| 摘要 |
PROBLEM TO BE SOLVED: To provide an organic electroluminescent element which has high luminous efficiency, a long light-emission life, a low driving voltage, and small change in the driving voltage due to aging, even when used at high temperature.SOLUTION: An organic electroluminescent element comprises: a positive electrode; a negative electrode; and an organic layer which is sandwiched between the positive and negative electrodes, and includes at least a luminous layer. At least one layer included in the organic layer includes a neutral phosphorescence-emitting organometallic complex which includes a transition metal complex as a central metal. A ligand of the neutral phosphorescence-emitting organometallic complex has a structure where a ring A, including an atom covalently bonded to the central metal as a constituent atom, and a ring B, including an atom coordinately bonded to the central metal as a constituent atom, are directly bond. The atom included in the ring A, being covalently bonded to the central metal, and the atom included in the ring B, being coordinately bonded to the central metal, are the same, and the ring A and the ring B are bonded together with a specific linking group. A ring structure which is newly formed with the linking group and parts of the ring A and the ring B is non-aromatic. |
