Fabrication of stable and efficient 2D/3D perovskite solar cells through post-treatment with TBABF

Perovskite solar cells (PSCs), with their low cost and simple fabrication, have emerged as promising devices to solve global warming issues. In this study, tetrabutylammonium tetrafluoroborate (TBABF 4 ) was used as a passivator to boost the performance and the stability of the fabricated PSCs. Through TBABF 4 post-treatment, the perovskite film's grain boundaries were passivated, which caused a reduction of charge traps on the surface of the perovskite layer and served as interfacial engineering at the perovskite/hole transport layer (HTL) interface. It was found that TBABF 4 can act as a source of TBA + cations and cause the formation of a 2D/3D heterostructure layer, which increases the stability of PSCs. Indeed, the 2D/3D structure derived from TBABF 4 solution plays the role of a shield layer to protect the surface of the perovskite layer from degradation and facilitates charge transport processes. The post-treatment of perovskite films is, thus, introduced as an approach to address both the stability and the performance of PSCs and as a step forward to commercialize PSCs. A promising 2D/3D heterostructure based on TBABF 4 salt to boost the performance and stability of perovskite solar cells.