Patent ID: 8183560

Claim:
A light emitting device comprising at least an emissive layer existing between an anode and a cathode, which emits light by means of electric energy, wherein the emissive layer contains at least a compound having a pyrromethene skeletal structure represented by the formula (1) or a metal complex thereof, and a naphthacene derivative represented by the formula (2): wherein R 1 to R 7 may be the same or different and are selected from among hydrogen, an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkoxy group, an alkylthio group, an arylether group, an arylthioether group, an aryl group, a heteroaryl group, halogen, a cyano group, a carbonyl group, a carboxyl group, an oxycarbonyl group, a carbamoyl group, an amino group, a silyl group, a phosphine oxide group, and a ring structure formed between adjacent substituents; X represents a carbon atom or a nitrogen atom, and R 7 is absent when X is a nitrogen atom; and metal of a metal complex is at least one selected from among boron, beryllium, magnesium, chromium, iron, cobalt, nickel, copper, zinc and platinum: wherein R 8 to R 19 may be the same or different and are selected from among hydrogen, an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkoxy group, an alkylthio group, an arylether group, an arylthioether group, an aryl group, a heteroaryl group, halogen, a cyano group, a carbonyl group, a carboxyl group, an oxycarbonyl group, a carbamoyl group, an amino group, a silyl group, a phosphine oxide group, and a ring structure formed between adjacent substituents, and at least one of R 8 to R 19 in the naphthacene derivative represented by formula (2) is an aryl group.