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, Ca and Zn. The phthalocyanines were soluble in common organic solvents, and thus easily coated with 2,2'-bis(3,4-dicarboxy-phenyl) hexafluoroisopropane dianhydride-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 MT4A-Pc and TPD as a hole-transporting layer was found to be in the order CuT4APc > CoT4APc approximate to TPD > ZnT4A-Pc. (C) 2001 Elsevier Science B.V. All rights reserved.