In situ synthesis of high-efficiency CsPbBr₃/CsPb₂Br₅composite nanocrystals in aqueous solution of microemulsion

Here, we present the microemulsion method using sodium dodecylbenzenesulfonate and hydrofluoric acid for the in situ synthesis of brightly luminescent CsPbBr3/CsPb2Br5 composite nanocrystals (NCs) in aqueous solution. The obtained CsPbBr3/CsPb2Br5 composite NCs exhibit a photoluminescence quantum yield of 77.0% and a full width at half maximum of 16.0 nm. And solid-state back-lighting devices were fabricated by combining CsPbBr3/CsPb2Br5 composite NCs and red-emitting K2SiF6:Mn4+ phosphors with blue light. The as-fabricated device exhibits a wide color gamut of about 95.8% of the Rec. 2020. This work provides a green, low-cost, and in situ water-phase route to synthesize high-quality cesium lead halide NCs for their practical applications in solid-state back-lighting devices.