Ambipolar Transistor Properties of Metal Complexes Derived from 1,2-Phenylenediamines

Nickel complexes of 1,2-phenylenediamine show ambipolar transistor properties on tetratetracontane. Palladium, platinum, and cobalt analogues show similar transistor properties, and particularly the palladium complex exhibits considerably improved performance, which is satisfactorily reproduced by the calculated mobility. By using methyl- and fluoro-substituted 1,2-phenylenediamines, we can observe a gradual shift from mainly hole transporting to mainly electron transporting characteristics with the systematical shift of the threshold voltages. The small energy gaps of the metal complexes are reflected in the comparatively sharp charge neutrality point as a small-molecule material.