A Novel Red-Emitting Na(2)NbOF(5):Mn(4+) Phosphor with Ultrahigh Color Purity for Warm White Lighting and Wide-Gamut Backlight Displays

In this work, a novel red-emitting oxyfluoride phosphor Na(2)NbOF(5):Mn(4+) with an ultra-intense zero-phonon line (ZPL) was successfully synthesized by hydrothermal method. The phase composition and luminescent properties of Na(2)NbOF(5):Mn(4+) 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, Na(2)NbOF(5):Mn(4+) exhibits red light emission dominated by ZPL. Notably, the color purity of the Na(2)NbOF(5):Mn(4+) red phosphor can reach 99.9%. Meanwhile, the Na(2)NbOF(5):Mn(4+) phosphor has a shorter fluorescence decay time than commercial K(2)SiF(6):Mn(4+), 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(c) = 3133 K is realized using yellow YAG:Ce(3+) and red Na(2)NbOF(5):Mn(4+) phosphor. The WLED fabricated using CsPbBr(3) quantum dots (QDs) and red Na(2)NbOF(5):Mn(4+) phosphor shows a wide color gamut of 127.56% NTSC (National Television Standard Committee). The results show that red-emitting Na(2)NbOF(5):Mn(4+) phosphor has potential application prospects in WLED lighting and display backlight.