Asymmetric simple unfused acceptor enabling over 12% efficiency organic solar cells

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 412; p. 128770
• Main Authors: Cao, Jinru, Qu, Shenya, Yang, Linqiang, Wang, Hongtao, Du, Fuqiang, Yu, Jiangsheng, Tang, Weihua
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.05.2021
• Subjects: Core engineering; dithieno[3,2-b:2′,3′-d]pyrrole; Framework-property relationship; Organic solar cells; Simple acceptors; Unfused acceptors; Core engineering; Simple acceptors; Unfused acceptors; Organic solar cells; Framework-property relationship; dithieno[3,2-b:2′,3′-d]pyrrole
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.128770

Framework-property relationship in unfused acceptors is systematically investigated, and three unfused acceptors with diverse frameworks (DBT-4F, DBD-4F and DBTD-4F) are developed. The benzen-cored asymmetric DBT-4F exhibits better miscibility with PBDB-T to present homogenous fibrous phase separation in the blend. They afford a champion efficiency of 12.14%, among the highest for unfused acceptors based OSCs reported so far. The work demonstrates DTP based unfused acceptors adopting A-D1-D-D2-A framework have great potential for developing high-efficient OSCs via rational molecular design. [Display omitted] •Efficient unfused acceptor with dithieno[3,2-b:2′,3′-d]pyrrole.•Optimal phase-separation and structural order achieved in the blend with PBDB-T;•A champion PCE of 12.14% for unfused acceptor based organic solar cells. High photovoltaic performance with cost-effective material synthesis and device fabrication are the prerequisite for commercialization of organic solar cells (OSCs). Herein, we conduct a systematic structure–property correlation study on unfused acceptors adopting different frameworks. Dithieno[3,2-b:2′,3′-d]pyrrole (DTP) based A-D1-D-D2-A asymmetric acceptor (DBT-4F) has been screened as a promising acceptor for high-efficient OSCs. Three DTP-based unfused acceptors display strong near-infrared absorption with narrow optical band gap (Egopt < 1.45 eV). Blends of DBT-4F with PBDB-T contribute a champion power conversion efficiency (PCE) of 12.14% due to better miscibility to form homogenous fibrous phase separation. To the best of our knowledge, the PCE is among the highest values for unfused acceptor based binary OSCs in the literature. The excellent performance of DBT-4F is revealed with more efficient photon-harvesting, higher and more balanced charge transport, and less charge recombination in the blends. Our work manifests the great potential of DTP based asymmetric unfused acceptor for developing high-efficient OSCs via rational molecular design.