(180bx) Electrochromic Polymer Nanocomposites

Hybrid electrochromic poly(DNTD) CdSe@ZnS quantum dots (QDs) composite films were prepared using electropolymerization technique at room temperature and their electrochemical properties at different temperatures were investigated by cyclic voltammetry (CV). At room temperature, the composite films exhibited asymmetry in the voltammograms arising from the heterogeneity in the polymer chains and the morphology change caused by the QDs. A more positive cathodic potential than that of the pure polymer films indicated that poly(DNTD) became more difficult to be oxidized as a consequence of the incorporated QDs.  The CVs of these nanocomposite thin films were also carried out at 0 °C to evaluate the temperature effect on their electrochemical properties. The asymmetry in the oxidation/reduction process became more remarkable, and lowered oxidation potentials were observed. Pure poly(DNTD) thin film and its composite thin film with 0.05 wt% QD loading were prepared at 0 °C as well. Their CVs were performed at both room temperature and 0 °C, and were compared with those of the films prepared at room temperature. The morphology, optical, and spectroelectrochemistry (SEC) properties of the thin films were studied using atomic force microscopy (AFM), fluorescent microscope, and UV-Visible spectrometer coupled with the potentiostat, respectively. The obtained uniform thin films turned to be made of nanoparticles under high resolution AFM observation. Fluorescent microscopic observations revealed the fluorescent emission of the nanocomposites with the QDs embedded in the hosting polymer matrix. The nanocomposite thin films exhibited varying absorbance bands when different potentials were applied and the film was observed to turn blue at an applied voltage of 1.4 V vs. Ag/AgCl.