Investigation on surface functionalized ZnO nanoflowers with Cu atoms for visible light driven applications

ZnO nanoflowers (NFs) were synthesized by the reflux condensation route and are functionalized with Cu atoms via the co-precipitation method. The functionalization of Cu was confirmed by X-ray diffraction, energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Ultraviolet (UV)-Visible diffuse reflectance spectroscopy revealed that the surface-modified ZnO NFs showed higher absorbance and better optical conductivity in the visible region compared to pristine ZnO NFs. The room temperature photoluminescence (PL) emission spectra show that the functionalization of Cu significantly reduces the oxygen vacancies. The strong and broad visible region photo response of Cu functionalized ZnO (Cu/ZnO) NFs was due to the localized surface plasmon resonance (LSPR) exhibited by the presence of plasmonic Cu atoms. Among various concentrations, 0.02 M Cu/ZnO NFs showed better structural and morphological features and enhanced optical performance in the visible region, making it a promising candidate in visible light photodetection applications.