A high-efficiency near-ultraviolet excited Mn2+ doped narrow-band emission phosphor via a strong charge transfer for wide color gamut WLED

The research of narrow band green emitter with excellent luminescent property is regarded as a very significant innovation direction for light-emitting diodes (LED) backlights in liquid crystal displays (LCDs). Herein, a high-efficiency near-ultraviolet (n-UV) excitation Mn2+ doped green phosphor NaGa11O17: Mn2+ phosphor is obtained based on the strong charge transfer absorption located in the n-UV region. The optimal sample exhibits a high color purity green light emission(≈89.7%) centered at 505 nm with a full width at half maximum (FWHM) around 29 nm. The absorption efficiency (AE), internal quantum efficiency (IQE) and external quantum efficiency (EQE) of optimal sample are 69.8%, 80.4% and 56.1%, respectively. In addition, the doping of Al3+ significantly improves the thermal stability (26.9%–80.1% at 150 °C) by enhancing the electron recombination process. Using NGO: Mn2+ and commercial β-sialon:Eu2+ dual green phosphors as green component fabricated with BAM: Eu2+, KSF: Mn4+ and 310 nm LED chips shows a wide color gamut of 125% NTSC. These findings suggest that our material may find use in LED backlights for liquid crystal displays and provide a meaningful reference for the development of new narrowband emitters.