A Novel Red-Emitting Na2NbOF5:Mn4+ Phosphor with Ultrahigh Color Purity for Warm White Lighting and Wide-Gamut Backlight Displays

Abstract

In this work, a novel red-emitting oxyfluoride phosphor Na2NbOF5:Mn4+ with an ultra-intense zero-phonon line (ZPL) was successfully synthesized by hydrothermal method. The phase composition and luminescent properties of Na2NbOF5:Mn4+ 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, Na2NbOF5:Mn4+ exhibits red light emission dominated by ZPL. Notably, the color purity of the Na2NbOF5:Mn4+ red phosphor can reach 99.9%. Meanwhile, the Na2NbOF5:Mn4+ phosphor has a shorter fluorescence decay time than commercial K2SiF6:Mn4+, 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 Tc = 3133 K is realized using yellow YAG:Ce3+ and red Na2NbOF5:Mn4+ phosphor. The WLED fabricated using CsPbBr3 quantum dots (QDs) and red Na2NbOF5:Mn4+ phosphor shows a wide color gamut of 127.56% NTSC (National Television Standard Committee). The results show that red-emitting Na2NbOF5:Mn4+ phosphor has potential application prospects in WLED lighting and display backlight.

Crystal Structure, Characterization, and Luminescence Properties of Mn4+‐Doped K3Nb2O4F5

“…[4] This similarity has been suggested to be due to the formation of [MnF 6 ] 2À octahedra as charge compensation in oxyfluoride hosts. [7] Some recent examples for oxyfluoride phosphors are Na 2 NbOF 5 : Mn 4 + , [8] Cs 2 NbOF 5 : Mn 4 + , [9] K 3 WO 2 F 5 • 2 H 2 O : Mn 4 + , [10] K 3 TaOF 6 : Mn 4 + , [11] Cs 3 V 2 O 2 F 7 : Mn 4 + , [12] Cs 30 (Nb 2 O 2 F 9 ) 9 (OH) 3 • H 2 O : Mn 4 + , [13] K 3 (NbOF 5 )(HF 2 ) : Mn 4 + , [14] K 2 SnOF 4 : Mn 4 + , [15] and CsMoO 2 F 3 : Mn 4 + . [16] In some cases, the luminescence spectra of Mn 4 + -doped oxyfluoride phosphors can be blue-shifted even further, with maximum emission wavelengths as low as 627 nm, as observed in K 3 WOF 7 : Mn 4 + and K 3 MoOF 7 : Mn 4 + .…”

Europium-Doped Calcium Silicate Nanoparticles as High-Quantum-Yield Red-Emitting Phosphors

“…In addition, the color purity was cross-validated with the luminescence photographs of samples. Although all the samples showed red fluorescence emission, − only the 20 nm-sized Ca 2–0.05 SiO 4 : 0.05 Eu 3+ revealed the most prominent deep red emission under UV lamp irradiation (365 and 254 nm) (Figure b). Conclusively, the Ca 2–0.05 SiO 4 : 0.05 Eu 3+ synthesized with 20 nm silica contains intense red emission, very high color purity, and excellent optical property, which indicates that the obtained phosphor is a potential candidate for solid-state lighting as a red component.…”

A highly efficient Mn4+ activated Nb-based oxyfluoride red fluorescent material with excellent water stability: preparation and performance analysis

“…However, compared with the Nb 5+ ion (0.64 Å), Mn 4+ ion has a smaller ionic radius (0.53 Å), so the cell volume will shrink. 18…”

“…17 Hou et al successfully synthesized Na 2 NbOF 5 :Mn 4+ via a hydrothermal method. 18 Dong et al synthesized BaNbOF 5 :Mn 4+ . 19 He's team synthesized Cs 2 MoO 2 F 4 and CsMoO 2 F 3 by using the coprecipitation method.…”