Study of structural, optical and electrochemical properties of ZnO nanostructures and ZnO-PANI nanocomposites

Abstract

In this study, different morphologies like plate, flower, spherical particles and flakes of ZnO, which have been prepared by simple sol gel method using Sodium dodecyl Sulphate (SDS), Trisodium Citrate, and Cetyl trimethyl ammonium bromide (CTAB) as different stablizers have been reported. These products have been systematically investigated by UV-Visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), x-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Photoluminesecence (PL) techniques. ZnO-PANI nanocomposites films prepared on ITO, and characterzied by XRD and electrochemical techniques. Microstructural details like lattice parameters, lattice volume, crystalline size and crystal phase have been determined from reitveld refinement method of X-diffraction pattern. FESEM technique shows that ZnO nanostructures morphology can be changed from ZnO nanoplate like shape to ZnO nanoflowers assembled with nanorods, ZnO nanoflakes and ZnO spherical particles when Trisodium Citrate, CTAB and SDS used as additives, respectively. Photoluminescence technique shows that there is slight red shift in the UV region and blue shift in the visible region with the addition of surface active molecules to ZnO, with concomitant decrease in the relative intensity of emission peaks. This indicates that the defects in the ZnO structure have been decreased as CTAB, SDS and Trisodium citrate added into the precursor solution. Cyclic voltammetry results reveal that the current intensity of PANI enhances with the addition of ZnO and surfactant modified ZnO. The urea biosensor, fabricated using urease enzyme on the trisodium citrate assisted ZnO/PANI/ITO nanocomposites, exhibits linearity in the concentration range of 10-80 mg dl-1 with detection limit of 2 mg dl-1 and sensitivity 7.30 μA mM-1 cm-2