2,1,3-Benzooxadiazole, thiophene and benzodithiophene based random copolymers for organic photovoltaics: thiophene versus thieno[3,2-b]thiophene as pi-conjugated linkers

Goker S., HIZALAN G., AKTAS E., KUTKAN S., ÇIRPAN A., TOPPARE L.

NEW JOURNAL OF CHEMISTRY, vol.40, no.12, pp.10455-10464, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 40 Issue: 12
  • Publication Date: 2016
  • Doi Number: 10.1039/c6nj02469f
  • Journal Name: NEW JOURNAL OF CHEMISTRY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.10455-10464
  • Middle East Technical University Affiliated: Yes

Abstract

Three conjugated random copolymers comprising benzodithiophene and thiophene as the donor units and benzooxadiazole as the acceptor unit, spaced with thiophene and thieno[3,2-b]thiophene pi-bridges, were designed and synthesized. The effects of different linkers on the optical and electrochemical properties were investigated. The polymer containing a thieno[3,2-b]thiophene pi-bridge revealed a red shifted absorption compared to its thiophene analogue. Morphological and photovoltaic properties of a polymer:fullerene blend film were investigated. The blend of one of the random copolymers (P-2) and PC71BM ([6,6]-phenyl-C-71-butyric acid methyl ester) revealed a photovoltaic performance efficiency of 5.17% due to the high short-circuit current density and fill factor.