TITLE:
Effect of Side Chain of Oligothiophene Derivatives on Bulk Heterojunction Structure in Organic Photovoltaic Devices
AUTHORS:
Kenichi Sasaki, Yosei Shibata, Ming Lu, Yuji Yoshida, Reiko Azumi, Yasukiyo Ueda
KEYWORDS:
Organic Photovoltaic Cells; Sexthiophene; Bulk Heterojunction; Morphology
JOURNAL NAME:
Advances in Materials Physics and Chemistry,
Vol.3 No.2,
June
19,
2013
ABSTRACT: The effect of the molecular structure on
photovoltaic performance was investigated by comparing two types of active
layers. One is an active layer formed by sexithiophene (6T) and C60 molecules
which don’t have side chains. Another one is an active layer formed by a,ω-bis(2-hexyldecyl)sexithiophene (BHD6T)
and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) molecules
which have side chains. The 6T:C60 active layer exhibited an excessive
crystallization of 6T, which led to the low photovoltaic performance. In the
BHD6T:PCBM active layer, the crystallization of BHD6T was suppressed. The crystallization
of BHD6T was also easily controlled by thermal annealing, which led to improved
photovoltaic performance.