A thiophene-fused benzotriazole unit as a “π-bridge” in A-π-D-π-A type acceptor to achieve more balanced JSC and VOC for OSCs

Jiacheng Wang, Han Xu, Yiqun Xiao, Tengfei Li, Jiayu Wang, Kuan Liu, Xinhui Lu, Xiaowei Zhan, Xingguo Chen

Research output: Journal article publicationJournal articleAcademic researchpeer-review

9 Citations (Scopus)

Abstract

As known, to balance the open-circuit voltage (VOC) and short-circuit current density (JSC) is one of the effective strategies to improve the photovoltaic performances of OSCs. In this work, a thiophene-fused benzotriazole (BTAZT) unit acts as a “π-bridge” to build an acceptor (A3) with A-π-D-π-A structure for OSCs. Compared with a thiophene-fused benzothiadiazole (BTT) unit as a “π-bridge” in our previous acceptor (A2), BTAZT unit exhibits relatively weak electron-withdrawing ability that results in a significant uplift of LUMO energy level to favor for enhancement of VOC. Also, the fusion of a thiophene ring onto BTAZ unit strengthens the intramolecular charge transfer to maintain the relatively high JSC. Therefore, the PTB7-Th:A3 OSC device shows higher PCE of 11.0% with more balanced device parameters (VOC = 0.959 V, JSC = 17.30 mA cm−2, FF = 66.2%) as well as smaller energy loss (Eloss) of 0.63 eV than the PTB7-Th:A2 device with PCE of 8.20% (VOC = 0.701 V, JSC = 19.47 mA cm−2, FF = 60.1% and Eloss = 0.67 eV). This work indicates that the rational structural modification of a “π-bridge” for A-π-D-π-A type acceptor is an effective approach to achieve the balanced VOC and JSC for the OSCs.

Original languageEnglish
Article number105705
JournalOrganic Electronics
Volume82
DOIs
Publication statusPublished - Jul 2020

Keywords

  • A-π-D-π-A
  • Non-fullerene acceptor
  • Organic solar cells
  • Photovoltaic performances
  • Thiophene-fused benzotriazole

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Chemistry(all)
  • Biomaterials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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