A Scalable H2O–DMF–DMSO Solvent Synthesis of Highly Luminescent Inorganic Perovskite-Related Cesium Lead Bromides

All-inorganic cesium lead bromide perovskites have attracted a lot of attention because of their excellent optical properties that can potentially be applied in various optical devices. However, large-scale preparation of cesium lead bromide perovskites with outstanding optical performance is still hindered by the poor solubility of CsBr in polar aprotic solvents. In this work, a water/dimethylsulfoxide (DMSO)/dimethylformamide (DMF) system is demonstrated for the synthesis of inorganic cesium lead bromide perovskites, where the introduction of water can effectively address the dissolution issue of Cs + ions. Large-scale synthesis of pure-phase emissive Cs 4 PbBr 6 with a product yield of up to 73% is achieved and the photoluminescence quantum yield of resulting product reaches as high as 76%. The origin of the light emission is further revealed by the photoluminescence evolution of the colored Cs 4 PbBr 6 single crystals. Furthermore, reversible phase transitions between Cs 4 PbBr 6 , CsPbBr 3 and CsPb 2 Br 5 are achieved by changing solely the water content, which paves the way for the recycle of the mother solution of Cs 4 PbBr 6 without generation of additional hazardous waste. The three-solvent-based synthetic approaches enable an economical, robust, and large-scale production for all-inorganic cesium lead bromide perovskites.