Hole transport in bis(4-N,N-diethylamino-2-methylphenyl)-4-methylphenylmethane

Abstract

By time-of-flight photocurrent techniques, hole transport has been investigated in vapor deposited films of the title compound. The measurements were made over a wide range of fields and temperatures which encompassed the glass transition temperature. The results are described within the framework of the disorder formalism due to Bässler and co-workers. The formalism is based on the assumption that transport occurs by hopping in a manifold of states subject to both energetic (diagonal) and positional (off-diagonal) disorder. In this paper, we describe (1) the field and temperature dependencies of the photocurrent transients, (2) the role of polymer dynamics on charge transport at temperatures above the glass transition temperature, and (3) the spectroscopy of interfacial hole states derived from an analysis of photocurrent transients in terms of computer simulations conducted under the premise of energy selective carrier injection into a Gaussian distribution of states.