Novel green/red oxyfluoride phosphors with excellent optical properties for near-UV excited white light emitting diode.

[Display omitted] • Novel eye-sensitive Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :Tb3+/Mn4+ were synthesized by simple co-precipitation strategy. • Red phosphor presents extremely strong ZPL at ∼ 625 nm and high color purity. • Red and green phosphors exhibit inherently outstanding thermal stability and moisture resistance. • Red and green phosphors coated directly on UV chip can achieve white emission. • The fabricated WLED devices show excellent electroluminescent properties. Novel eye-sensitive Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :Tb3+ green and Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :Mn4+ red oxyfluoride phosphors with extremely strong absorption in the UV region were designed and synthesized by simple co-precipitation strategy. Particularly, Tb3+ ions were doped in this matrix for the first time, which greatly improves their absorption efficiency in the near ultraviolet region (367 nm) and emits sharp green light (544 nm). In addition, the Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :Mn4+ red phosphors have strong zero phonon line (ZPL) emission at 625 nm, which is conducive to improving the sensitivity of human eye and color purity. Meanwhile, the optical properties of the red phosphor are significantly enhanced via doping K+ cations as charge compensators. Crystal field environment and nephelauxetic effect of the as-prepared phosphors before and after K+ cation doping were systematically analyzed. Moreover, these synthesized red/green phosphors have good thermal stability and moisture resistance. Remarkably, the as-prepared Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :5%Mn4+ or K 0.9 Ba 2.1 Nb 2 O 2 F 12 (H 2 O) 2 :5%Mn4+ red phosphors can be directly mixed with the as-synthesized Ba 3 Nb 2 O 2 F 12 (H 2 O) 2 :13%Tb3+ green phosphor coating on 365 nm near-ultraviolet LED chip to package WLED devices with excellent electroluminescence performance. These findings are conducive to opening an avenue for screening the unique structure of optical materials. [ABSTRACT FROM AUTHOR]