1?x Tb 3+ xWO 4 green-emitting phosphors]]>

摘要

AbstractA series of monophasic Tb3+(2, 5, 7, 10 and 15at%) doped PbWO4phosphors were successfully prepared via hydrothermal method. X-ray diffraction patterns revealed that the prepared samples possess a high crystallinity with tetragonal scheelite-type structure. FT-IR and Raman analysis exhibited a WO stretching peak of WO42?group, which is also related to the scheelite structure. UV–visible diffuse reflectance spectra indicated a reduction in the optical band gap with the replacement of Pb2+by Tb3+ions. The presence of strong and intense emission peaks characteristic of Tb3+with the dominant peak at 545nm (green,5D4→7F5transition) under UV irradiation at 320nm demonstrated an efficient energy transfer from the host to Tb3+ions. Using Van Uitert's model, the concentration quenching mechanism between Tb3+ions in PbWO4:Tb3+phosphor was attributed to a dipole–dipole interaction and the critical distance was determined to be ~12?. The decay lifetimes and CIE chromaticity co-ordinates of PbWO4:Tb3+phosphors were also investigated in detail. These prepared materials might serve as a potential phosphor for LED applications.展开▼