US Patent 7179544 Organic electroluminescent element

An organic electroluminescent element comprising: a pair of electrodes; and an organic layer provided between the pair of electrodes, the organic layer comprising a light-emitting layer and an electron transporting layer, wherein the light-emitting layer contains at least one phosphorescence-emitting material and at least one metal complex functioning as a host material, and the electron transporting layer contains a compound represented by the formula (E-I):LA)m  (E-I)wherein A represents a monovalent heterocyclic group wherein two or more aromatic hetero rings are condensed, the heterocyclic groups represented by A is the same or different from each other, m represents an integer of 2 or more, and L represents an m-valent linking group.