The size effect on the energy transfer in Bi3+–Eu3+ co-doped GdVO4 nanocrystals

Abstract

Nanocrystals of GdVO₄ co-doped with various concentrations of Bi³⁺ and a constant concentration of Eu³⁺ ions (5 mol%) were synthesized by Pechini's method and annealed in the range of temperature from 750 °C to 900 °C in order to obtain different sizes of individual crystallites. Upon the excitation of near-UV light, an intense red/orange-red luminescence of Eu³⁺ was observed. Shifting of the maximum and broadening of the excitation band with increasing Bi³⁺ concentration were also observed. In particular, the influence of the size effect on the energy transfer in the chain: (O²⁻–V⁵⁺) charge transfer → (Bi³⁺–V⁵⁺) charge transfer → Eu³⁺ ions was determined and analysed.