1,1′-Biaceanthrylene and 2,2′-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2′-biaceanthrylene) or inward (1,1′-biaceanthrylene), and the optical and electronic properties were compared. Only the planar 2,2′-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer. Organic field effect transistors based on 2,2′-biaceanthrylene were prepared and were found to operate in the hole transport regime with an average charge carrier mobilities of 1.8 × 10–4 cm2 V–1 s–1.本研究表明，连接于两个五元环之间的多环芳烃（polycyclic aromatic hydrocarbon, PAH）发色团可形成平面化结构，其光学带隙与氧化还原电位均有所降低。我们将两个醋蒽烯（aceanthrylene）发色团构建为二聚体模型体系，根据发色团的排布方向分为向外伸展型（2,2′-二醋蒽烯）与向内凹陷型（1,1′-二醋蒽烯），并对二者的光电性质进行了对比分析。相较于醋蒽烯单体，仅平面化的2,2′-二醋蒽烯体系表现出显著的光学带隙与氧化还原电位降幅，其中光学带隙降低1 eV。我们制备了基于2,2′-二醋蒽烯的有机场效应晶体管（Organic Field-Effect Transistor, OFET），测试结果表明其工作于空穴传输机制，平均载流子迁移率为1.8 × 10–4 cm² V–1 s–1。