Synergy of ammonium chloride and moisture on perovskite crystallization for efficient printable mesoscopic solar cells

Abstract

Abstract Organometal lead halide perovskites have been widely used as the light harvester for high-performance solar cells. However, typical perovskites of methylammonium lead halides (CH 3 NH 3 PbX 3 , 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 TiO 2 /ZrO 2 /Carbon to fabricate printable mesoscopic solar cells. An additive of ammonium chloride (NH 4 Cl) is employed to assist the crystallization of perovskite, wherein the formation and transition of intermediate CH 3 NH 3 X·NH 4 PbX 3 (H 2 O) 2 (X=I or Cl) enables high-quality perovskite CH 3 NH 3 PbI 3 crystals with preferential growth orientation. Correspondingly, the intrinsic perovskite devices based on CH 3 NH 3 PbI 3 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.