Room temperature synthesis of highly transparent CuO and Cu(OH)2 nanowire films via a simple wet chemical method

This paper introduces a facile synthesis method comprising the use of a wet chemical method of a CuO/Cu(OH)2 nanowire (NW) film transformed from a Cu layer, and its utilities of transparency, anti-fogging, and self-cleaning are demonstrated. Two key parameters are considered for achieving high transparency: the thickness of the Cu layer and the reaction time in the wet chemical solution. A 40-nm-thick Cu layer deposited by a thermal evaporator is used to form CuO/Cu(OH)2 NWs with a reaction time of 60 s in an alkaline solution containing sodium hydroxide and ammonium persulfate at room temperature. The CuO/Cu(OH)2 NW film formed on a glass substrate has a transmittance of 91% in the visible wavelength range. Owing to the intrinsic hydrophilic nature of the CuO/Cu(OH)2 NWs, the film exhibits excellent anti-fogging characteristics. In addition, the CuO/Cu(OH)2 NW film coated with polydimethylsiloxane of hydrophobic nature exhibits superhydrophobic and self-cleaning properties. The synthesis method proposed in this study is simply scalable and applicable to non-planar surfaces and diverse substrate materials, including polymers and metals.