Boosting Stability of Hybrid Manganese Bromide Microcrystals by Zn²⁺ Substitution for Wide-Gamut Displays

Hybrid manganese bromides have emerged as promising lead-free narrow-band green emitters for wide-gamut displays, but their practical application is still limited by insufficient operational stability. Herein, Zn²⁺ substitution is employed to enhance the stability of tetraethylammonium manganese bromide (TEA₂MnBr₄) microcrystals (MCs) synthesized via an ultrafast self-assembly method. With increasing Zn²⁺ contents, the photoluminescence intensity of TEA₂Mn_1-xZn_xBr₄ MCs gradually decreases, while the x = 0.10 MCs still exhibit efficient narrow-band green emission at 518 nm and a high photoluminescence efficiency of about 85% under blue excitation. More importantly, Zn²⁺ incorporation substantially enhances the storage and thermal stability, as well as operational stability of the corresponding green LED devices (retaining above 99% of initial luminous efficacy after 160 h continuous operation at 20 mA). Finally, a white LED fabricated using the x = 0.10 MCs achieves a high luminous efficiency of about 136 lm/W and covers about 112% of the National Television System Committee 1931 color gamut. These results demonstrate that Zn²⁺ substitution is an effective strategy for stabilizing hybrid manganese bromide emitters and highlight their potential for lead-free wide-gamut display applications.