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D-A(1)-D-A(2) Copolymers with Extended Donor Segments for Efficient Polymer Solar Cells

Qiang Tao (Institutionen för kemi och kemiteknik, Polymerteknologi) ; Y. X. Xia ; Xiaofeng Xu (Institutionen för kemi och kemiteknik, Polymerteknologi) ; S. Hedstrom ; Olof Bäcke (Institutionen för teknisk fysik, Eva Olsson Group ) ; David James (Institutionen för kemi och kemiteknik, Polymerteknologi) ; P. Persson ; Eva Olsson (Institutionen för teknisk fysik, Eva Olsson Group ) ; O. Inganas ; L. T. Hou ; W. G. Zhu ; Ergang Wang (Institutionen för kemi och kemiteknik, Polymerteknologi)
Macromolecules (0024-9297). Vol. 48 (2015), 4, p. 1009-1016.
[Artikel, refereegranskad vetenskaplig]

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.



Denna post skapades 2015-04-13. Senast ändrad 2015-07-07.
CPL Pubid: 215161

 

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Institutioner (Chalmers)

Institutionen för kemi och kemiteknik, Polymerteknologi
Institutionen för teknisk fysik, Eva Olsson Group (2012-2015)

Ämnesområden

Polymerteknologi
Energisystem

Chalmers infrastruktur

 


Projekt

Denna publikation är ett resultat av följande projekt:


SUstainable Novel FLexible Organic Watts Efficiently Reliable (SUNFLOWER) (EC/FP7/287594)