Synthesis of new donor-acceptor polymers containing thiadiazoloquinoxaline and pyrazinoquinoxaline moieties: low-band gap, high optical contrast, and almost black colored materials


Unver E. K. , Tarkuc S., BARAN D., TANYELİ C., Toppare L.

TETRAHEDRON LETTERS, vol.52, no.21, pp.2725-2729, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 52 Issue: 21
  • Publication Date: 2011
  • Doi Number: 10.1016/j.tetlet.2011.03.078
  • Journal Name: TETRAHEDRON LETTERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.2725-2729
  • Keywords: Donor-acceptor polymers, Low-band gap polymers, Thiadiazoloquinoxaline, Pyrazinoquinoxaline, SOLAR-CELLS, CONJUGATED POLYMERS, COPOLYMERS, DEVICES, ELECTROLUMINESCENCE, SEMICONDUCTORS, POLYFLUORENES, DERIVATIVES, TRANSISTORS, THIOPHENES
  • Middle East Technical University Affiliated: Yes

Abstract

Two low band gap conjugated polymers, poly[4,9-bis(4-hexylthien-2-yl)-6,7-di(thien-2-yl)-[1,2,5]thiadiazolo[3,4-g]quinoxaline] (PHTTQ) and poly[5,10-bis(4-hexylthien-2-yl)-2,3,7,8-tetra(thien-2-yl)pyrazino[2,3-g]quinoxaline] (PHTPQ), consisting of alternating electron-rich 3-hexylthiophene and electron-deficient 6,7-di(thien-2-yl)-[1,2,5]thiadiazolo[3,4-g]quinoxaline (TTQ) and 2,3,7,8-tetra(thien-2-yl)-2,3-dihydropyrazino[2,3-g]quinoxaline (TPQ) units were synthesized electrochemically. The structures of the pi-conjugated monomers were tailored using thiophene as the pendant group on the acceptor units (TTQ and TPQ). The electrochemical and optical properties of the polymers were investigated by cyclic voltammetry and UV-vis-NIR spectroscopy. The absorption spectra of PHTPQ revealing a 1.0 eV band gap, exhibited three maxima at 352 nm, 535 nm, and 750 nm. Consequently, its absorption spectra cover the region between 400 and 800 nm, which make the polymer almost black in appearance. PHTTQ shows lambda(max) value of 820 nm and a band gap of 0.8 eV which is very low among other [1,2,5]thiadiazolo[3,4-g]quinoxaline-containing donor-acceptor type polymers. (C) 2011 Elsevier Ltd. All rights reserved.