Poly(2,5-dimethoxyaniline) based electrochromic device

Poly(2,5-dimethoxyaniline) (PDMA) was deposited as conducting film on indium tin oxide (ITO) coated glass and used as an electrode in an electrochromic device assembly. Film of tungsten oxide (WO3) on ITO glass was used as the other electrode with LiClO4 doped gelled polyethylene oxide (PEO) as polymer electrolyte. An electrochromic device with the following configuration was assembled: ITO/PDMA∥LiClO4–PC–PEO (400,000)∥WO3/ITO. Cyclic voltammetry was used to characterize the single electrodes, ITO/PDMA, ITO/WO3, and the device. The coulombic efficiency (CE) of the ITO/PDMA and ITO/WO3 electrodes were close to 100%. The optical contrast of the single electrodes and the device were determined by UV–visible spectroelectrochemical studies. A visible contrast in color upon switching the potential from −1.50 to +1.50 V was noticed for the device. The device was pale yellow at −1.50 V and dark green at +1.50 V. The CE of the device was 92%. Double potential chronamperomtry was used to determine the response time of coloring and bleaching processes. The bleaching process was found to be faster than coloring. The stability of the device was established by polarizing the device and recording the UV–visible spectrum in open circuit conditions. Bleaching state is more stable than coloring state.