Fast switching electrochromic nanocomposite based on Poly(pyridinium salt) and multiwalled carbon nanotubes

Abstract

This paper represents a simple approach to modulate electrochromic properties of poly (4,4′-(1,4-phenylene)bis (2,6-diphenylpyridinium) triflate) (PV) by the formation of composite material with multiwalled carbon nanotubes. The polymer acts as a functionalizing agent for MWCNTs to prevent their agglomeration enabling the formation of stable dispersions. They were further used to prepare uniform electrochromic films by spin-coating method. The films were characterized by electrochemical and spectroelectrochemical methods. To evaluate the influence of MWCNTs on the electrochromic properties of PV the dispersions with various PV/MWCNTs compositions were studied. Upon the addition of MWCNTs the absorption bands and redox peak potentials of polymer did not change. However, the decrease of the peak separation between reductive and oxidative waves and the significant improvement of switching times (one of the most important properties of electrochromic materials) were demonstrated. At the practically identical optical contrast both coloration and bleaching times decreased that can be explained by the composite film morphology. This effect became significant for high PV concentrations in the initial solution. The decrease of coloration and bleaching times reached 30% and 50%, respectively. The resulting composite material exhibited fast (200–400 ms) response times and could be used as a promising candidate for novel electrochromic devices.