Shining Mn4+ in 0D Organometallic Fluoride Hosts towards Highly Efficient Photoluminescence

Abstract

AbstractThe design and discovery of Mn4+‐activated fluoride phosphors that can secure both high luminescence efficiency and short fluorescence lifetime simultaneously are crucial and urgent for constructing high‐quality wide‐color gamut (WCG) backlight display applications. Herein, a series of brand‐new Mn4+‐activated narrow‐band red‐emitting phosphors with both high external quantum efficiency (EQE, >50%) and short fluorescence lifetime (τ ≤ 3.8 ms) are designed by introducing Mn4+ into newfound tetramethylammonium (Me4N)‐based organometallic fluoride (Me4N)2BF6 (B = Ge, Ti, Zr) hosts. These intriguing properties of Mn4+ arise from the larger steric hindrance of (Me4N)+ cations and low local structure symmetry in the 0D (Me4N)2BF6, as verified by the structural and spectral analyses. (Me4N)2GeF6:Mn4+, as a representative, shows a high EQE of ≈64.6% and a short lifetime of ≈3.78 ms. A prototype projector with superb performance is assembled by employing a remote (Me4N)2GeF6:Mn4+‐based white light‐emitting diode with high luminous efficiency (≈143.09 lm W−1) and WCG (≈112.02% National Television System Committee (NTSC)) to demonstrate their great potentials for backlight applications. The research brings up a promising alternative as the host materials for Mn4+‐doped fluoride phosphors and provides a deeper understanding on the correlation between structure and luminescence.