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Structural and Optical Properties of Ca0.9Cu0.01WO4 Solid Solution Synthesized by Sonochemistry Method at Room
Francisco Xavier Nobre1, Içamira Costa Nogueira2, Giancarlo da Silva Souza3
1Campus Coari, Federal Institute of Amazon, Coari, Amazonas 69460-000, Brazil.
Inorganic Chemistry
|April 14, 2020
Summary
We synthesized pure and copper-doped calcium tungstate (CaWO4) using sonochemistry. Copper doping reduced the band gap and shifted photoluminescence, indicating potential for new optical materials.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Nanotechnology
Background:
- Calcium tungstate (CaWO4) is a promising material for luminescence applications.
- Doping with transition metals can tune the optical properties of CaWO4.
- Sonochemistry offers a versatile method for synthesizing nanomaterials at room temperature.
Purpose of the Study:
- To synthesize pure and copper-doped calcium tungstate (Ca0.99Cu0.01WO4) solid solutions.
- To characterize the structural, morphological, and optical properties of the synthesized materials.
- To investigate the effect of copper doping on the band gap and photoluminescence of CaWO4.
Main Methods:
- Room-temperature synthesis via sonochemistry.
- Structural and phase analysis using X-ray diffraction (XRD) and Rietveld refinement.
- Morphological characterization by field emission scanning electron microscopy (FESEM).
- Elemental analysis using energy-dispersive X-ray spectroscopy (EDX).
- Optical band gap determination and photoluminescence (PL) spectroscopy.
Main Results:
- Tetragonal phase (space group I41/a) confirmed for both pure and doped CaWO4.
- Spherical agglomerated structures composed of nanoparticles were observed.
- Optical band gap decreased from 4.0 eV for CaWO4 to 3.45 eV for Ca0.99Cu0.01WO4.
- Photoluminescence emission maximum shifted from 522 nm (CaWO4) to 475 nm (Ca0.99Cu0.01WO4).
- Increased PL intensity in blue and green regions due to O 2p, Cu 3d, and W 5d electronic transitions.
Conclusions:
- Sonochemistry is effective for synthesizing pure and copper-doped CaWO4 at room temperature.
- Copper substitution in CaWO4 leads to significant changes in optical properties, including band gap reduction and blue-shifted photoluminescence.
- The observed optical property modifications suggest potential applications for copper-doped CaWO4 in optoelectronics and lighting.
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