Spray deposition of exfoliated MoS2 flakes as hole transport layer in perovskite-based photovoltaics

We propose the use of solution-processed molybdenum disulfide (MoS
₂
) flakes as hole transport layer (HTL) for metal-organic perovskite solar cells. MoS
₂
bulk crystals are exfoliated in 2-propanol and deposited on perovskite layers by spray coating. We fabricated cells with glass/FTO/compact-TiO
₂
/mesoporous-TiO
₂
/CH
₃
NH
₃
PbI
₃
/spiro-OMeTAD/Au structure and cells with the same structure but with MoS
₂
flakes as HTL instead of spiro-OMeTAD, the most widely used HTL. The electrical characterization of the cells with MoS
₂
as HTL show promising power conversion efficiency -η- of 3.9% with respect to cells with pristine spiro-OMeTAD (η=3.1%). Endurance test on 800-hour shelf life has shown higher stability for the MoS
₂
-based cells (ΔPCE/PCE=-17%) with respect to the doped spiro-OMeTAD-based one (ΔPCE/PCE =-45%). Further improvements are expected with the optimization of the MoS
₂
deposition process