In this work, we show that hydrogen bond interactions, in addition to directing supramolecular order,
can have an intriguing effect on the molecular and electronic properties of DPP derivatives, facilitating
redox processes in the solid state. As a result, charge carrier formation can be enhanced in devices,
contributing to the improvement of electrical performances of two exceptionally small molecular
semiconductors based on a thiophene-capped diketopyrrolopyrrole (DPP) as the electroactive component
and amide groups as hydrogen-bonding units. Two different topologies of the amide groups
were explored, C-centered and N-centered (HDPPBA-C and HDPPBA-N, respectively), and the results
were compared to the HDPPH molecule with no amide groups. Spectroelectrochemical experiments, in
conjunction with vibrational spectroscopies and DFT calculations, demonstrate that hydrogen bond
formation promotes modifications on the effective conjugation length of the studied semiconductors,
which may facilitate the generation of free charge carriers in organic field effect transistors (OFETs).
These results open a new strategy towards the simple design of organic semiconductors and control
over their morphological and electrical properties by simple hydrogen bond formation.
