Solution processable donor acceptor type dibenzothiophen-S,S-dioxide derivatives for electrochromic applications

In this report, we highlight the synthesis and optical and electrochromic properties of dibenzothiophen-S,S-dioxide and 3-hexylthiophene based polymers. For this purpose a novel dibenzothiophen-S,S-dioxide and 3-hexylthiophene bearing, donor–acceptor–donor type monomer (THSO2) was synthesized through Stille cross-coupling reaction. THSO2 was electrochemically polymerized in tetrabutylammonium hexafluorophosphate- dichloromethane couple. Furthermore, THSO2 was subjected to electrochemical copolymerization in the presence of 3-hexylthiophene both potentiodynamically and potentiostatically. The resulting homopolymer and copolymers were characterized by means of cyclic voltammetry, FTIR, spectroelectrochemistry and kinetic studies. Depending on the synthesis conditions, the polymers exhibited optical band gaps ranging from 2.23 to 2.60 eV. Moreover, a highly soluble, fluorescent homopolymer was achieved using FeCl3 as the oxidant. The polymer provides several properties to be used in organic electronic applications.

► A novel monomer 3,7-bis-(4-hexyl-thiophen-2-yl)dibenzothiophene S,S-dioxide (THSO2) was synthesized.
► Solution processable, fluorescent, electrochromic, donor acceptor type dibenzothiophen-S,S-dioxide polymers was developed.
► Spectral behavior, coloration and band gap of the copolymers were controlled via variation of applied potential.