Low-bandgap polymers with quinoid unit as π bridge for high-performance solar cells
Artikel i vetenskaplig tidskrift, 2020

To construct efficient low band gap polymers, increasing the Quinone structure of the polymer backbone could be one desirable strategy. In this work, two D–Q–A–Q polymers P1 and P2 were designed and synthesized with thiophenopyrrole diketone (TPD) and benzothiadiazole (BT) unit as the core and ester linked thieno[3,4-b]thiophene (TT) segment as π-bridging, and the main focus is to make a comparative analysis of different cores in the influence of the optical, electrochemical, photochemical and morphological properties. Compared with the reported PBDTT EH –TBTT HD−i , P1 exhibited the decreased HOMO energy level of −5.38 eV and lower bandgap of 1.48 eV. Furthermore, when replaced with BT core, P2 showed a red-shifted absorption profile of polymer but with up-shifted HOMO energy level. When fabricated the photovoltaic devices in conventional structure, just as expected, the introduction of ester substituent made an obvious increase of V OC from 0.63 to 0.74 V for P1. Besides, due to the deep HOMO energy level, higher hole mobility and excellent phase separation with PC 71 BM, a superior photovoltaic performance (PCE = 7.13%) was obtained with a short-circuit current density (J SC ) of 14.9 mA/cm 2 , significantly higher than that of P2 (PCE = 2.23%). Generally, this study highlights that the strategy of inserting quinoid moieties into D–A polymers could be optional in LBG-polymers design and presents the importance and comparison of potentially competent core groups.

Quinone structure

Low bandgap polymer


Side-chain engineering


Bilal Shahid

Chinese Academy of Sciences

Xiyue Yuan

Chinese Academy of Sciences

Qian Wang

Chinese Academy of Sciences

Di Zhou

Chinese Academy of Sciences

Ergang Wang

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Ergang Wang Group

Xichang Bao

Chinese Academy of Sciences

D. Q. Zhu

Chinese Academy of Sciences

R. Yang

Chinese Academy of Sciences

Journal of Energy Chemistry

2095-4956 (ISSN)

Vol. 40 2020 180-187



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