Re-dispersion and film formation of GdVO4 : Ln3+ (Ln3+ = Dy3+, Eu3+, Sm3+, Tm3+) nanoparticles: particle size and luminescence studies

Abstract

GdVO₄ : Ln³⁺ (Ln³⁺ = Dy³⁺, Eu³⁺, Sm³⁺, Tm³⁺) nanoparticles are prepared by a simple chemical route at 140 °C. The crystallite size can be tuned by varying the pH of the reaction medium. Interestingly, the crystallite size is found to increase significantly when pH increases from 6 to 12. This is related to slower nucleation of the GdVO₄ formation with increase of VO₄³⁻ present in solution. The luminescence study shows an efficient energy transfer from vanadate absorption of GdVO₄ to Ln³⁺ and thereby enhanced emissions are obtained. A possible reaction mechanism at different pH values is suggested in this study. As-prepared samples are well dispersed in ethanol, methanol and water, and can be incorporated into polymer films. Luminescence and its decay lifetime studies confirm the decrease in non-radiative transition probability with the increase of heat treatment temperature. Re-dispersed particles will be useful in potential applications of life science and the film will be useful in display devices.