Electroluminescent device with polyphenyl hydrocarbon hole transport layer

An organic multilayer electroluminescent device including an anode and cathode, and comprising therebetween:

• a hole transport layer;
• and
• an electron transport layer disposed in operative relationship with the hole transport layer;
• wherein:
• the hole transport layer includes an organic compound having the formula:
• wherein
• R is an alkyl group of from 1 to 12 carbon atoms;
• and
• Ar is a substituted or unsubstituted phenyl or naphthyl moiety;
• the substituents on the phenyl or naphthyl moiety are individually hydrogen, or alkyl of from 1 to 24 carbon atoms, aryl or substituted aryl of from 5 to 28 carbon atoms, heterouryl or substituted heteroaryl of from 5 to 28 carbon atoms, fluorine, chlorine or bromine atoms, or a cyano group.