Comparison between the density-of-states of picene transistors measured in air and under vacuum

► Picene OTFTs on polystyrene dielectric present high field-effect mobilities in air (1.3 cm2 V−1 s−1). ► Density-of-states in the gap of picene was calculated by analysing the electrical characteristics. ► Narrow distributions of hole traps located at 0.28 and 0.42 eV from the HOMO level. ► Ionized oxygen molecules partly neutralize hole traps in devices exposed to air.