Hydrothermal synthesis and photoluminescence properties of cerium-doped cadmium tungstate nanophosphor

Abstract

The present paper reports synthesis and photoluminescence studies of cadmium tungstate (CdWO4) and cerium-doped cadmium tungstate. The samples were synthesised by low cost and low temperature hydrothermal method and characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photoluminescence analysis. XRD pattern reveals that the CdWO4 has monoclinic wolframite structure. The FTIR spectrum of cerium-doped CdWO4 exhibits broadband below 700 cm−1 which is due to the δ (Ce–O–C) mode. The TEM images show that size of particle is approximately 60–120 nm in both samples. A broad intense peak was observed at 474 nm when the samples were excited with 263 nm. A broad intense peak was observed at 475 nm when the samples were excited with 600 nm. The intensity of the 474 nm peak decreases with increase in cerium doping concentration. The observation of 475 nm peak when excited with 600 nm is upconversion luminescence. This upconversion emission is due to energy transfer upconversion process involving Cd2+ ions and [WO6]6− ions. Ce3+ ion is responsible for the peak shift of 6 nm.