White light emission from Sm3+/Tb3+ codoped oxyfluoride aluminosilicate glasses under UV light excitation

In this paper, we report on the absorption and photoluminescence properties of oxyfluoride aluminosilicate and boro-aluminosilicate glasses codoped with Sm3+ and Tb3+ ions. The differential thermal analysis profiles of these glasses have been obtained to confirm their thermal stability. From the measured absorption spectrum, Judd-Ofelt (J-O) intensity parameters (Omega(2), Omega(4) and Omega(6)) have been evaluated for the Sm3+ ion. When excited by ultraviolet light these glasses emit a combination of blue, green and orange-red wavelengths forming white light. The ratio of the intensities of orange-red to green emissions can be tuned by varying both the concentration of the Sm3+ ion and the composition of the glass matrix. The excitation and emission spectra have shown a self- quenching effect for the Sm3+ ions and an efficient energy transfer from Tb3+ : D-5(4) -> Sm3+ : (4)G(5/2) was observed which was also confirmed by the decay lifetime measurements.