B-Site Doping Engineering of Zero-Dimensional Perovskite Cs3MnCl5: Stability Improvement and Multicolor Luminescence Regulation

Abstract

Mn-based zero-dimensional metal halide perovskites have attracted much attention in  the  field  of  lead-free  optical  materials due to their rich manganese reserves,  environmental  friendliness,  and  the  unique  d–d  transition characteristics of Mn²⁺. However, the poor water and  oxygen  stability  and  single  luminous color  of  the  intrinsic  material  severely  limit  the practical applications. In this paper, high-quality all-inorganic zero-dimensional perovskite Cs₃MnCl₅ single crystals were successfully prepared by the vacuum solid-state reaction method, and the regulation mechanism of heterovalent ions (Ag⁺, Ce³⁺, Sb³⁺) on the stability and luminescence properties of the materials was studied by B-site doping. X-ray diffraction and X-ray photoelectron spectroscopy analysis confirm that the doped ions successfully enter the Cs₃MnCl₅ lattice and occupy the Mn²⁺ sites, resulting in lattice expansion. Optical characterization shows that the intrinsic Cs₃MnCl₅ exhibits a bright green emission at 520 nm derived from the  ⁴T₁–⁶A₁  transition  of  the  Mn²⁺  tetrahedral coordination. Ag⁺ doping significantly improves the environmental stability of the material, and the maintenance time of green fluorescence in a high-humidity environment increases by more than ten times compared with the intrinsic material. Ce³⁺ doping induces the dual luminescence of violet (≈ 420 nm) derived from the Ce³⁺ 5d–4f transition and green emission from Mn²⁺, and the dual intensity ratio can be flexibly adjusted by excitation wavelength to achieve cold white light emission at 365 nm excitation. Sb³⁺ doping introduces orange emission (≈ 585 nm), derived from the Sb^{3+ 3}P₁–¹S₀ transition, resulting in yellow–green fluorescence. This work provides a new design idea for the application of Mn-based zero-dimensional halides.