Highly efficient and stable Cs₃Mn_0.93Zn_0.07Br₅@SiO₂ for wide color gamut backlight displays

Mn-based perovskites have become a new candidate material for backlight display applications. However, low efficiency and poor stability are the key problems limiting the application of Mn-based perovskites. In this work, Zn-doped and SiO₂-encapsulated Cs₃MnBr₅, denoted as Cs₃Mn_0.93Zn_0.07Br₅@SiO₂ (CMZBS), was successfully synthesized to improve the photoluminescence quantum yield (PLQY) and stability. After Zn doping, the PLQY increased from 51% to 72% due to the reduction in the energy transfer between [MnBr₄]^2-. The PLQY can be further improved to 80% after coating SiO₂. Compared with Cs₃MnBr₅ (CMB), CMZBS showed better stability against thermal, air, light, and polar solvents (ethanol and isopropanol). In addition, a white LED (WLED) device with a CIE of (0.323, 0.325) was fabricated by integrating CMZBS and the red phosphor K₂SiF₆:Mn⁴⁺ on a 465 nm blue GaN chip, which exhibited a high luminous efficiency of 92 lm W^-1 and excellent stability, demonstrating its great potential application in wide color gamut displays.