High Green Purity and Narrow Emission Ceramic‐Like Perovskite Nanocrystals Enabled by Solid‐Phase Reaction Process

Abstract Here, ceramic‐like CsPbBr₃@SiO₂ nanocrystals (NCs) with a high photoluminescence quantum yield of 98.7%, green purity of 90%, and narrow full width at half maximum of 22 nm are successfully achieved by a solid‐phase reaction process. The SiO₂ shell covers the surface of the NCs, providing long‐term working and excellent thermal cycling stability. Ba²⁺ dopes the lattice of the perovskite structure under high‐temperature sintering at 700 °C, resulting in the red‐shift of the NCs emission due to the decrease of the bandgap caused by the lattice modulation with Ba²⁺. At the same time, the halogen vacancies are effectively passivated by a halogen‐rich environment of dopants (BaBr₂). The Commission Internationale de l'Eclairage of the doped ceramic‐like NCs is (0.170, 0.760), which approaches the Rec.2020 standard. By means of this solid reaction process, red, green, and blue ceramic‐like perovskite NCs are prepared to achieve white light‐emitting diodes, covering 124% of the National Television Standards Committee.