Photoluminescence, thermal properties and energy transfer mechanism of Ce3+, Tb3+ co-activated Sr8Si4O12Cl8 phosphor

A series of chlorosilicate Sr8(1 − x − y)Si4O12Cl8: xCe3+, yTb3+ (0 ≤ x ≤ 0.04, 0 ≤ y ≤ 0.06) phosphors were synthesized by solid state reaction. XRD, diffuse reflection spectra, excitation and emission spectra and thermal quenching are used to investigate the structure, photoluminescence and thermal properties. The results show that Ce3+ doped Sr8Si4O12Cl8 can be efficiently excited by the UV light from 250 to 370 nm, and present a broad band emission from 340 to 550 nm. With the doping of Tb3+, the energy transfer from Ce3+ to Tb3+ obviously occurs, and the mechanism is carefully studied by luminescence spectra, energy-transfer efficiency and decay times. By adjusting the ratio of Ce3+/Tb3+, the emission color of Sr8Si4O12Cl8: Ce3+, Tb3+ locates at purplish blue, cold white and yellow-green region with the chromaticity coordinates changing from (0.18, 0.13) to (0.35, 0.47). The results indicate that the samples SSL: Ce3+, Tb3+ could serve as a promising single phase white emitting phosphor.