Science News: 2021 Chem. Eng. J., Novel Sulfonium Salt Interface Passivation toward Efficient and Stable Perovskite

　　Chemical Engineering Journal (IF 13.273) published a study in October 2021. The research team achieved an interface passivation strategy by embedding a new type of sulfonium salt and realized a stable and efficient perovskite solar cell.

　　Due to its excellent photoelectric properties, halide perovskites have been widely used in various optoelectronic devices. Among them, perovskite solar cells have received increasing attention from academia and industry. However, the polycrystalline perovskite film will produce a large number of defects during the rapid crystallization process, which may cause serious carrier recombination, which greatly affects efficiency and stability.

　　In this study, the researchers used the new sulfonium salt (2-carboxyethyl) dimethyl sulfonium chloride (CDSC) and the reference molecule 3-dimethylamino propionic acid hydrochloride (DPAH) to change the perovskite and electron transport layer through the passivation strategy of the buried interface. Researchers also analyzed the photovoltaic characteristics of perovskite solar cells by using the solar simulator and standard cells. Research results showed that these two modifiers could not only passivate the defects on the surface of perovskite and SnO2 films, but also reduced the interface energy barrier by improving the band arrangement. The DPAH and CDSC modified devices achieved PCE of 21.44% and 22.22%, far exceeding 20.72% of the control group. The unpackaged CDSC device still maintained 92.5% of its initial efficiency after aging at 60°C for 1272 hours, which provided a new idea for the use of new materials to passivate the buried interface.