Aryl amines selected for the hole transporting layer, which layer generally is of a thickness of from about 5 microns to about 50 microns, and preferably of a thickness of from about 10 microns to about 40 microns, include those of the following formula: ##STR3## dispersed in a highly insulating and transparent organic resinous binder wherein X is an alkyl group or a halogen, especially those subs