Solid solution of novel LixByGdEu (WO4)2 (B=Na, K) red phosphors: Influence of Na/K substitution on microstructures, Judd-Ofelt and luminescence properties for WLED applications

A novel scheelite‐type LiCaGd(WO4)3:Eu3+ red phosphors with prominent thermal stability and high quantum efficiency

“…Obviously, the PLE spectrum is composed of a wide excitation peak and some narrow and sharp excitation peaks. The wide excitation band ranging from 200 to 300 nm is ascribed to the CTB, which mainly contains two parts: the charge transfer from O 2− to Eu 3+ ion and the charge migration from O 2− to W 6+ in the matrix 23 . Other narrow peaks in the range of 300 to 500 nm are the 4 f ‐4 f characteristic transitions of Eu 3+ ions, attributing to 7 F 0 → 5 H 3 (320 nm), 7 F 0 → 5 D 4 (362 nm), 7 F 0 → 5 L 7 (383 nm), 7 F 0 → 5 L 6 (395 nm), 7 F 0 → 5 D 3 (416 nm), and 7 F 0 → 5 D 2 (465 nm), respectively 24 .…”

“…W 6+ in the matrix. 23 Other narrow peaks in the range of 300 to 500 nm are the 4f-4f characteristic transitions of Eu 3+ ions, attributing to 7 F 0 → 5 H 3 (320 nm), 7 F 0 → 5 D 4 (362 nm), 7 F 0 → 5 L 7 (383 nm), 7 F 0 → 5 L 6 (395 nm), 7 F 0 → 5 D 3 (416 nm), and 7 F 0 → 5 D 2 (465 nm), respectively. 24 The 7 F 0 → 5 L 6 transition peak at 395 nm is the strongest one, which means that LCGWO:Eu 3+ phosphor can be effectively excited by near UV light.…”