Synthesis And Luminescence Properties Of BaWO₄and CdWO₄Nanocrystals

Barium tungstate (BaWO4) and cadmium tungstate (CdWO4) crystals areinorganic functional materials, have good latent capacity and wide developmentprospects in the future. Nowadays, the research on the properties, synthesis,reaction mechanisms and the application of BaWO4and CdWO4nanocrystals hasgained more and more attention. If we can explore a simple synthesis technology,and tailor the structure, size, morphology and properties of nanomaterialsreasonably, it will have important significance for improving the level ofpreparation and application of BaWO4and CdWO4nanocrystals.In this paper, BaWO4and CdWO4nanocrystals were prepared via a simplehydrothermal method and deposition method, respectively. The influences ofdifferent reaction factors on the composition and morphology of products arestudied. And the possible formation mechanisms were proposed. The luminescenceproperties of products were studied.BaWO4micro/nanoparticles with different morphologies were prepared via asimple hydrothermal method, using SDBS and P123as surfactants, respectively. Itwas found that surfactants still have strong effect on the morphology of BaWO4byhydrothermal method. And the possible emission mechanisms of BaWO4arediscussed. We believe that the PL emission maybe caused by the structural defects.In addition, the dendrite assemblies of BaWO4nanoparticles were prepared via asimple deposition method at room temperature with the induction of SDBS for longtime. The surfactants and react time have strong effect on the morphology ofBaWO4at room temperature. It has important significance to synthesis BaWO4nanocrystals with special morphologies, because the properties of nanomaterials aredependent on its structure and morphology.CdWO4nanorods were synthesized via a simple hydrothermal method in thepresence of SDBS. The results show that, the aspect ratio of CdWO4nanorodsincreases from3-5to20-25with the increase of the concentration of SDBS. The photoluminescent intensity of CdWO4nanorods increases as the increase of aspectratio. It is indicated that concentrations of surfactant have strong effect on themorphology of CdWO4nanorods, and the photoluminescence of CdWO4nanorodsare influenced by its morphology.Based on the formation of CdWO4nanorods, Eu3+doped CdWO4nanorodswere prepared by a simple hydrothermal method with the same preparation process.The emission spectra of Eu3+doped CdWO4nanorods change considerably with thecontent of Eu3+. The PL spectra revealed that the band of CdWO4nanorods wasdecreased with the content of Eu3+increasing, but the band of Eu3+ion wasincreased obviously. The band of Eu3+ions will reach the strongest at the sampleCd0.95Eu0.05WO4. The results show that there has an efficient energy transfer fromCdWO4nanocrystalline to the doping Eu3+ions.