White-light-emitting organic electroluminescent devices using new chelate metal complexes

Abstract

In this study, several. lanthanide complexes such as Eu(TTA)(3)(Phen), Tb(ACAC)(3)(Cl-Phen) were synthesized and the white light electroluminescence (EL) characteristics of their thin films were investigated, where the devices having structures of anode/TPD[Tb(ACAC)(3)(Cl-Phen)/Eu(TTA)(3)(Phen)/Alq(3) or Bebq(2)/cathode and the low work function metal alloy such as Li:Al was used as the electron injecting electrode (cathode). Details on the white light-emitting characteristics of these device structures were explained by the energy band diagrams of various materials used in these structures, where the energy levels of new materials such as ionization potential (IP) and electron affinity (EA) were measured by cyclic voltametric method. (C) 2000 Published by Elsevier Science S.A.