Mn2+‐Based Hybrid Metal Halides: A‐ and B‐Site Co‐Doped Cs3MnBr5 with High Luminescence and High Temperature Stability via High‐Energy Ball Milling

Abstract Mn 2+ ‐based metal halides are important materials in the study of lead‐free metal halides because of their high luminous efficiency, extensive availability of raw materials, and nontoxicity. At present, the synthesis of Cs₃MnBr₅ is impeded by the presence of intricate processes and environmental pollution, and the formation of crystals exhibits poor stability and low photoluminescence (PL) intensity. In this paper, an Mn 2+ ‐based hybrid metal halide was synthesized by co‐doping Cs 3 MnBr 5 at the A and B sites. This synthesis was conducted under high‐energy ball milling conditions for 25 min, resulting in a material with high photoluminescence intensity and temperature stability. In the new system, a hydrogen bond system and a [MnBr z (H 2 O) 4‐ z ] 2‐ z structure with high‐binding energy are constructed. PL intensity of [Cs 0.85 (C 7 H 17 N 2 ) 0.15 ] 3 Mn 0.8 Mg 0.2 Br 5 · (6H 2 O) 0.2 is 302% of the initial value of Cs 3 MnBr 5 . The high‐temperature thermal stability test of the samples was conducted using a platform constructed in our laboratory. The results demonstrated that the PL intensity after three rounds of thermal cycling is 374% of the initial value of Cs 3 MnBr 5 , which only decreases by 2.9% compared with the maximum. The solid‐phase synthesis of Mn 2+ ‐based hybrid metal halides with excellent high‐temperature luminescence stability has been realized, which shows a potential application prospect in the field of display.