Syntheses and characterization of soluble phthalocyanine derivatives for organic electroluminescent devices

Metal–4,4′,4″,4‴-tetraamino phthalocyanines (MT4APc) for organic electroluminescent devices were prepared and characterized, where M is Co, Cu and Zn. The phthalocyanines were soluble in common organic solvents, and thus easily coated with 2,2′-bis(3,4-dicarboxy-phenyl) hexafluoroisopropanedianhydride–2,4,6-trimethyl-1,3-phenylene-diamine (6FDA–3MPDA) polyimide, a polymer matrix, onto an ITO glass by the spin-coating method. The structures of the devices used in this work were ITO/Alq3/Al and ITO/TPD and MT4APc-dispersed 6FDA–3MPDA PI/Alq3/Al. The phthalocyanines-dispersed polyimide double-layer devices showed lower turn-on voltages and higher relative efficiencies than the single-layer device without phthalocyanines. The relative efficiency of MT4APc and TPD as a hole-transporting layer was found to be in the order CuT4APc>CoT4APc≈TPD>ZnT4APc.