Achieving 57.15% EQE in Mn4+ Non-equivalent Doped Fluoride Single Crystals via a Rapid Synthesis for Next-Generation Display Lighting

Abstract

Mn4+ non-equivalent doped fluorides with long-wavelength and narrow-spectrum emission ensure ultrawide-gamut display applications. However, the existing synthesis schemes result in the suboptimal quantum efficiency of non-equivalent doped materials. This study develops a group-substituted single crystal (GSC) method assisted by pre-nucleation strategy to achieve the growth of high-quality K2LiGaF6:Mn4+ single crystals with optimal photoluminescence performance and chemical stability. To avoid the adverse effects caused by the long reaction time of Mn4+, the GSC method achieves rapid preparation of K2LiGaF6:Mn4+ single crystals within 12 hours, which is 90% shorter than typical methods and beneficial in preventing the degradation of Mn4+. As a result, it not only achieves a high external quantum efficiency of 57.15% but also exhibits excellent stability. A white light-emitting diode (LED) fabricates using blue light chip, commercial green phosphor (β-Sialon:Eu2+) and the optimized KLGFM-GSC crystal can achieve an ultrawide color gamut display of 109.3% National Television Standards Committee (NTSC). In summary, the method of synthesizing single crystals with GSC has good universality, opening a new way for the preparation of high-quality Mn4+ non-equivalent doped fluoride single crystals and promoting the development of ultrawide color gamut display applications.