Direct Preparation of Mixed Self-assembled Monolayers Based on Common-substructure-tailored Phosphonic Acids for Fine Control of Surface Wettability

An anthracene-terminated self-assembled monolayer (SAM) material, ANT-PA, was synthesized, which contains an anchor unit corresponding to octadecylphosphonic acid, C18-PA itself. Thanks to the common substructure of ANT-PA and C18-PA, mixing the two materials allows forming uniform mixed SAMs, offering surface wettabilities finely tunable within the range of those for the single-component SAMs of each ANT-PA and C18-PA. This feature is quite effective for realizing the optimal solution-coating conditions for organic semiconductor inks, leading to improved thin-film transistor (TFT) properties.