Organometal lead halide perovskites have been widely used as the light harvester for high-performance solar cells. However, typical perovskites of methylammonium lead halides (CH₃NH₃PbX₃, X=Cl, Br, I) are usually sensitive to moisture in ambient air, and thus require an inert atmosphere to process. Here we demonstrate a moisture-induced transformation of perovskite crystals in a triple-layer scaffold of TiO₂/ZrO₂/Carbon to fabricate printable mesoscopic solar cells. An additive of ammonium chloride (NH₄Cl) is employed to assist the crystallization of perovskite, wherein the formation and transition of intermediate CH₃NH₃X·NH₄PbX₃(H₂O)₃ (X=I or Cl) enables high-quality perovskite CH₃NH₃PbI₃ crystals with preferential growth orientation. Correspondingly, the intrinsic perovskite devices based on CH₃NH₃PbI₃ achieve an efficiency of 15.6% and a lifetime of over 130 days in ambient condition with 30% relative humidity. This ambient-processed printable perovskite solar cell provides a promising prospect for mass production, and will promote the development of perovskite-based photovoltaics.

Nature Communications 8, Article number: 14555 (2017)
doi:10.1038/ncomms14555

http://www.nature.com/articles/ncomms14555