Luminescent properties and energy transfer of Tm3+/Dy3+ co-doped oxyfluoride borate glasses for white LEDs

Tm3+/Dy3+ co-doped oxyfluoride borate glasses with composition of 25CaF(2)-25ZnO-6P(2)O(5)-44B(2)O(3) (mol%) for white light-emitting diodes were synthesized by a conventional melting-quenching method. The glass structure, spectroscopic properties and decay time profiles were characterized by XRD and FT-IR, optical and fluorescence spectrum measurements. Under 354 nm excitation, the color tones change from light blue (0.3004, 0.2646) to warm white (0.3626, 0.3642) by increasing concentration of Tm3+. The shortening of the Dy3+ emission decay time in presence of Tm3+ suggests that Dy3+/Tm3+ non-radiative energy transfer occurs. By using the Inokuti-Hirayama model, it is inferred that an electric quadrupole-quadrupole interaction might be the dominant mechanism involved in the energy transfer. The results suggest that the as-prepared Tm3+/Dy3+ co-doped oxyfluoride borate glasses may be promising candidate in white LEDs and other display devices.