Hexyl-derivatized poly(3,4-ethylenedioxyselenophene): Novel highly stable organic electrochromic material with high contrast ratio, high coloration efficiency, and low-switching voltage

The use of novel polyselenophenes as electrochromic (EC) materials was investigated. The poly(3,4-ethylenedioxyselenophene) (PEDOS) films were electrodeposited onto indium-tin-oxide (ITO) coated glass having dimensions of 3.2 cm × 0.7 cm at a constant potential of 0.93 V versus Ag/AgCl and passing charge of 0.03 C to form a film with a thickness of ≈ 100 nm. PEDOS film obtained under these conditions has a band gap of ca. 1.42 eV. Introduction of alkyl chains onto the polymer backbone significantly improved the EC properties of PEDOT derivatives. The band gap of PEDOS-C₆ was estimated to be 1.54 eV (805 nm), which is about 0.12 eV higher than for PEDOS. It was observed that polyselenophene derivatives exhibit excellent characteristics for EC applications.