Negative electric-field dependence of hole drift mobility for a molecular glass of tri(o-terphenyl-4-yl)amine

Charge transport in a novel molecular glass of tri(o-terphenyl-4-yl)amine has been studied. A negative electric-field dependence of hole drift mobility was found for the molecular glass. It is shown that a small diagonal disorder in terms of the disorder formalism is responsible for this phenomenon.