Enhanced photoluminescence via doping of phosphate, sulphate and vanadate ions in Eu3+ doped La2(MoO4)3 downconversion phosphors for white LEDs

Abstract

In this study, the Eu3+ doped La2(MoO4)3 phosphor has been successfully prepared by solid state reaction method. The prepared phosphors are crystalline and the particle size increases in the presence of phosphate, sulphate and vanadate ions. The photoluminescence excitation (PLE) spectrum of the Eu3+ doped La2(MoO4)3 phosphor shows an intense peak centered at 467 nm due to absorption by Eu3+ ions. On the excitation at 467 nm, the Eu3+ doped La2(MoO4)3 phosphor emits strong red emission centered at 614 nm, which is attributed to the 5D0 → 7F2 transition of Eu3+ ions. The emission intensity of the phosphors has been optimized by appropriate selection of the concentration of Eu3+ ions. When the phosphate, sulphate and vanadate ions are incorporated in the thermally stable Eu3+ doped La2(MoO4)3 phosphor the emission intensity of Eu3+ion is enhanced significantly. This occurs due to modification in the local crystal structure and the particle size increase. The CIE diagram shows the presence of emission bands in the visible spectrum. It also shows color tunability with a high color purity of the phosphor. The phosphate, sulphate and vanadate doped La2(MoO4)3: Eu3+ phosphors may act as good candidates for the phosphor converted white LEDs in solid state lighting technology. © 2019 Elsevier Ltd