An optical study of heterojunction n-ZnO/p-CuO nanosheets and detection of n-butanol vapour at room temperature

Herein, we report our work on ZnO/CuO mesoporous nanocomposite synthesized via a simplistic and cost-effective Co-precipitation technique. The heterostructure was examined for structural, morphological, optical, and gas-sensing properties for pure ZnO, CuO and ZnO/CuO nanocomposite at room temperature. The Bandgap, refractive index and transmittance percentage were determined for the as-prepared samples. The gas sensing study has been systematically introduced to report how the nanocomposite can enhance the sensing capabilities. The nanostructured materials offer good point defects (oxygen vacancies) and high surface area that attributes stronger gas adsorption via active sites for enhanced gas sensing performance. The heterojunction in the n-ZnO/p-CuO nanocomposite gas sensor has exhibited strong sensing performance at low concentrations of n-butanol (5–20 ppm) with a sensor response of 247% and a quick response of 19 s and recovery time of 11 s, which were explained in terms of the hole accumulation layer (HAL) and the quantum confinement effects in the nanocomposite. The ability of sensing a low n-butanol concentration at room temperature provides a feasible path for practical gas sensing application of these ZnO/CuO nanocomposites. Graphical abstract