Over 18% Efficiency from Halogen-Free Solvent-Processed Polymer Solar Cells Enabled by Asymmetric Small Molecule Acceptors with Fluoro-Thienyl Extended TerminalShow others and affiliations
2025 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, article id 2423137Article in journal (Refereed) Published
Abstract [en]
The potential impact of end-group (EG) in non-fullerene acceptor (NFA) on enabling green solvent-processable polymer solar cells (PSCs) remains underexplored, offering opportunities for advancements in environmentally friendly PSC development. Herein, the EG of 1 ',1 '-dicyanomethylene-4-fluoro-5-thienyl-3-indanone (IC-FT) is developed by modifying the state-of-the-art of Y6 derivative NFA, BTP-4F, resulting in two novel NFAs, namely BTP-FT and BTP-2FT. Distinctively, this study reveals that it is the noncovalent F<middle dot><middle dot><middle dot>S interaction, other than the commonly believed strong hydrogen bonding of F<middle dot><middle dot><middle dot>H that plays a key role in determining the final molecular conformation, as confirmed by means of 2D NMR study and Gibbs free energy calculations. The asymmetric BTP-FT possesses an upshifted lowest unoccupied molecular orbital level and enhances solubility in toluene. Consequently, it can mitigate phase separation, promote the formation of nanofibrillar morphology, facilitate exciton dissociation, and ultimately enhance the performance of the PSCs, achieving a high open circuit voltage of 0.900 V and a power conversion efficiency (PCE) of 17.56%. Furthermore, the ternary blend PM6:BTP-FT:BTP-4F achieves an enhance PCE of 18.39% in devices processed from toluene. This study offers a novel perspective on NFA design for high-efficiency and eco-friendly processable PSCs by enriching the array of electron-withdrawing EGs on NFA molecules.
Place, publisher, year, edition, pages
John Wiley & Sons, 2025. article id 2423137
Keywords [en]
molecular conformation, non-fullerene acceptor, non-halogen solvent, polymer solar cell, power conversion efficiency
National Category
Materials Chemistry
Research subject
Physics; Materials Science
Identifiers
URN: urn:nbn:se:kau:diva-103195DOI: 10.1002/adfm.202423137ISI: 001398790500001Scopus ID: 2-s2.0-85215528687OAI: oai:DiVA.org:kau-103195DiVA, id: diva2:1938501
Funder
Swedish Research Council, 2019-04683, 2020-05223, 2022-06725, 2018-05973Knut and Alice Wallenberg Foundation, 2022.0192, WISESwedish Energy Agency, P2021-90067, 45420-12025-02-182025-02-182025-02-18Bibliographically approved