Spectroelectrochemical and Electrochromic Characterization of a Conductive Polymer Bearing Both Electron Donor and Acceptor Groups

Abstract

A monomer precursor of polyterthiphene derivative bearing both electron donor (-NH2) and acceptor (–COOH) groups (3-([2,2′:5′,2″-terthiophen]-3′-yl)-5-aminobenzoic acid, TABA) was newly synthesized and characterized. The comparison analysis was performed forpTABA with a single acceptor or donor group bearing polymer. The frontier orbital calculation for the monomer reveals the intermolecular electron movement from donor to acceptor through the backbone. The electrical study confirmed that the conductivity of the functionalized polymer increased from 0.11 S cm−1 (with single donor group) to 0.24 S cm−1 (with single acceptor group) through 0.19 S cm−1 (for both donor and acceptor groups), as a result of stabilization of quinoid form on the polymer backbone. Derivative cyclic voltabsorptometry (DCVA) obtained for pTABA confirmed the formation of neutral, polaron, and bipolaron at 470 nm (at +1.07/+0.80 V), 781 nm (at +1.07/+0.80 V), and 950 nm (at +1.30/+1.19 V), respectively. The absorption bands of radical species were blue-shifted by the donor group functionalized polymer and red-shifted by the acceptor group. The electrochromic performance of polymer bearing both donor and acceptor groups achieved nine colors between orange (0.0 V) and midnightblue (1.4 V) compared with that of single functional groups displaying two or three colors.