Efficient inverted CsPbI3 perovskite solar cells fabricated in common air

CsPbI3 perovskite shows great potential for photovoltaic applications due to its excellent photovoltaic performance and thermal stability. However, CsPbI3 perovskite solar cells (PSCs) are extremely sensitive to moisture, and strict humidity control is necessary during its fabrication, limiting their further commercialization. Here, we report the fabrication of efficient CsPbI3 PSCs in common air without humidity control through introducing humidity-assisted polymerizable additive of mercaptopropylme-methyldimethoxysilane (MMDS). During CsPbI3 film formation, MMDS molecules can rapidly react with water in humidity air, and then self-polymerize to a water-resistant polymer at grain boundaries to reduce further moisture invasion. Moreover, -SH group in MMDS can passivate under-coordinated Pb2+ and reduce the trap density in CsPbI3 films. As a result, high efficiency of > 18 % is realized in inverted CsPbI3 PSCs regardless of relative humidity among 40 ∼ 80 %. And the best efficiency reaches 19 %, which is among the highest efficiency of CsPbI3 PSCs in inverted configuration. In addition, stability of MMDS-CsPbI3 PSCs is also greatly improved and 88 % of initial efficiency can be retained after MPP tracking for 1000 h.