Dual-functional metal (IIB) diethyldithocarbamate salts passivation enabled high-efficiency and stable carbon-based CsPbIBr2 all-inorganic perovskite solar cells

Solution-prepared perovskite films are accompanied by high defect density . Defects gathered on the surface or grain boundaries of the perovskite accelerate the degradation of the perovskite and affect the photovoltaic performance and long-term stability of the device, which is one of the bottlenecks to curb the further development of perovskite solar cells (PSCs). In this work, a simple and effective surface passivation method is designed by choosing metal (IIB) diethyldithiocarbamate salts [M(DDTC) 2 , M = Pb 2+ , Cd 2+ and Zn 2+ ]. The DDTC has excellent complexing ability with metal ions and chelate bidentately with unpaired Pb 2+ ions on the surface of perovskite. IIB metal ions have a small ion radius and could easily diffuse into the perovskite to occupy Pb vacancies. The synergistic effect of anions and cations effectively reduces the defect concentration and non-radiative recombination in the CsPbIBr 2 all-inorganic perovskite, thereby obtaining carbon-based CsPbIBr 2 all-inorganic PSCs with high efficiency and high stability. Ultimately, champion efficiency of the Cd(DDTC) 2 and Zn(DDTC) 2 -treated CsPbIBr 2 PSCs yield 9.59% and 10.21%, respectively, obviously higher than that of the pristine one (8.74%).