Controlled Synthesis of CaWO₄ Microcrystalline via Surfactant-Assisted Precipitation Method

Abstract

CaWO₄ microcrystallines have been synthesized via a surfactant-assisted precipitation method using cetyltrimethylammonium bromide (CTAB) and /or Polyvinylalcohol (PVA) as surfactants, respectively. The as-prepared CaWO₄ microcrystallines were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectra and photoluminescence spectra (FL). The growth process of these CaWO₄ microcrystallines obtained in the presence of CTAB and PVA has been discussed. The structural characterization results indicate that the obtained CaWO₄ are ellipsolid-like microcrystallines with the average size of ∼350 nm in short axis and ∼800 nm in long axis, and the CaWO₄ microcrystallines possess a pure scheelite structure with a tetragonal symmetry. The FTIR spectra provide the evidence of W–O stretching vibration in [WO₄]²⁻ tetrahedrons at 796 cm⁻¹ and W-O bending bands at 438  cm⁻¹. FL spectra reveal that the CaWO₄ microcrystallines exhibit the only green peak at 430 nm excited by ultraviolet ray (UV) with the wavelength at 220 nm, 240 nm and 260 nm, respectively. The SEM results indicate that the morphology of the CaWO₄ microcrystallines can be affected by the concentration of surfactants.

Keywords:

• CaWO₄ microcrystalline
• surfactant-assisted
• precipitation method

Acknowledgements

This work was supported by the Open Project of State Key Laboratory of Electronic Thin Films and Integrated Devices (UESTC, No.KFJJ201109), the Open Project of State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials (10zxfk27) and Scientific Research Fund of Sichuan Provincial Education Department (No. 12ZA142, 11ZZ013 and 09ZA092).