Realizing Efficient and Stable n-i-p Perovskite Solar Cells with CuSCN Hole Transporting Materials via LiSCN Doping and Interface Modulation

Inorganic hole transporting materials (HTMs) are the most promising candidates to tackle the troublesome stability issue of conventional perovskite solar cells (PSCs). CuSCN is one of the most efficient inorganic HTMs in the n-i-p structure. However, CuSCN-based PSCs show inferior efficiency compared with other HTMs, greatly limiting their development. The limitation is mainly attributed to two factors: (i) the interface issue caused by the damage of the diethyl sulfide solvent of CuSCN on perovskite; (ii) the inferior conductivity of CuSCN compared with other HTMs such as Spiro-OMeTAD and NiOx. Herein, we proposed an interface modifier by adopting the self-assembled monolayer molecule Me-4PACz, which not only protects perovskite from DES damage but also promotes carrier extraction and transportation. Combined with the LiSCN doping strategy, a high efficiency of 20.95% was achieved for n-i-p PSCs based on CuSCN. More importantly, the unencapsulated device exhibited much-enhanced stability in air compared with the device using Spiro-OMeTAD. Overall, this work demonstrates the potential of CuSCN as an efficient and stable HTM by reasonable doping and modulation strategies.