Assessing intra- and inter-molecular charge transfer excitations in non-fullerene acceptors using electroabsorption spectroscopy.

Autor: Mahadevan S; Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR, PR China.; Centre of Super-Diamond and Advanced Films, City University of Hong Kong, Hong Kong SAR, PR China.; Hong Kong Institute of Clean Energy, City University of Hong Kong, Hong Kong SAR, PR China., Liu T; College of Physics and Electronic Information, Yunnan Normal University, Kunming, 650500, Yunnan, PR China., Pratik SM; Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, 85721-0041, USA., Li Y; Department of Physics, The Chinese University of Hong Kong, Hong Kong SAR, PR China., Ho HY; Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR, PR China.; Centre of Super-Diamond and Advanced Films, City University of Hong Kong, Hong Kong SAR, PR China.; Hong Kong Institute of Clean Energy, City University of Hong Kong, Hong Kong SAR, PR China., Ouyang S; Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR, PR China.; Centre of Super-Diamond and Advanced Films, City University of Hong Kong, Hong Kong SAR, PR China.; Hong Kong Institute of Clean Energy, City University of Hong Kong, Hong Kong SAR, PR China., Lu X; Department of Physics, The Chinese University of Hong Kong, Hong Kong SAR, PR China., Yip HL; Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR, PR China.; Centre of Super-Diamond and Advanced Films, City University of Hong Kong, Hong Kong SAR, PR China.; Hong Kong Institute of Clean Energy, City University of Hong Kong, Hong Kong SAR, PR China.; School of Energy and Environment, City University of Hong Kong, Hong Kong SAR, PR China., Chow PCY; Department of Mechanical Engineering, The University of Hong Kong, Pok Fu Lam, Hong Kong SAR, PR China., Brédas JL; Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, 85721-0041, USA., Coropceanu V; Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, 85721-0041, USA., So SK; Department of Physics and Institute of Advanced Materials, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, PR China., Tsang SW; Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR, PR China. saitsang@cityu.edu.hk.; Centre of Super-Diamond and Advanced Films, City University of Hong Kong, Hong Kong SAR, PR China. saitsang@cityu.edu.hk.; Hong Kong Institute of Clean Energy, City University of Hong Kong, Hong Kong SAR, PR China. saitsang@cityu.edu.hk.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2024 Mar 16; Vol. 15 (1), pp. 2393. Date of Electronic Publication: 2024 Mar 16.
DOI: 10.1038/s41467-024-46462-x
Abstrakt: Organic photovoltaic cells using Y6 non-fullerene acceptors have recently achieved high efficiency, and it was suggested to be attributed to the charge-transfer (CT) nature of the excitations in Y6 aggregates. Here, by combining electroabsorption spectroscopy measurements and electronic-structure calculations, we find that the charge-transfer character already exists in isolated Y6 molecules but is strongly increased when there is molecular aggregation. Surprisingly, it is found that the large enhanced charge transfer in clustered Y6 molecules is not due to an increase in excited-state dipole moment, Δμ, as observed in other organic systems, but due to a reduced polarizability change, Δp. It is proposed that such a strong charge-transfer character is promoted by the stabilization of the charge-transfer energy upon aggregation, as deduced from density functional theory and four-state model calculations. This work provides insight into the correlation between molecular electronic properties and charge-transfer characteristics in organic electronic materials.
(© 2024. The Author(s).)
Databáze: MEDLINE
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