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

GdVO4 : Ln(3+) (Ln(3+) = Dy3+, Eu3+, Sm3+, Tm3+) nanoparticles are prepared by a simple chemical route at 140 degrees 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 Ln(3+) 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.