Electrochromic Properties of ‘Trimeric' Thiophene‐pyrrole‐thiophene Derivative Grown from Electrodeposited 6‐(2,5‐di(thiophen‐2‐yl)‐1H‐pyrrol‐1‐yl)hexan‐1‐amine and its Copolymer

Abstract

A centrosymmetric polymer precursor, namely 6‐(2,5‐di(thiophen‐2‐yl)‐1H‐pyrrol‐1‐yl)hexan‐1‐amine (TPHA), was synthesized via a Knorr–Paal reaction using 1,4‐di(2‐thienyl)‐1,4‐butanedione and hexane‐1,6‐diamine. The resultant monomer was characterized by Nuclear Magnetic Resonance (¹H‐NMR). Electroactivity of TPHA was investigated via cyclic voltammetry. The electronic structure and the nature of electrochromism in P(TPHA) and its copolymer with EDOT, (P(TPHA‐co‐EDOT)), were examined via spectroelectrochemistry studies. P(TPHA) switches between claret red neutral state and blue oxidized state. Optical response times for coloring and bleaching processes of the P(TPHA) and P(TPHA‐co‐EDOT) were found as 2.1 s and 1.6 s, respectively.

The copolymer of TPHA was used to construct dual type polymer electrochromic devices (ECDs) against poly(3,4‐ethylenedioxythiophene) (PEDOT). Spectroelectrochemistry and electrochromic switching out of the devices were investigated.

Keywords:

• conducting polymers
• electrochromism
• electrochromic devices
• electrochemical copolymerization

Acknowledgments

The authors gratefully thank the DPT‐2005K120580 and DOSAP program METU.