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The Importance of End Groups for Solution‐Processed Small‐Molecule Bulk‐Heterojunction Photovoltaic Cells
Author(s) -
Duan Ruomeng,
Cui Yong,
Zhao Yanfei,
Li Chen,
Chen Long,
Hou Jianhui,
Wagner Manfred,
Baumgarten Martin,
He Chang,
Müllen Klaus
Publication year - 2016
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201501626
Subject(s) - thiophene , alkyl , photovoltaic system , organic solar cell , conjugated system , solubility , molecule , materials science , small molecule , acceptor , polymer solar cell , energy conversion efficiency , polymer , computational chemistry , photochemistry , chemistry , organic chemistry , optoelectronics , ecology , biochemistry , physics , condensed matter physics , biology
End groups in small‐molecule photovoltaic materials are important owing to their strong influence on molecular stability, solubility, energy levels, and aggregation behaviors. In this work, a series of donor–acceptor pentads (D 2 –A–D 1 –A–D 2 ) were designed and synthesized, aiming to investigate the effect of the end groups on the materials properties and photovoltaic device performance. These molecules share identical central A–D 1 –A triads (with benzodithiophene as D 1 and 6‐carbonyl‐thieno[3,4‐ b ]thiophene as A), but with various D 2 end groups composed of alkyl‐substituted thiophene (T), thieno[3,2‐ b ]thiophene (TT), and 2,2′‐bithiophene (BT). The results indicate a relationship between conjugated segment/alkyl chain length of the end groups and the photovoltaic performance, which contributes to the evolving molecular design principles for high efficiency organic solar cells.