Regulating the Optical Properties of Cs3MnBr5 Nanocrystals in Glasses for Narrow-Band Green Emission

Environmentally friendly phosphors with narrow-band green luminescence are in great demand for solid-state lighting and backlight display applications. Herein, all inorganic lead-free Cs3MnBr5 nanocrystals (NCs) are prepared in glass with dual-band luminescence and a high photoluminescence (PL) quantum yield of 60.2%. However, due to the short separation and strong coupling interaction between neighboring [MnBr4]2− units, Cs3MnBr5 NCs undergo energy transfer from a single [MnBr4]2− unit to coupled [MnBr4]2− clusters and give green-red dual-band PL. Incorporation of Zn into Cs3MnBr5 NCs therefore enlarges the average separation and reduces the interaction between neighboring [MnBr4]2− units to inhibit energy transfer from the green-emitting [MnBr4]2− unit to coupled [MnBr4]2− clusters, thus changing the dual-band PL into single-band green PL at 524 nm with a full width at half maximum of 47 nm and a maximal PL quantum yield of 50%. Low-temperature PL also demonstrates that partial replacement of Mn2+ ions by Zn2+ ions can further confine the exciton in the [MnBr4]2− unit and suppress the energy transfer. These Cs3MnBr5 NCs- and Zn/Cs3MnBr5 NCs-embedded glasses also possess good thermal, photo-, and chemical stabilities. These features demonstrate that these Cs3MnBr5 NCs- and Zn/Cs3MnBr5 NCs-embedded glasses have potential applications for efficient, environmental-friendly, and stable green phosphors in the fields of solid-state lighting and backlight display.