Functionalized soluble triethylsilylethynyl anthradithiophenes (TESADTs) for organic electronic devices

Four new solution-processable triethylsilylethynyl anthradithiophene-(TESADT) based organic semiconductors, end-capped with phenyl (DP-; 1), thien-2-yl (DT-; 2), thienothien-2-yl (DTT-; 3), and perfluorophenyl (DFP-; 4) groups have been synthesized, characterized, and incorporated in organic thin-film transistors (OTFTs) and organic photovoltaics (OPVs). For the fabrication of solution-processed OTFT, thin films of all four compounds have been fabricated via a solution process of solution-shearing (SS), droplet-pinned crystallization (DPC), and drop-casting (DC). Among various solution-processing methods, solution-shearing produced TFTs the highest electrical performance. Thin films of compound 1 formed via the SS method exhibited p-channel characteristics, with hole mobilities as high as ∼0.034 cm²V^-1s^-1. The film morphologies and microstructures of these compounds have been characterized by atomic force microscopy and X-ray diffraction to rationalize device performance trends. Furthermore, DP-TESADT (1) and DFP-TESADT (4) has been employed for the fabrication of OPVs. Especially, pseudo-bilayer polymer solar cells based on an underlayer of poly(3-hexylthiophene) (P3HT) doped with 2.4% DP-TESADT and 9.1% DFP-TESADT and an upper layer of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) achieved power conversion efficiency up to 2.1%.