Carboxylated carbon nanotubes as efficient additive to enhance the performance of different types of perovskite solar cells

Low-temperature processed perovskite films tend to form sub-micrometer scale grains and defects, reducing the performance of perovskite solar cells (PSCs). Additive engineering is an effective way to solve this problem. In the present work, carboxylated carbon nanotubes (COOH-CNTs) were proved to be efficient additive for different types of PSCs. Our study found that COOH-CNTs could improve the performance of PSCs from many aspects: promoting perovskite film crystallization, increasing light harvesting, and enhancing carrier extraction/ transportation. Its effect and mechanism of COOH-CNTs were also detailedly studied. The champion efficiency of (FAPbI3)0.97(MAPbBr3)0.03 PSC improved from 17.27 to 18.91%, and the efficiency of CsPbBr3 and MAPbBr3 devices increased by more than 11% and 7%, respectively.