Science News: 2022 Nature (IF 49.962), Poor Stability of PSC again? This Team Found the Side Effect of Surface Passivation

　　Optoelectronic devices contain many semiconductor materials, and heterogeneous interfaces are formed between different materials. The relative energy level matching results between semiconductor materials will affect the heterointerface charge injection and extraction dynamics. Taking perovskite solar cells (PSCs) as an example, scholars usually target the heterointerface between the top perovskite surface and the charge transport material (CTM) for defect passivation to improve the stability and performance of PSCs. But this surface treatment may also affect the energetics of the heterointerface.

　　Nature (IF 49.962) published a study in March 2022. The research team here found that surface treatments may induce a negative work function shift (i.e., more n-type) and generate halide migration that exacerbates PSC instability. Using a material composed of (FAPbI₃)_0.95(MAPbBr₃)_0.05, they investigated the effect of the energy of the perovskite surface, including the energy of the heterointerface on carrier extraction, trap passivation, charge accumulation, and ion migration. The experimental results show that although surface passivation helps, the side effects of surface passivation limit the development of PSC stability. In the future, if you want to improve the stability of PSC through surface treatment, the trade-off between the beneficial and detrimental effects should be considered.