Influence of Annealing on the Structural, Morphological, Photoluminescence and Visible Absorption Properties of Mg Doped CuO Micro Grains.

Abstract

Narrow band gap oxide materials that harvest visible light have gained considerable attention for numerous visible light mediated applications. In this current work, a typical Mg doped CuO bulk material was prepared by a simple wet chemical method. The prepared material was annealed in three different temperatures viz.; 300°C, 400 and 500°C in air atmosphere to tune the optical band gap. XRD studies reveal that the average crystallite size increases with increase in annealing temperature. FESEM images of all the samples show their bulk nature with different grain sizes and morphologies. XPS survey scan spectra exhibit photoelectron emissions of Cu2p, O1s and Mg 1s with binding energies 933.69eV, 533.41eV and 1304.2eV for all the samples and validated the effective incorporation of Mg ions into the CuO lattice. PL spectra reveal the polychromatic UV- visible luminescence bands for all the annealed samples, whereby the PL intensity is found to be decreasing as the annealing temperature increases. Finally, the band gap decreases with annealing temperature and indicates that the sample annealed at 500°C can be exploited for visible light assisted applications such as solar cells, photocatalysis and photoelectrochemical cell.