Work function analysis of photo-enhanced triethylamine adsorption impact on Au embedded CeO2 coated ZnO hybrid nanostructures: An investigation by scanning kelvin probe

Abstract

This article utilizes a scanning kelvin probe to examine the impact of visible light and volatile organic compounds (VOCs) on an organic/inorganic/noble metal hybrid sensing layer. ZnO/Poly/CeO2/Poly/Au hybrid nanostructures were prepared on ITO substrate by layer-by-layer coating technique. In this case, PAH and DS polymers act as binders. The assembly of Au nanorods (NRs) on the polymer-coated ZnO NRs incorporated with CeO2 nanoparticles (NPs) and its maximum absorbance in the visible light region were studied by the structural and optical characterizations, respectively. The hybrid sensor's optical properties allowed for sizable changes in contact potential difference (CPD) when exposed to light. Although a non-selective interaction was observed, the increased responsiveness to Triethylamine (TEA) under visible light creates coordination bonds between the hybrid molecules. Notably, the surface charge was tuned in the surface of the sensing layer by varying the surfactant to explore the TEA responsiveness. Intriguingly, ZnO/Poly/CeO2 (+) has demonstrated improved adsorption capability towards TEA under irradiation due to the surface oxygen vacancies compared to ZnO/Poly/CeO2 (-). Also, ZnO/Poly/CeO2 (+) exhibited higher selectivity at adsorbing TEA than either ethanol or n-hexane.