Precise Synthesis of Fused Decacyclic Electron Acceptor Isomers for Organic Solar Cells

Two intermediates (dimethyl 3,7-dibromonaphthalene-2,6-dicarboxylate and dimethyl 1,5-dibromonaphthalene-2,6-dicarboxylate) are synthesized to realize the isomerization of naphthalene-based decacyclic fused-ring electron acceptors FTIC1 and FTIC2. The linear-shaped FTIC1 and nonlinear-shaped FTIC2 share the same terminal groups and side chains but different isomeric central cores. They share similar light absorption spectra in the 500-850 nm region and energy bandgaps, although FTIC2 shows a higher maximum molar absorptivity and electron mobility than FTIC1. Compared with the blend film of PM6/FTIC1, the active layer film of PM6/FTIC2 exhibits higher and more balanced hole and electron mobilities due to the influence of the nanoscale morphology. In terms of the photovoltaic performance of the organic solar cells, the FTIC2-based devices afford a higher efficiency of 11.7% with short-circuit current density (J(SC)) of 17.2 mA cm(-2) than FTIC1-based devices (8.98%).