Drastic change of molecular orientation in a thiazolothiazole copolymer by molecular-weight control and blending with PC61BM leads to high efficiencies in solar cells

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

doi:10.1002/adma.201103065

Drastic change of molecular orientation in a thiazolothiazole copolymer by molecular-weight control and blending with PC61BM leads to high efficiencies in solar cells

Adv Mater. 2012 Jan 17;24(3):425-30. doi: 10.1002/adma.201103065. Epub 2011 Dec 23.

Authors

Itaru Osaka¹, Masahiko Saito, Hiroki Mori, Tomoyuki Koganezawa, Kazuo Takimiya

Affiliation

¹ Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan; Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Chiyoda-ku 102-0075, Japan. [email protected].

PMID: 22213033
DOI: 10.1002/adma.201103065

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 (PC61BM) 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.

Keywords: bulk heterojunctions; molecular orientation; semiconducting polymers; solar cells; thiazolothiazole.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Electric Power Supplies*
Fullerenes / chemistry*
Molecular Weight
Polymers / chemistry*
Solar Energy*
Thiazoles / chemistry*

Substances

(6,6)-phenyl C61-butyric acid methyl ester
Fullerenes
Polymers
Thiazoles