Effect of Ultrasonic‐assisted Preparation Methods on Structure,Morphology and Optical Properties of Nanosized Cupric Oxide

Cupric oxide is a p‐type semiconductor with a narrow band‐gap which is suitable for catalysis, electrochemical cells, field emission devices and gas sensor applications. Despite considerable efforts devoted to the preparation of the nanosized CuO, there is a lack of information about ultrasonic‐assisted (US) preparation methods. Nanosized cupric oxide was successfully prepared through different ultrasonic‐assisted (US) preparation methods. Furthermore, the influence of preparation method on the structure, morphology and optical properties of nanosized CuO has been reported. XRD patterns were identical to the single‐phase pure CuO with a monoclinic structure. The enhancement of the crystallinity and crystallite size was observed for the sample prepared through the US thermal decomposition. The absorption band of CuO nanocrystals prepared through the US liquid hydrolysis shows a clear red shift of about 40 nm compared to those obtained with other preparation methods. Our results indicated that almost spherical CuO nanoparticles with an average size of 65 nm were prepared during the US thermal decomposition, while CuO rod‐like nanostructures with an average diameter of about 16 nm were obtained via the US liquid hydrolysis method. The band gap values of nanosized CuO samples were larger than the reported value for the bulk CuO. Synthesized CuO samples by US methods with adjustable and controllable properties make the applicability of cupric oxide even more versatile.