Poly(3-methylthiophene)/Tungsten oxide hybrid materials for highly efficient electrochromic devices

Abstract Enhanced electrochemical and optical properties of poly(3-methylthiophene)/tungsten oxide (PMeT/WO3) hybrid nanostructure based electrochromic devices (ECDs) are presented. Hybrid nanostructures were prepared by electrodeposition technique in the presence of four different ionic liquids; 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (BMIMTFSI) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPTFSI). The electrochromic behaviors of the ECDs were investigated using cyclic voltammetry, chronoamperometry and transmittance measurements. PMeT/WO3/BMIMTFSI based ECD revealed excellent electrochromic properties of broad optical modulation (57.92%) and great coloration efficiency (398.32 cm2/C). Morphological structures of the thin films were examined by a scanning electron microscope (SEM), which showed that remarkable optical properties of PMeT/WO3 hybrid synthesized in BMIMTFSI medium can be attributed to the spongy network structure. The improved performance of the PMeT/WO3 hybrid electrodes and the facile synthesis through electrodeposition method demonstrate a viable strategy for preparing fast assembling high-performance hybrid electrodes for a wide variety of electrochemical devices.