In this review article, Mn applications have been divided into three parts. We provide an overview of recent progress in developing Mn⁴⁺ doped red phosphors for promising application in warm white light-emitting diodes. In addition, we summarize reports on Mn²⁺ co-doped Eu²⁺ or Ce³⁺ phosphors that can produce white light with outstanding color rendering index (CRI) and color coordinates via energy transfer processes, and report the application of Mn²⁺ in green to NIR phosphors.

Low-dimensional lead-free metal halide perovskites are highly attractive for cutting-edge optoelectronic applications. Herein, we report a class of scandium-based double perovskite crystals comprising antimony dopants that can generate multiexcitonic emissions in the ultraviolet, blue, and yellow spectral regions. Owing to the zero-dimensional nature of the crystal lattice that minimizes energy crosstalk, different excitonic states in the crystals can be selectively excited by ultraviolet light, X-ray irradiation, and mechanical action, enabling dynamic control of steady/transient-state spectral features by modulating the excitation modes. Remarkably, the transparent crystal exhibits highly efficient white photoluminescence (quantum yield >97%), X-ray excited blue emission with long afterglow (duration >9 h), and high-brightness self-reproducible violet-blue mechanoluminescence. These findings reveal the exceptional capability of low-dimensional perovskite crystals for integrating various excitonic luminescence, offering exciting opportunities for multi-level data encryption and all-in-one authentication technologies.