-circuit current density of the laminate cell decreased slightly,which may be related to the transverse conductive shunt of two-dimensional perovskite,but it performed well in terms of open-circuit voltage and filling factor.The results showed that after the optimization of perovskite process and the introduction of two-dimensional perovskite passivation layer,the open-circuit voltage of the perovskite /silicon tandem solar cell reached 1.83 V.The filling factor was 76.69 % and the optimal PCE was28.59 %.