Department of Chemistry
Synthesis of a novel low-bandgap polymer based on a ladder-type Heptacyclic arene consisting of outer thieno[3,2-b]thiophene units for efficient photovoltaic application
A novel conjugated polymer PIDTT-quinoxaline (Qx) based on the coplanar thieno[3,2-b]thiophene-phenylene-thieno[3,2-b]thiophene structure is synthesized and evaluated as an electron-donor material for bulk-heterojunction polymer solar cells (BHJ PSCs). The absorption spectra, electrochemical, charge transport, and film morphology properties as well as theoretical modeling of PIDTT-Qx are investigated to understand its intrinsic structure-property relationship. As expected, this polymer with an extended π-conjugated backbone exhibits a narrow-bandgap and board absorption spectrum for enhanced light harvesting. BHJ PSCs (ITO/PEDOT:PSS/polymer:PC71BM/interlayer/ Al) afford a maximum power conversion efficiency of 5.05% with an open-circuit voltage of 0.84 V, a short-circuit current density of 11.26 mA cm-2, and a fill factor of 53.4%. These results demonstrate the potential of PIDTT-Qx as an efficient electron-donor material for BHJ PSCs. A novel conjugated polymer PIDTT-quinoxaline (Qx) based on the coplanar thieno[3,2-b]thiophene-phenylene- thieno[3,2-b]thiophene structure is synthesized as the electron-donor material for bulk-heterojunction polymer solar cells. The forced planarization structure with heptacyclic rings can further facilitate effective π-electron delocalization, extend effective conjugation length of the backbone, and intensely reduce the target polymer's bandgap. Efficient bulk-heterojunction polymer solar cells with PCE of about 5.1% are fabricated. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
charge transport, forced planarization, low-bandgap conjugated polymers, polymer solar cells, structure-property relations
Source Publication Title
Macromolecular Rapid Communications
Link to Publisher's Edition
Xu, Xiaofeng, Ping Cai, Yong Lu, Ng Siu Choon, Junwu Chen, Beng S. Ong, and Xiao Hu. "Synthesis of a novel low-bandgap polymer based on a ladder-type Heptacyclic arene consisting of outer thieno[3,2-b]thiophene units for efficient photovoltaic application." Macromolecular Rapid Communications 34.8 (2013): 681-688.