Re-dispersion and film formation of GdVO 4: Ln 3+ (Ln 3+ = Dy 3+, Eu 3+, Sm 3+, Tm 3+) nanoparticles: Particle size and luminescence studies

Abstract

GdVO 4:Ln 3+ (Ln 3+ = Dy 3+, Eu 3+, Sm 3+, Tm 3+) 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 GdVO 4 formation with increase of VO 43- present in solution. The luminescence study shows an efficient energy transfer from vanadate absorption of GdVO 4 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. © 2012 The Royal Society of Chemistry.