Photoluminescence characteristics of energy transfer between Bi3+ and Eu3+ in LnVO4: Eu, Bi (Ln = Y, La, Gd)

Rare earth ion doped insulators have attracted a great deal of interest due to their wide variety of applications, including phosphors. With increasing Bi3+ concentration, the band edge shifts to longer wavelengths, the band edge in the excitation spectrum moves from ∼254 to ∼330 nm when the Bi3+ concentration is increased from 0 to 3 mol%. Moreover, with increasing Eu3+ concentration, the intensity of the excitation spectra and the red emission was continuously increased up to the Eu3+ concentration of 3 mol%. However, at Eu3+ concentrations of more than 3 mol%, the intensity of the red emission was decreased and in the case of the excitation spectrum, no shift of the band edge to longer wavelength was observed, but only the intensity of excitation spectra was increased.