Tm3+, Dy3+ and Tm3+/Dy3+ co-doped bismuth silicate (Bi4Si3O12, BSO) crystals were successfully grown by the modified vertical Bridgeman method. The crystals have about 80% transmittance in the range from 320 nm to 650 nm except several obvious characteristic absorption peaks corresponding to transitions of 4f electrons of Tm3+ and Dy3+. The luminescence properties for white light emitting diode (w-LED) were investigated. Energy transfer from the Bi3+ ions to the Tm3+ and Dy3+ ions in Tm3+ or/and Dy3+ co-doped Bi4Si3O12 crystal has been established by photoluminescence investigation upon UV excitation. When excited by a proper UV-light, Tm3+ doped BSO crystal shows blue emission band centered at 460 nm ascribed to Tm3+ (1D2→ 3F4), Dy3+ doped BSO crystal shows blue band at 480 nm (4F9/2→ 6H15/2), yellow band at 574 nm (4F9/2→ 6H13/2) and red band at 662 nm (4F9/2→ 6H11/2) of Dy3+ ions. A white light with chromaticity coordinate of x = 0.3298, y = 0.2905 by excitation of 357 nm is achieved from Tm3+/Dy3+ co-doped Bi4Si3O12 crystal. These results indicate that Tm3+/Dy3+ co-doped Bi4Si3O12 as a white emitting crystal has a potential application in white-LED

Keywords: Crystal growth, Tm3+/Dy3+:Bi4Si3O12, Photoluminescence, Energy transfer, White-LED.