Efficient inverted CsPbI3 perovskite solar cells fabricated in common air

CsPbI 3 perovskite shows great potential for photovoltaic applications due to its excellent photovoltaic performance and thermal stability. However, CsPbI 3 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 CsPbI 3 PSCs in common air without humidity control through introducing humidity-assisted polymerizable additive of mercaptopropylme-methyldimethoxysilane (MMDS). During CsPbI 3 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 Pb 2+ and reduce the trap density in CsPbI 3 films. As a result, high efficiency of > 18 % is realized in inverted CsPbI 3 PSCs regardless of relative humidity among 40 ∼ 80 %. And the best efficiency reaches 19 %, which is among the highest efficiency of CsPbI 3 PSCs in inverted configuration. In addition, stability of MMDS-CsPbI 3 PSCs is also greatly improved and 88 % of initial efficiency can be retained after MPP tracking for 1000 h.