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.