Highly Ambient Stable CsSnBr3 Perovskite via a New Facile Room-Temperature "Coprecipitation" Strategy

Tin-based perovskites are becoming promising alternativesto lead-basedperovskites with eco-friendly merit and tantalizing photophysicalproperties. Unfortunately, the lack of facile, low-cost synthesisapproaches associated with extremely poor stability greatly restricttheir practical applications. Herein, a facile room-temperature "coprecipitation"method utilizing ethanol (EtOH) solvent and salicylic acid (SA) additiveis proposed for synthesizing highly stable cubic phase CsSnBr3 perovskite. Experimental results show that ethanol solventand SA additive can not only effectively prevent the oxidation ofSn(2+) during the synthesis processes but also stabilizethe as-synthesized CsSnBr3 perovskite. These are mainlyascribed to the protection effect of ethanol and SA, which are attachedon the surface of CsSnBr3 perovskite by coordinating withBr(-) and Sn2+ ions, respectively. As aresult, CsSnBr3 perovskite can be obtained in open airand exhibits exceptional oxygen resistibility under moist air conditions(temperature: 24.2-25.8 degrees C; relative humidity: 63-78%).Absorption remains unchanged and photoluminescence (PL) intensityis vastly maintained (similar to 69%) after storage for 10 days, betterthan bulk CsSnBr3 perovskite film synthesized by spin-coatingmethod whose PL intensity is decreased to 43% after storage for 12h. This work represents a step toward stable tin-based perovskiteby a facile and low-cost strategy.