Organic electrophotographic receptors have been enabled by the develop
ment of unique classes of high dielectric strength glassy polymer coat
ings which, through insulating are nevertheless capable of transportin
g injected charge with relatively high mobility and negligible loss to
deep traps. Key features of electronic transport in these materials a
nd the underlying physics are described. Additionally, it is demonstra
ted that these trap free transport polymers provide a unique venue for
the exploration of contact behavior and the factors controlling injec
tion efficiency in disordered organic solids.