Influence of Eu3+, Bi3+ co-doping content on photoluminescence of YVO4 red phosphors induced by ultraviolet excitation

Rare earth ion doped insulators have attracted a great deal of interest due to their wide variety of applications, including phosphors. YVO4:Eu, Bi phosphor has a broad excitation band consisting of two peaks—one centered at from 260 to 320 nm and the other at a weak band at wavelength of 386–406 nm. Also, the emission spectrum exhibited a weak band for 5D0 → 7F1 at 595 nm and strong sharp peaks at about 616 and 620 nm due to the 5D0 → 7F2 transition of Eu3+. With increasing Bi3+ concentration, the band edge shifts to longer wavelengths, the band edge in the excitation spectrum moves from ∼254 to ∼328 nm as the Bi3+ concentration is increased from 0 to 2 mol%. Moreover, with increasing Eu3+ concentration, the intensity of the excitation spectra and the red emission increased continuously up to the Eu3+ concentration of 3 mol%.