In:
Angewandte Chemie, Wiley
Abstract:
Overcoming the trade‐off between short‐circuited current (Jsc) and open‐circuited voltage (Voc) is important to achieving high‐efficiency organic solar cells (OSCs). Previous works modulated energy gap between Frenkel local exciton (LE) and charge‐transfer (CT) exciton, which is served as driving force of exciton splitting. Differently, our current work focuses on modulation of LE‐CT excitonic coupling (tLE‐CT) via a simple but effective strategy that the 2‐chlorothiophene (2Cl‐Th) solvent is utilized in treatment of OSC active‐layer films. The results of our experimental measurements and theoretical simulations demonstrated that 2Cl‐Th solvent initiates the tighter intermolecular interactions with non‐fullerene acceptor in comparison with that of traditional chlorobenzene solvent, thus suppressing the acceptor’s over‐aggregation and retarding the acceptor crystallization with reduced trap. Importantly, the resulted shorter distances between donor and acceptor molecules in the 2Cl‐Th treated blend efficiently strengthen tLE‐CT, which not only promotes the exciton splitting but also reduces non‐radiative recombination. The champion efficiencies of 19.8% (small‐area) with a superior operational reliability (T80: 586 hours) and 17.0% (large‐area) were yielded in 2Cl‐Th treated cells. This work provided a new insight into modulating the exciton dynamics to overcome the trade‐off between Jsc and Voc, which can productively promote the development of OSC field.
Type of Medium:
Online Resource
ISSN:
0044-8249
,
1521-3757
DOI:
10.1002/ange.202411512
Language:
English
Publisher:
Wiley
Publication Date:
2024
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