Drastic change of molecular orientation in a thiazolothiazole copolymer by molecular-weight control and blending with PC 61BM leads to high efficiencies in solar cells

Itaru Osaka, Masahiko Saito, Hiroki Mori, Tomoyuki Koganezawa, Kazuo Takimiya

Research output: Contribution to journalArticle

134 Citations (Scopus)

Abstract

A thiazolothiazole-thiophene copolymer is examined as the active material in bulk heterojunction (BHJ) solar cells. By optimizing the molecular weight, the polymer-based cells exhibit power conversion efficiencies as high as 5.7%. The increase in molecular weight improves the orientational order, and blending with phenyl-C61-butyric acid methyl ester (PC 61BM) changes the orientational motif from edge-on to face-on, which accounts for the trend in photovoltaic performances. These results might give new insight into the structure-property relationships in BHJ solar cells.

Original languageEnglish
Pages (from-to)425-430
Number of pages6
JournalAdvanced Materials
Volume24
Issue number3
DOIs
Publication statusPublished - Jan 17 2012

Keywords

  • bulk heterojunctions
  • molecular orientation
  • semiconducting polymers
  • solar cells
  • thiazolothiazole

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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