A Novel Red-Emitting NaNbOF:Mn Phosphor with Ultrahigh Color Purity for Warm White Lighting and Wide-Gamut Backlight Displays.

In this work, a novel red-emitting oxyfluoride phosphor NaNbOF:Mn with an ultra-intense zero-phonon line (ZPL) was successfully synthesized by hydrothermal method. The phase composition and luminescent properties of NaNbOF:Mn were studied in detail. The photoluminescence excitation spectrum contains two intense excitation bands centered at 369 and 470 nm, which match well with commercial UV and blue light-emitting diode (LED) chips. When excited by 470 nm blue light, NaNbOF:Mn exhibits red light emission dominated by ZPL. Notably, the color purity of the NaNbOF:Mn red phosphor can reach 99.9%. Meanwhile, the NaNbOF:Mn phosphor has a shorter fluorescence decay time than commercial KSiF:Mn, which is conducive to fast switching of images in display applications. Profiting from the intense ZPL, white light-emitting diode (WLED) with high color rendering index of Ra = 86.2 and low correlated color temperature of T = 3133 K is realized using yellow YAG:Ce and red NaNbOF:Mn phosphor. The WLED fabricated using CsPbBr quantum dots (QDs) and red NaNbOF:Mn phosphor shows a wide color gamut of 127.56% NTSC (National Television Standard Committee). The results show that red-emitting NaNbOF:Mn phosphor has potential application prospects in WLED lighting and display backlight.