Hydrogen-bonded diketopyrrolopyrrole (DPP) pigments as organic semiconductors

Diketopyrrolopyrroles (DPPs) have recently gained attention as building-blocks for organic semiconducting polymers and small molecules, however the semiconducting properties of their hydrogen-bonded (H-bonded) pigment forms have not been explored. Herein we report on the performance of three archetypical H-bonded DPP pigments, which show ambipolar carrier mobilities in the range 0.01-0.06 cm 2 /V s in organic field-effect transis- tors. Their semiconducting properties are correlated with crystal structure, where an H- bonded crystal lattice supports close and relatively cofacial p-p stacking. To better under- stand transport in these systems, density functional theory calculations were carried out, indicating theoretical maximum ambipolar mobility values of � 0.3 cm 2 /V s. Based on these experimental and theoretical results, H-bonded DPPs represent a viable alternative to more established DPP-containing polymers and small molecules where H-bonding is blocked by N-alkylation.