One-Pot Synthesis of Stable CsPbBr 3 @CsPb 2 Br 5 Core–Shell Heteronanocrystals with Controlled Permeability to Halide Ions

A simple one-pot synthetic strategy based on the hot injection methodology was adapted to prepare (photo)stable and green emissive colloidal CsPbBr 3 @CsPb 2 Br 5 core@shell heteronanocrystals (HNCs). The photoactive core, specifically CsPbBr 3 ternary metal halide nanocrystals, was homogeneously covered with an ultrathin CsPb 2 Br 5 shell (ca. 2 nm), which confers them with long-term stability and a higher photoluminescence quantum yield. Astonishingly, this heterostructure enabled controlled halide exchange to yield unprecedented CsPbCl 3 @CsPb 2 Cl 5 and CsPbI 3 @CsPb 2 I 5 HNCs.