Studies on Multifunctional Properties of SILAR Synthesized CuO Thin Films for Enhanced Supercapacitor, Photocatalytic and Ethanol Sensing Applications

Abstract

CuO thin films were successfully deposited using a simple, cost-effective and nearly room-temperature successive ionic layer adsorption and reaction routes. The material has been characterized using x-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy. Increase of grain size and decrease of microstrain were observed for a particular level of dipping (30 cycles) and further increase in dipping cycles shows a reverse tendency. The effect of the dipping cycle of the synthesized films on their supercapacitive, photocatalytic and ethanol-sensing performance were investigated. A 30-cycle dipped CuO thin film-based electrode provides a maximum specific capacitance of 585 Fg−1 at the voltage scan rate of 2 mVs−1 from cyclic voltammetry measurement and 554 Fg−1 at a current density of 1 Ag−1 from the charging to discharging curve. This electrode exhibited long-term cycle stability with 92.3% capacitance retention after 4000 cycles. CuO films synthesized for 30 dipping cycles showed the highest photocatalytic activities with 91.1% degradation of methylene blue under exposure to visible light of 200-W energy in a time duration of 4 h. Maximum sensitivity of 67% in the presence of 1500 ppm ethanol at the operating temperature 160°C was obtained for 30 dipping cycles film. Such attractive properties of low cost and facile synthesized CuO thin films makes them a suitable candidate for different commercial applications.