Light-Emitting Device and Luminous Body Using Rare Earth Complexes

PURPOSE : Provided are a light emitting device which has excellent solubility in a solvent, resin dispersibility, high luminous strength and long lifetime, and a light emitting medium. CONSTITUTION : The light emitting device is provided with a light emitting part; and a light emitting medium comprising a rare earth metal complex using a compound represented by the formula 1 as a ligand, wherein X and Y are identical or different each other and are O, S or Se; R1 to R4 are a linear or branched C1-C20 alkyl or alkoxy group, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group or their substituted groups, and all the R1 to R4 are not identical; n is an integer of 2-20; and Z and W are identical or different each other and are H, D (heavy hydrogen), a halogen atom or an alkyl group. Preferably the rare earth metal complex comprises the ligand represented by the formula 1 and a β-diketone ligand. © KIPO 2005