Iridium complex and organic electroluminescence device using the same

An iridium complex of formula (1):

• wherein X is an oxygen atom, a sulfur atom, a selenium atom, NR3, or CR4R5, Y1 to Y3 are each independently a nitrogen atom or CR6, and L represents formula (2):
• wherein R1 to R9 are the same or different and each independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbocyclic ring having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 30 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms.