Patent ID: 7388327
Filing Date: 2008-06-17
Classification: C09K,H01L,H05B,Y10S

Abstract:
1. A light-emitting device comprising: a pair of electrodes; and a light-emitting layer provided between the pair of electrodes, wherein the light-emitting layer has a host and two different dopants, and wherein each of the two different dopants is a phosphorescent metal complex having an organic ligand, and among the two different dopants, a first dopant having a longer maximum-emission wavelength (i) is contained in the light-emitting layer at a lower concentration than a concentration of a second dopant; (ii) includes a 1-phenylisoquinoline ligand represented by the following general formula (1): wherein R1, R2, and R3 are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a nitro group, a disubstituted amino group (the substituents are each independently a phenyl group or naphthyl group that may have a sub stituent (the substituent is a halogen atom, a methyl group, or a trifluoromethyl group), or a linear or branched alkyl group having 1 to 8 carbon atoms where a hydrogen atom in the alkyl group may be substituted by a fluorine atom), a trialkylsilyl group (the alkyl groups are each independently linear or branched alkyl groups having 1 to 8 carbon atoms), and a linear or branched alkyl group having 1 to 20 carbon atoms (one methylene group or two or more unadjacent methylene groups in the alkyl group may be replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —CH═CH—, or —C≡C—, and at least one methylene group in the alkyl group may be replaced by a bivalent aromatic ring group that may have a substituent (the substituent is a halogen atom, a cyano group, a nitro group, a trialkylsilyl group (the alkyl groups are each independently linear or branched alkyl groups having 1 to 8 carbon atoms), or a linear or branched alkyl group having 1 to 20 carbon atoms (one methylene group or two or more unadjacent methylene groups in the alkyl group may be replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —CH═CH—, or —C≡C—, and a hydrogen atom in the alkyl group may be substituted by a fluorine atom))), and at least one of R1, R2, and R3 is not a hydrogen atom; and (iii) all ligands thereof are bonded to the metal of the metal complex at N and C atoms; and the second dopant is present in amounts of at least 7% by weight based on the total weight of the light emitting layer.