Asymmetric Isomer Effects in Benzo[c][1,2,5]thiadiazole-Fused Nonacyclic Acceptors : Dielectric Constant and Molecular Crystallinity Control for Significantly Photovoltaic Performance Enhancement

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Wei Gao
  • Baobing Fan
  • Francis Lin
  • Rui Sun
  • Xinxin Xia
  • Jinhua Gao
  • Cheng Zhong
  • Xinhui Lu
  • Jie Min
  • Fujun Zhang

Detail(s)

Original languageEnglish
Article number2104369
Journal / PublicationAdvanced Functional Materials
Publication statusOnline published - 25 Jun 2021

Abstract

Herein, asymmetric isomer effects are systematically explored by designing and synthesizing two benzo[c][1,2,5]thiadiazole (BT)-fused nonacyclic electron acceptors. By changing from BP6T-4F to asymmetric ABP6T-4F, significantly enhanced dielectric constant and inhibited excessive molecular aggregation and unfavorable edge-on orientation could be achieved. The reduced exciton binding energy also facilitates a more efficient dissociation process in PM6:ABP6T-4F compared to PM6:BP6T-4F with the same energy offset. Moreover, the weaker crystallization behavior enables a significantly enhanced miscibility between PM6 and ABP6T-4F than that between PM6 and BP6T-4F, which leads to an optimized micromorphology with smooth surface, suitable domain size, and ordered ππ stacking. Organic solar cells (OSCs) based on PM6:ABP6T-4F achieve a 15.8% power conversion efficiency (PCE), which is remarkably higher than that of PM6:BP6T-4F-based OSCs (6.4%). Furthermore, ternary devices are also fabricated considering good compatibility between ABP6T-4F and CH1007 to deliver a PCE over 17%. This study reveals the effectiveness and great potential of asymmetric isomerization strategy in regulating molecular properties, which will provide guidance for the future design of non-fullerene acceptors.

Research Area(s)

  • asymmetric, isomer, non-fullerene acceptor, organic solar cells

Citation Format(s)

Asymmetric Isomer Effects in Benzo[c][1,2,5]thiadiazole-Fused Nonacyclic Acceptors : Dielectric Constant and Molecular Crystallinity Control for Significantly Photovoltaic Performance Enhancement. / Gao, Wei; Fan, Baobing; Qi, Feng; Lin, Francis; Sun, Rui; Xia, Xinxin; Gao, Jinhua; Zhong, Cheng; Lu, Xinhui; Min, Jie; Zhang, Fujun; Zhu, Zonglong; Luo, Jingdong; Jen, Alex K.-Y.

In: Advanced Functional Materials, 25.06.2021.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review