Synthesis and electropolymerization of donor-acceptor-donor type monomers based on azobenzene-substituted thieno[3,4-c]pyrrole-4,6-dione acceptors

ÇAKAL D., CİHANER A., ÖNAL A. M.

ELECTROCHIMICA ACTA, vol.398, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 398
  • Publication Date: 2021
  • Doi Number: 10.1016/j.electacta.2021.139325
  • Journal Name: ELECTROCHIMICA ACTA
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Communication Abstracts, INSPEC, Metadex, Civil Engineering Abstracts
  • Keywords: Azobenzene, D-A-D monomers and polymer, Photo-isomerization, Ambipolar conjugated polymer, SOLAR-CELLS, ELECTROCHROMIC POLYMER, CONDUCTING POLYMERS, CONJUGATED POLYMERS, HIGH CRYSTALLINITY, CHARGE-TRANSPORT, HIGH-PERFORMANCE, MOLECULES, BENZOTHIADIAZOLE, COPOLYMERS
  • Middle East Technical University Affiliated: Yes

Abstract

By using donor-acceptor-donor approach, a new series of photo responsive and electroactive trimeric monomers, namely (E)-5-(4-(phenyldiazenyl)phenyl)-1,3-di(thiophen-2-yl)-4H-thieno[3,4- c]pyrrole-4,6(5H)-dione (T-2-AB ), (E)-1,3-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-5-(4-(phenyldiazenyl)phenyl)- 4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (E-2-AB ) and (E)-1,3-bis(3,3-didecyl-3,4-dihydro-2H-thieno[3,4- b][1,4]dioxepin-6-yl)-5-(4-(phenyldiazenyl)phenyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (P-2-AB ), was synthesized and characterized. The oxidation potential of the monomers was controlled by the strength of donor units and the following trend was observed for them: Eox (T-2-AB ) > E-ox (P-2-AB ) > E-ox (E-2-AB ). Also, a similar behavior was observed for their band gap values: 2.53 eV for T-2-AB , 2.18 eV for E-2-AB and 2.28 eV for P-2-AB . The monomers were polymerized successfully via electrochemical methods in order to give electrochromic ambipolar conjugated polymers bearing narrow optical band gaps: 1.71 eV, 1.54 eV and 1.68 eV for PT2-AB, PE2-AB , and PP2-AB, respectively. Also, the polymer films are stable and robust. Moreover, the three monomers and soluble PP(2-)AB polymer exhibited trans to cis photo-isomerization upon irradiation with UV light. In addition, the photoluminescence intensity of the monomers in toluene was found to decrease with increasing acid concentration, which makes them potential candidates to be amenable as pH sensors. (C) 2021 Elsevier Ltd. All rights reserved.