10.1007/s40089-017-0206-2

Morphology and photoluminescence of self-assembled CaWO4:Sm3+ microspheres: effect of pH and surfactant concentration

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  • Goutam Singh Ningombam1,
  • Rajmuhon Singh Nongmaithem*1,
  1. Department of Chemistry, Manipur University, Imphal Manipur, 795003, IN
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Published in Issue 2017-03-08

How to Cite

Ningombam, G. S., & Nongmaithem, R. S. (2017). Morphology and photoluminescence of self-assembled CaWO4:Sm3+ microspheres: effect of pH and surfactant concentration. International Nano Letters, 7(2 (June 2017). https://doi.org/10.1007/s40089-017-0206-2
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Abstract

Abstract Self-assembled CaWO 4 :Sm 3+ microspheres were prepared via surfactant (sodium dodecyl sulfate) mediated hydrothermal method. The effect of pH and the concentration of surfactant on the morphology and photoluminescence of the synthesized phosphors have been studied. Samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence spectroscopy. The microspheres were found to have an average size of 1–2 µm. They were mesoporous in nature and constituted of nanocrystals of about 10–30 nm dimension. The TEM images revealed the interlinking framework of the nano-sized constituents which consequently lead to the formation of mesoporous microspheres. The lowering of pH causes a slight reduction in the size of microspheres which could have been attributed to loss of OH from the nanoparticle surface and subsequent retardation in the adsorption of growing molecular CaWO 4 :Sm 3+ units. Also, as pH increases, crystallinity decreases. The increase in amount of SDS reduced the crystallinity of the materials, destroyed the monodispersity of microspheres and lowered the luminescence output. It was found that lower pH and higher monodispersity of microspheres are quite favourable for high luminescence output.

Keywords

  • CaWO4 microspheres,
  • Hydrothermal synthesis,
  • Lanthanides,
  • Luminescence
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