Since organic electroluminescent elements (which may hereinafter also be referred to as “elements” or “organic EL elements”) are capable of high-luminance light emitting with driving at a low voltage, they have been actively researched and developed. The organic electroluminescent elements have organic layers between a pair of electrodes, and utilize, for light emitting, energy of the exciton generated as a result of recombination of electrons injected from a cathode and holes injected from an anode in the organic layer.
Recently, by using a phosphorescent light emitting material such as an iridium complex and a platinum complex, an increase in the efficiency of elements have been developed. Further, doped elements using a light emitting layer doped in a host material, using a light emitting material as a guest material, have been widely adopted and used. Such an iridium complex, an iridium complex having a structure having divalent ligands, containing two 5- or 6-membered rings connected via a single bond, coordinated at a total of 3 sites on iridium atoms, in which carbon atoms or nitrogen atoms constituting each of the 5- or 6-membered rings are coordinated on iridium atoms, have been widely known. For example, PTL 1 describes that by using an iridium complex exhibiting green phosphorescent light emission, in which one or two of each of a ligand having a benzene ring substituted with a phenyl group and a pyridine ring connected via a single bond, and a ligand having a benzene ring and a pyridine ring connected via a single bond, an organic electroluminescent element having excellent luminous efficiency and durability is obtained. Further, PTL 2 describes that by using an iridium complex exhibiting phosphorescent light emission, in which one or two of each of a ligand having a benzene ring substituted with a phenyl group, a hetero ring group of a 5- or 6-membered ring, a bicyclic fused ring group or the like, and a pyridine ring connected via a single bond, and a ligand having a benzene ring and a pyridine ring connected via a single bond are used, an organic electroluminescent element having excellent color, luminous efficiency, and durability is obtained.
On the other hand, an iridium complex having a ligand, in which one of two 5- or 6-membered rings in the ligand is fused with another ring via a single bond, has been known. For example, PTL 3 describes that by using an iridium complex exhibiting phosphorescent light emission, in which one ligand having a fused ring containing three rings and a pyridine ring connected via a single bond, and two ligands having a benzene ring and a pyridine ring connected via a single bond are used, an organic electroluminescent element having excellent luminous efficiency and durability is obtained.
In addition, PTL 4 describes an iridium complex having ligands with various structures, and also describes that by using the iridium complex described in the same literature in an organic layer formed by a wet type film-forming method, an organic electroluminescent element having high durability and high efficiency can be provided.