Microwave-assisted synthesis of PbWO_4 nano-powders via a citrate complex precursor and its photo-luminescence

摘要

Nanocrystalline lead tungstate (PbWO_4) powders, which have scheelite-type structure, were successfully synthesized at low temperatures using a modified citrate complex method assisted by microwave irradiation. The citrate complex precursors were heat-treated at temperatures from 300 to 600 deg C for 3 h. Crystallization of the PbWO_4 precursor was detected at 400 deg C, and completed at 500 deg C. Nanocrystalline PbWO_4 powders heat-treated between 400 and 600 deg C primarily showed spherical and disperse morphology. The average crystallite sizes of PbWO_4 were between 17 and 28 nm at temperatures between 400 and 600 deg C, showing a tendency to increase with the temperature. The PbWO_4 powders prepared at 600 deg C showed the strongest photoluminescent intensity, which was ascribed to the higher crystallinity and homogeneous particle morphology.