Hole Transport in a Vapor Deposited Phenylenediamine Molecular Glass

Hole mobilities have been measured in vapor deposited amorphous layers of N,N′‐bis(1‐naphthalenyl)‐N,N′‐diphenyl‐4,4′‐phenyldiamine (NPPDA) over a wide range of fields and temperature. The results are described within the framework of a formalism based on energetic disorder of the hopping sites. The variance of hopping site energies is 0.098 eV. The energy variance can be described by a model based on dipolar disorder. The model is based on the assumption that the total variance is comprised of a dipolar component and a van der Waals component. For NPPDA, the dipolar component is 0.080 eV and the van der Waals component is 0.067 eV.