Electrochromic properties of poly(3-chlorothiophene) film electrodeposited on a nanoporous TiO₂ surface via a room temperature ionic liquid and its application in an electrochromic device

Poly(3-chlorothiophene) (PClT) was electrochemically synthesized on a nanoporous TiO₂ surface in the ionic liquid 1-butyl-3-metyllimidazolium hexafluorophosphate by galvanostat method to control charge density of 93 mC cm^{- 2}. Spectroelectrochemical analysis presented that the PClT/TiO₂ nanocomposite film had an electronic bandgap of 1.80 eV with a bordeaux color in the reduced form and a dark blue color in the oxidized form. The switching ability of the PClT/TiO₂ nanocomposite film was monitored and the percent transmittance was measured as 12% at 555 nm and 25% at 770 nm. Moreover, a PClT/TiO₂ nanocomposite film based electrochromic device was constructed and its electrochromic properties were also investigated in this paper.