Correlation of Broad Absorption Band with Small Singlet-Triplet Energy Gap in Organic Photovoltaics

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Baobing Fan
  • Wei Gao
  • Rui Zhang
  • Werner Kaminsky
  • Lingxiao Tang
  • Francis R. Lin
  • Yiwen Wang
  • Qunping Fan
  • Wei Ma
  • Feng Gao

Detail(s)

Original languageEnglish
Article numbere202311559
Journal / PublicationAngewandte Chemie - International Edition
Volume62
Issue number46
Online published4 Oct 2023
Publication statusPublished - 13 Nov 2023

Abstract

Organic photovoltaics (OPV) are one of the most effective ways to harvest renewable solar energy, with the power conversion efficiency (PCE) of the devices soaring above 19 % when processed with halogenated solvents. The superior photocurrent of OPV over other emerging photovoltaics offers more opportunities to further improve the efficiency. Tailoring the absorption band of photoactive materials is an effective way to further enhance OPV photocurrent. However, the field has mostly been focusing on improving the near-infrared region photo-response, with the absorption shoulders in short-wavelength region (SWR) usually being neglected. Herein, by developing a series of non-fullerene acceptors (NFAs) with varied side-group conjugations, we observe an enhanced SWR absorption band with increased side-group conjugation length. The underpinning factors of how molecular structures and geometries improve SWR absorption are clearly elucidated through theoretical modelling and crystallography. Moreover, a clear relationship between the enhanced SWR absorption and reduced singlet-triplet energy gap is established, both of which are favorable for the OPV performance and can be tailored by rational structure design of NFAs. Finally, the rationally designed NFA, BO-TTBr, affords a decent PCE of 18.5 % when processed with a non-halogenated green solvent. © 2023 Wiley-VCH GmbH.

Research Area(s)

  • Broad Absorption Band, Non-Radiative Loss, Organic Solar Cell, Side-Group Conjugation, Singlet-Triplet Energy Gap

Citation Format(s)

Correlation of Broad Absorption Band with Small Singlet-Triplet Energy Gap in Organic Photovoltaics. / Fan, Baobing; Gao, Wei; Zhang, Rui et al.
In: Angewandte Chemie - International Edition, Vol. 62, No. 46, e202311559, 13.11.2023.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review