Novel powellite-based red-emitting phosphors: CaLa1−xNbMoO8:xEu3+ for white light emitting diodes

We report the photoluminescence properties of a novel powellite-based red-emitting phosphor material: CaLa1−xNbMoO8:xEu3+ (0.01, 0.03, 0.05, 0.1) for the first time. The photoluminescence investigations indicated that CaLa1−xNbMoO8:xEu3+ emits strong red light at 615 nm originating from 5D0→7F2 (electric dipole transition) under excitation either into the 5L0 state with 394 nm or the 5D2 state with 464 nm, that correspond to the two popular emission lines from near-UV and blue LED chips, respectively. When compared with emission intensity from a CaMoO4:Eu3+, the emission from CaLaNbMoO8:Eu3+ showed greater intensity values under the same excitation wavelength (394 nm). The enhanced red emission is attributed to the enhanced f–f absorption of Eu3+. These materials could be promising red phosphors for use in generating white light in phosphor-converted white light emitting diodes (WLEDs).

Graphical AbstractNovel powellite-based red-emitting phosphors: CaLa1−xNbMoO8:xEu3+ (x=0.01, 0.03, 0.05, 0.1) have been prepared and characterized for the first time. The photoluminescence investigations indicated that CaLa1−xNbMoO8:xEu3+ emits strong red light at 615 nm originating from 5D0→7F2 (electric dipole transition) under excitation either into the 5L0 state with 394 nm or the 5D2 state with 464 nm. The red emission of CaLa0.95NbMoO8:0.05Eu3+ is 10 times stronger than that of CaMoO4:0.05Eu3+ under the same excitation wavelength (394 nm).Figure optionsDownload full-size imageDownload as PowerPoint slide