Efficient red-emitting lead-free cesium-scandium halide perovskite crystals produced via Mn2+ doping

Abstract

Perovskite crystals with high photoluminescence quantum yields can be rapidly synthesized by doping Mn2+ into Cs2ScCl5·H2O through a facile wet chemistry approach. The quantum yield of the Mn2+-doped perovskite crystals in the red light region is over 12 times higher than that of the host material and nearly 24 times higher than that of pure Mn-based perovskite CsMnCl3·2H2O. Moreover, density functional theory calculations were used to study the orbital hybridization properties of the materials to further investigate their optical properties. After Mn2+ doping, the Mn octahedrons separated by the Sc octahedrons can more effectively restrict excitons, which is conducive to the improvement of quantum yields. Compared with the original band gap, a new hybridized orbital attributed to Mn and the host element appears. The doped sample shows an extended absorption and excitation range from the original deep-ultraviolet (UV) absorption to UV and visible absorption. Based on these properties, the Mn2+-doped perovskites are used to prepare efficient white light-emitting diodes excited by a blue chip, showing an excellent color rendering index of 91, which meets the need for future applications in the field of optoelectronics.