An effective Fe() doping strategy for stable and highly photoluminescent CsPbBrI nanocrystals

Doping metal ions into a perovskite lattice is an effective strategy for tailoring the intrinsic properties of perovskite nanocrystals (NCs). Herein, strong red-emitting and highly ambient and light stable Fe 2+ -doped CsPbBrI 2 NCs with a maximum photoluminescence quantum yield (PLQY) of 92.1% were obtained. Systematic investigation of Fe 2+ doping on the stability and the luminescence performance of CsPbBrI 2 NCs was performed. Owing to the smaller ionic size compared to Pb 2+ , Fe 2+ induced the lattice contraction and shortened the bond length of Pb-X, which suppressed the distortion of [PbX 6 ] 4− octahedra, thus improving the stability of CsPbBrI 2 NCs. The champion sample could maintain up to 86% emission under the ambient conditions for 5 weeks. Besides, the incorporation of Fe 2+ suppressed the formation of halide vacancies and optimized the relaxation process of CsPbBrI 2 , thereby contributing to the enhancement of PLQY. This facile Fe 2+ doping method provides an effective strategy to synthesize stable and highly photoluminescent red perovskite materials. Iron dopants (FeBr 2 , FeAc 2 , and FeF 2 ) have been used to modify the performance of red CsPbBrI 2 perovskites, and stable and highly photoluminescent Fe 2+ doped CsPbBrI 2 nanocrystals were obtained.