Effects of metal chloride on promoting the emission efficiency and stability of 2D CsPb₂(ClBr)₅ perovskite nanocrystals and their application

Two-dimensional (2D) Cu²⁺–Mn²⁺ co-doped CsPb₂(ClBr)₅ nanocrystals (NCs) with various Cu/Mn molar ratios were synthesized by a simple one-pot method at room temperature. Additionally, we encapsulated C₃H₉SiCl to protect the co-doped CsPb₂(ClBr)₅ NCs from moisture. The analysis of the structure and composition confirmed the phase and chemical composition of the 2D co-doped CsPb₂(ClBr)₅ NCs. Steady-state and time-resolved photoluminescence (PL) spectroscopy revealed the enhanced optical properties of the 2D co-doped CsPb₂(ClBr)₅ NCs. Meanwhile, the optical properties of Cu²⁺–Mn²⁺ co-doped NCs presented the good thermal stability even after 36 days. The photoluminescence quantum yields (PLQYs) related to the Mn²⁺ emission of the 2D co-doped CsPb₂(ClBr)₅ NCs increased to 97.36% at a Cu/Mn molar ratio of 0.05/1. Furthermore, a prototype white light-emitting device (WLED) was successfully assembled by combining orange‒red Cu²⁺–Mn²⁺ co-doped CsPb₂(ClBr)₅ NCs, a CsPbBr₃ film, and a 365 nm commercial UV chip; this prototype confirms its potential for a wide range of applications in general lighting.