Non-enzymatic electrochemical detection of glucose with and without the presence of insulin using rGO/ZnO

International audienceIn the present work, the combination of the electrophoretic deposition of ZnO nanostructures with size not exceeding 50 nm, and the reduced graphene oxide (rGO) on gold electrodes was performed to study the non-enzymatic electrochemical detection of glucose. The effect of insulin insertion on glucose detection and regulation was studied and the electrochemical responses were compared with and without this molecule. The results showed that the GO/insulin/ZnO electrode is much more sensitive for the glucose detection, in addition to its ability to drop the insulin protein hormone under a negative voltage. That bears interest as dual function sensor for detection and regulation of glucose

Microstructured ZnO-ZnS composite for earth-abundant photovoltaics: Elaboration, surface analysis and enhanced optical performances

International audienceIn this paper, ZnO-ZnS composite structure is proposed as a new efficient and earth-abundant absorber material for thin-film solar cells (TFSCs). Promising elaboration strategy based on combining vacuum thermal evaporation technique and oxidation process under an annealing temperature of 500°C was used to prepare ZnO-ZnS composite with high sun-light absorption capabilities. The fabricated microstructure was then characterized by Scanning Electron Microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and UV–Visible absorption spectroscopy. The influence of the annealing time on the structural and optical performances of the prepared samples was investigated. Surface analysis demonstrated the ZnO decoration of ZnS thin-film, where SEM images showed dense and pinhole-free ZnO-ZnS composite with micrometer-sized grains and a few voids visible at thin-films surface. Optical characterization showed that the prepared thin-film absorber exhibits an optical band-gap of 2.65 eV with a high Total Absorption Efficiency (TAE) of 62% and an absorption coefficient exceeding 2 × 104 cm−1. In addition, I-V characteristics under dark and 1-sun illumination of the microstructured ZnO-ZnS composite were extracted. It was revealed that the proposed absorber showcases a high visible photoresponse. Therefore, promoting effective light-scattering effects, this innovative ZnO-ZnS composite offers a sound pathway to prepare alternative low-cost absorbers for the future development of TFSCs