Scalable Modification of an Evaporated Self-Assembled Transport Layer through Evaporated CuSCN

The [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) self-assembled monolayer (SAM) deposited by solution processing has been widely used as an excellent hole-transporting material in high-performance inverted perovskite solar cells (PSCs). While vacuum-based evaporation of Me-4PACz offers significant potential for large-scale PSC fabrication, its application is hindered by the poor wettability of the evaporated SAM, which adversely affects the device performance. In this work, an evaporated cuprous thiocyanate (CuSCN) film was employed to modify the evaporated Me-4PACz, which can improve the wettability, leading to enhanced coverage and uniformity of the perovskite film. In addition, the incorporation of CuSCN established an energy level gradient at the SAM-perovskite interface, facilitating efficient hole transport. Moreover, the CuSCN layer contributed to interface passivation, effectively reducing interface recombination losses. As a result, an efficiency of 21.62% for single-junction wide-bandgap PSCs (1.68 eV) was achieved. Additionally, the films fabricated by evaporation show good uniformity on a large-area substrate, laying a foundation for large-area PSCs.