Solution-grown millimeter-scale Mn-doped CsPbBr 3 /Cs 4 PbBr 6 crystals with enhanced photoluminescence and stability for light-emitting applications.

Metal halide perovskites are particularly emerging for optoelectronic applications in light-emitting diodes, photodetectors, and solar cells due to their flourishing photophysical properties. However, the poor stability of three-dimensional (3D) lead halide perovskite nanocrystals (NCs) significantly hampers their optoelectronics and photovoltaics applications. Embedding 3D perovskites into zero-dimensional (0D) perovskite crystals and doping ions of appropriate elements into host lattices provide effective approaches to improve the stability and optical-electronic performance. In this study, millimeter-scale Mn-doped and undoped CsPbBr ₃ /Cs ₄ PbBr ₆ perovskite crystals were successfully fabricated by a one-step slow cooling method. We systematically investigated the effects of Mn ²⁺ ion doping on the PL performance and stability of CsPbBr ₃ /Cs ₄ PbBr ₆ crystals. Compared with undoped crystals, the existence of Mn ²⁺ ions not only blue-shifted the PL peak but also improved the luminescence performance and stability of the prepared millimeter-sized crystals. Moreover, doping Mn ²⁺ ions can increase the proportion of radiative recombination at low temperature, which may be because Mn ²⁺ ions can effectively accelerate the decay of a dark exciton by the magnetic mixing of bright and dark excitons. In addition, green LED devices with high efficiency packaged as-grown crystals are explored, which promises further application in display backlights.