Tunable and white up-conversion emission from Tm3+-Ho3+-Yb3+/-Nd3+ co-doped GdVO4 phosphors under 808-nm excitation

Lanthanide-doped system with adjustable multicolor and white up-conversion (UC) emission has been developed in GdVO4 (GVO): Tm3+-Ho3+-Yb3+/-Nd3+ phosphors, which are fabricated via a facile solid-state reaction. Herein, we study their phase structures and the Ho3+ concentration effect on their up-conversion emission. Under 980 nm excitation, the Tm3+-Ho3+-Yb3+ tri-doped GVO phosphors exhibit intense luminescence combined with red, green and blue (RGB) emission and the successive energy transfer between Tm3+-Ho3+-Yb3+ ions causes a slight shift in the color coordinates of samples with different doping concentrations. Under 808 nm excitation, the color coordinate of the optimum GVO: Tm3+-Ho3+-Yb3+-Nd3+ phosphor is located at (0.3277, 0.3433), which is closest to the ideal white light emission corresponding to (0.3333, 0.3333). Therefore, it is proved that these phosphors provide potential applications in the fields of displays, lasers and optical telecommunication.