Abstract
Nanocrystalline CuO thin films were deposited for 600, 1200 and 1800s on glass substrate using RF magnetron sputtering technique. The films deposited at room temperature were crystalline and showed Tenorite phase of CuO. The increase in average particle size from 6.67nm to 9.09nm and the thickness from 160nm to 490nm was observed with the increase in deposition time. The optical band gap was decreased from 2.2eV to 1.73eV as the film thickness was increased. The intensity of PL peak showed its maximum for the film deposited for 600s and minimum for 1800s. Some unusual emission peaks were observed due to the quantization effect and lattice/surface defects. The CuO films with different thicknesses could be used as photo-catalysts for the degradation of Methylene blue (MB) from the wastewater. Under the exposure of 200W energy of tungsten lamp, CuO thin films showed excellent photo-catalytic activities. CuO thin film of minimum thickness of around 160nm responded as a best catalyst for MB degradation. The films were very stable and have a speciality to be recycled without much loss of their photo-catalytic activity. These characteristics have proved the high possibility of commercial applications of CuO thin films in environmental remediation.
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•RF sputtered nanocrystalline CuO thin films with different thicknesses.•Decreased optical band gap and PL intensity with increase in thickness.•Highly efficient and reusable CuO thin films for photo-catalytic degradation of methylene blue in visible light.•Excellent photo-catalytic behavior of CuO thin film of least thickness (~160nm) and particle size (~6.67nm).