CF3-Terminated Side Chain Enables Efficiencies Surpassing 18.2% and 16.1% in Small- and Large-Scale Manufacturing of Organic Solar Cells

Many studies have proven the significant roles of side chains far beyond being the solubilizing groups as well as the interesting merits of fluorination on π-backbones in the intrinsic properties and device performances of organic semiconductors. Considering the integration of the two features, we herein introduce a 4,4,4-trifluorobutyl (CF3-terminated) side chain into a 2H-1,2,3-benzotriazole-core-based acceptor–donor–acceptor–donor–acceptor-type nonfullerene acceptor (NFA) named YCF3 and demonstrate its effectiveness in optoelectronic, morphological, and photovoltaic properties. Comparative experimental and theoretical studies confirmed the unique features of YCF3 (e.g., red-shifted film absorption, better absorptivity, finely adjusted energies, and higher mobility) associated with its enhanced crystalline nature, compared with its analogous NFA with an n-butyl side chain named YCH3. The best power conversion efficiency (PCE) of 18.21% is achieved in a YCF3-based binary organic solar cell (OSC) together with good heat and light stability. Moreover, a YCF3-based OSC presents a remarkable PCE of 16.11% in an inverted-structure large-area device.