Over 18% Efficiency from Halogen-Free Solvent-Processed Polymer Solar Cells Enabled by Asymmetric Small Molecule Acceptors with Fluoro-Thienyl Extended Terminal
Journal article, 2025
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···S interaction, other than the commonly believed strong hydrogen bonding of F···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.
power conversion efficiency
molecular conformation
polymer solar cell
non-halogen solvent
non-fullerene acceptor
Author
Jingnan Wu
Aalborg University
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Fengbo Sun
Shandong University
Xinxin Xia
Shandong University
Chinese University of Hong Kong
Leandro Rezende Franco
Karlstad University
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Qiaonan Chen
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Yúang Fu
Chinese University of Hong Kong
Rafael B. Ribeiro
Uppsala University
University of Sao Paulo (USP)
Xinhui Lu
Chinese University of Hong Kong
C. Moyses Araujo
Karlstad University
Uppsala University
Xunchang Wang
Jianghan University
Renqiang Yang
Jianghan University
Xia Guo
Shandong University
Donghong Yu
Sino-Danish Center for Education and Research Denmark
Aalborg University
Maojie Zhang
Shandong University
Ergang Wang
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Advanced Functional Materials
1616-301X (ISSN) 16163028 (eISSN)
Vol. In PressAlkyl chain linked conjugated polymers for stable polymer solar cells
Swedish Research Council (VR) (2019-04683), 2020-01-01 -- 2023-12-31.
Subject Categories (SSIF 2025)
Materials Chemistry
Infrastructure
Chalmers e-Commons (incl. C3SE, 2020-)
DOI
10.1002/adfm.202423137