Effect of aromatic substituents on the H-bonded assembly of diketopyrrolopyrroles at solid-liquid interfaces.

Hydrogen-bonded (H-bonded) self-assembly is a suitable approach for tailoring the solid-state packing and properties of organic semiconductors. Here we studied the H-bonded self-assembly of an important class of organic semiconductors, diketopyrrolopyrrole (DPP) derivatives, diselenophenylDPP (DSeDPP), dithiazolylDPP (DTzDPP), and dithienothiophenylDPP (DTTDPP), at solid-liquid interfaces using scanning tunneling microscopy (STM) and density functional theory (DFT). At the 1-octanoic acid/highly ordered pyrolytic graphite (HOPG) interface, DSeDPP and DTzDPP either co-assemble with the solvent