High-Performance Solution-Deposited Ambipolar Organic Transistors Based on Terrylene Diimides

The thin film transistor characteristics of a soluble molecular semiconductor, terrylene tetra-carboxdiimide (TDI), a homologue of perylene ttetracarboxdiimide (PDI), have been investigated. In a bottom-gate device struucture with benzocyclobutene gate dielectric, n-type behavior with electron mobility of 1.1 x 10(-2) cm(2) V-1 s(-1) has been observed after thermal annealing. When applied in the top-gate structure with a polycyclohexylethylene--based gate dielectric, TDI devices exhibit ambipolar transport with electron and hole mobility of 7.2 x 10(-3) cm(2) V-1 s(-1) and 2.2 x 10(-3) cm(2) V-1 s(-1) respectively. The correlation between morphology and field-effect mobility was investigated by atomic force microscopy (AFM) and X-ray diffraction (XRD) studies. Spin-coated annealed TDI film crystallize in a terrace structure, and the molecules are packed in an edge-on structure, thus forming a favorable packing arrangement for charge transport in the plane of the film.