D-A(1)-D-A(2) Copolymers with Extended Donor Segments for Efficient Polymer Solar Cells
Artikel i vetenskaplig tidskrift, 2015

Typically a donor-acceptor (D-A) design strategy is used for engineering the bandgap of polymers for solar cells. However, in this work, a series of alternating D-A(1-)D-A(2) copolymers PnTQTI(F) were synthesized and characterized with oligothiophenes (nT, n = 1, 2, 3) as the donor and two electron-deficient moieties, quinoxaline and isoindigo, as the acceptors in the repeating unit. We have studied the influence of the donor segments with different numbers of thiophene units and the effect of the addition of fluorine to the quinoxaline unit of the D-A(1)-D-A(2) polymers. The photophysical, electrochemical, and photovoltaic properties of the polymers were examined via a range of techniques and related to theoretical simulations. On increasing the length of the donor thiophene units, broader absorption spectra were observed in addition to a sequential increase in HOMO levels, while the LUMO levels displayed very small variations. The addition of fluorine to the quinoxaline unit not only decreased the HOMO levels of the resulting polymers but also enhanced the absorption coefficients. A superior photovoltaic performance was observed for the P3TQTI-F-based device with a power conversion efficiency (PCE) of 7.0%, which is the highest efficiency for alternating D-A(1)-D-A(2) polymers reported to date. The structureproperty correlations of the PnTQTI(F) polymers demonstrate that varying of the length of the donor segments is a valuable method for designing high-performance D-A(1)-D-A(2) copolymers and highlight the promising nature of D-A(1)-D-A(2) copolymers for efficient bulk-heterojunction solar cells.

Författare

Qiang Tao

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Polymerteknologi

Y. X. Xia

Chalmers University of Technology

Xiaofeng Xu

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Polymerteknologi

Svante Hedström

Lunds universitet

Olof Bäcke

Chalmers, Teknisk fysik, Eva Olsson Group

David James

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Polymerteknologi

P. Persson

Lunds universitet

Eva Olsson

Chalmers, Teknisk fysik, Eva Olsson Group

Olle Inganäs

Linköpings universitet

Lintao Hou

Jinan University

W. G. Zhu

XiangTan University

Ergang Wang

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Polymerteknologi

Macromolecules

0024-9297 (ISSN) 1520-5835 (eISSN)

Vol. 48 1009-1016

SUstainable Novel FLexible Organic Watts Efficiently Reliable (SUNFLOWER)

Europeiska kommissionen (FP7), 2011-10-01 -- 2016-03-31.

Ämneskategorier

Polymerteknologi

Energisystem

DOI

10.1021/ma502186g