A highly efficient Mn⁴⁺ activated Nb-based oxyfluoride red fluorescent material with excellent water stability:...

In this study, an efficient non-rare earth Mn⁴⁺-doped K₃(NbOF₅)(HF₂) red fluorescent material was synthesized by using the coprecipitation method. Replacing KF with K₂CO₃ effectively solved the problem that KF was difficult to stir due to its strong water absorption. The sample was composed of rods. The excitation spectra consisted of two strong excitation peaks at 366 nm and 468 nm. The emission spectra consisted of a series of narrow-band emissions between 580 nm and 680 nm. Besides, the luminescence quantum efficiency (QE) reached 84.3% under the excitation of 468 nm. The fluorescent lifetime of K₃(NbOF₅)(HF₂):Mn⁴⁺ was less than 4 ms, which can achieve fast response display in backlight display applications. The WLED was fabricated with K₃(NbOF₅)(HF₂):Mn⁴⁺ and commercial YAG:Ce³⁺ and the commercial InGaN blue chip. At a 30 mA drive current, the WLED device exhibited excellent luminescence properties. The correlated color temperature (CCT) was 3853 K, the R_a was 90.1 and the luminous efficiency was 310.432 lm W^-1. Therefore, K₃(NbOF₅)(HF₂):Mn⁴⁺ has very broad prospects in WLED lighting and backlight display applications.