Luminescence properties of Tb[sup 3+]–Sm[sup 3+] codoped glasses for white light emitting diodes

Photoluminescence properties of silicate and borosilicate glasses codoped with Tb3+ and Sm3+ions have been characterized by excitation and emission spectroscopies. When excited by ultraviolet light the glasses emit a combination of green and orange-red wavelengths giving 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 an the composition of the glass matrix. The excitation and emission spectra show a self-quenching effect for the Sm3+ions and an energy transfer from Tb3+ (5D4) to Sm3+ (4G 5∕2)