Comprehensive study of pyrido[3, 4‐b]pyrazine‐based D–π–a copolymer for efficient polymer solar cells. Issue 12 (29th January 2016) - Wu, Yu‐Qi
ABSTRACT: Two D–π–A copolymers, based on the benzo[1, 2‐ b :4, 5‐ b ′]‐dithiophene (BDT) as a donor unit and benzo‐quinoxaline (BQ) or pyrido‐quinoxaline (PQ) analog as an acceptor (PBDT‐TBQ and PBDT‐TPQ), were designed and synthesized as a p‐type material for bulk heterojunction (BHJ) photovoltaic cells. When compared with the PBDT‐TBQ polymer, PBDT‐TPQ exhibits stronger intramolecular charge transfer, showing a broad absorption coverage at the red region and narrower optical bandgap of 1.69 eV with a relatively low‐lying HOMO energy level at −5.24 eV. The experimental data show that the exciton dissociation efficiency of PBDT‐TPQ:PC71 BM blend is better than that in the PBDT‐TBQ:PC71 BM blend, which can explain that the IPCE spectra of the PBDT‐TPQ‐based solar cell were higher than that of the PBDT‐TBQ‐based solar cell. The maximum efficiency of PBDT‐TPQ‐based device reaches 4.40% which is much higher than 2.45% of PBDT‐TBQ, indicating that PQ unit is a promising electron‐acceptor moiety for BHJ solar cells. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2016, 54, 1822–1833 Abstract : A D‐π‐A copolymer containing a strong electron acceptor unit of pyrido‐quinoxaline (PQ) in comparison with the benzo‐quinoxaline (BQ)‐based analog was proved to be an efficient p‐type polymer for solution‐processed organic photovoltaics.