Rapid synthesis strategy of CuO nanocubes for sensitive and selective detection of NO₂

In present work, copper oxide (CuO) films have been successfully synthesized onto a quartz substrate using a simple and catalyst-free thermal evaporation technique and their chemiresistive properties were carried out towards host of target gases. Structural analysis demonstrates the formation of polycrystalline single phase monoclinic CuO. Formation of nanocubes–type of surface morphology of CuO was observed from morphological investigation. Gas sensing results demonstrate that the CuO films, composed of nanocubes (NCs), are highly selective towards oxidizing nitrogen dioxide (NO₂) gas than other target gases along with rapid response and recovery times. CuO sensor films exhibit the maximum response value of 76%–100 ppm NO₂ @150 °C. In addition, CuO films are able to sense as low as 1 ppm concentration of NO₂ gas. The effect of operating temperature on the NO₂ sensing properties of CuO films was thoroughly investigated and reported. Impedance spectroscopy was used to study the interaction mechanism between CuO sensor film and NO₂ gas molecules.