Atomically Thin-Layered Molybdenum Disulfide (MoS) for Bulk-Heterojunction Solar Cells.

Transition metal dichalcogenides (TMDs) are becoming significant because of their interesting semiconducting and photonic properties. In particular, TMDs such as molybdenum disulfide (MoS), molybdenum diselenide (MoSe), tungsten disulfide (WS), tungsten diselenide (WSe), titanium disulfide (TiS), tantalum sulfide (TaS), and niobium selenide (NbSe) are increasingly attracting attention for their applications in solar cell devices. In this review, we give a brief introduction to TMDs with a focus on MoS; and thereafter, emphasize the role of atomically thin MoS layers in fabricating solar cell devices, including bulk-heterojunction, organic, and perovskites-based solar cells. Layered MoS has been used as the hole-transport layer (HTL), electron-transport layer (ETL), interfacial layer, and protective layer in fabricating heterojunction solar cells. The trilayer graphene/MoS/n-Si solar cell devices exhibit a power-conversion efficiency of 11.1%. The effects of plasma and chemical doping on the photovoltaic performance of MoS solar cells have been analyzed. After doping and electrical gating, a power-conversion efficiency (PCE) of 9.03% has been observed for the MoS/h-BN/GaAs heterostructure solar cells. The MoS-containing perovskites-based solar cells show a PCE as high as 13.3%. The PCE of MoS-based organic solar cells exceeds 8.40%. The stability of MoS solar cells measured under ambient conditions and light illumination has been discussed. The MoS-based materials show a great potential for solar cell devices along with high PCE; however, in this connection, their long-term environmental stability is also of equal importance for commercial applications.