Composition and light emitting device using the same

A composition comprising a phosphorescent compound of formula (1) and a phosphorescent compound of formula (2),

• wherein the maximum peak wavelength of the emission spectrum of the phosphorescent compound of formula (1) is 380 nm or more and less than 495 nm, and
• the maximum peak wavelength of the emission spectrum of the phosphorescent compound of formula (2) is 495 nm or more and less than 750 nm:
• wherein
• M1 represents a ruthenium atom, a rhodium atom, a palladium atom, an iridium atom or a platinum atom,
• n1 represents an integer of 1 or more, n2 represents an integer of 0 or more, provided that n1+n2 is 2 or 3, and n1+n2 is 3 when M1 is a ruthenium atom, a rhodium atom or an iridium atom, and n1+n2 is 2 when M1 is a palladium atom or a platinum atom,
• E1 and E2 each independently is a carbon atom or a nitrogen atom, and at least one of E1 and E2 is a carbon atom,
• the ring R1 is an optionally substituted 5-membered aromatic heterocyclic ring, and when a plurality of substituents are present, they can be the same or different and can be combined together to form a ring together with the atoms to which they are attached, and when a plurality of the rings R1 are present, they can be the same or different,
• the ring R2 is an optionally substituted aromatic hydrocarbon ring or an optionally substituted aromatic heterocyclic ring, and when a plurality of substituents are present, they can be the same or different and can be combined together to form a ring together with the atoms to which they are attached, and when a plurality of the rings R2 are present, they can be the same or different,
• the ligand constituted of the ring R1 and the ring R2 is a ligand constituted of atoms selected from the group consisting of a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom, and at least one ring selected from the group consisting of the ring R1 and the ring R2 has a group represented by the formula (1-S), and
• A1-G1-A2 is an anionic bidentate ligand, A1 and A2 each independently is a carbon atom, an oxygen atom or a nitrogen atom and these atoms can be an atom constituting a ring, G1 represents a single bond or an atomic group constituting the bidentate ligand together with A1 and A2, and when a plurality of A1-G1-A2 are present, they can be the same or different:
• wherein
• Ar1S is an aryl group optionally substituted with an alkyl group, a cycloalkyl group, an alkoxy group or a cycloalkoxy group, wherein the alkyl group, the cycloalkyl group, the alkoxy group and the cycloalkoxy group each is optionally further substituted with a substituent,
• n1S is an integer of 0 to 10, and
• Ar2S is an arylene group optionally substituted with an alkyl group, a cycloalkyl group, an alkoxy group or a cycloalkoxy group, wherein the alkyl group, the cycloalkyl group, the alkoxy group and the cycloalkoxy group each is optionally further substituted with a substituent, and when a plurality of Ar2S are present, they can be the same or different:
• wherein
• M2 is a ruthenium atom, a rhodium atom, a palladium atom, an iridium atom or a platinum atom,
• n3 is an integer of 1 or more, n4 represents an integer of 0 or more, provided that n3+n4 is 2 or 3, and n3+n4 is 3 when M2 is a ruthenium atom, a rhodium atom or an iridium atom, and n3+n4 is 2 when M2 is a palladium atom or a platinum atom,
• E4 is a carbon atom or a nitrogen atom,
• the ring L1 is an optionally substituted 6-membered aromatic heterocyclic ring, and when a plurality of substituents are present, they can be the same or different and can be combined together to form a ring together with the atoms to which they are attached, and when a plurality of the rings L1 are present, they can be the same or different,
• the ring L2 is an optionally substituted aromatic hydrocarbon ring or an optionally substituted aromatic heterocyclic ring, and when a plurality of substituents are present, they can be the same or different and can be combined together to form a ring together with the atoms to which they are attached, and when a plurality of the rings L2 are present, they can be the same or different,
• the substituents which the ring L1 optionally has and the substituents which the ring L2 optionally has can be combined together to form a ring together with the atoms to which they are attached,
• the ligand constituted of the ring L1 and the ring L2 is a ligand constituted of atoms selected from the group consisting of a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom, and at least one ring selected from the group consisting of the ring L1 and the ring L2 is substituted with a group of formula (1-T), and
• A3-G2-A4 is an anionic bidentate ligand, A3 and A4 each independently is a carbon atom, an oxygen atom or a nitrogen atom and these atoms can be an atom constituting a ring, G2 is a single bond or an atomic group constituting the bidentate ligand together with A3 and A4, and when a plurality of A3-G2-A4 are present, they can be the same or different:
• wherein
• Ar1T is an aryl group optionally substituted with an alkyl group, a cycloalkyl group, an alkoxy group or a cycloalkoxy group, wherein the alkyl group, the cycloalkyl group, the alkoxy group and the cycloalkoxy group each is optionally further substituted with a substituent,
• n1T is an integer of 0 to 10, and
• Ar2T is an arylene group optionally substituted with an alkyl group, a cycloalkyl group, an alkoxy group or a cycloalkoxy group, wherein the alkyl group, the cycloalkyl group, the alkoxy group and the cycloalkoxy group each is optionally further substituted with a substituent, and when a plurality of Ar2T are present, they can be the same or different.