An organic EL device includes a first emitting layer and a second emitting layer, in which the first emitting layer contains a first host material, the second emitting layer contains a second host material, the first and the second host material are mutually different, the first emitting layer and the second emitting layer at least contains a compound that emits fluorescence having a main peak wavelength of 500 nm or less, respectively, the compound contained in the first emitting layer and that emits fluorescence having a main peak wavelength of 500 nm or less is the same as or different from the compound contained in the second emitting layer, and a triplet energy T.sub.1(H1) of the first host material and a triplet energy T.sub.1(H2) of the second host material satisfy a numerical formula (Numerical Formula 1),

T.sub.1(H1)>T.sub.1(H2)  (Numerical Formula 1).

An organic EL device includes a first emitting layer and a second emitting layer, in which the first emitting layer contains a first host material, the second emitting layer contains a second host material, the first and the second host material are mutually different, the first emitting layer and the second emitting layer at least contains a compound that emits fluorescence having a main peak wavelength of 500 nm or less, respectively, the compound contained in the first emitting layer and that emits fluorescence having a main peak wavelength of 500 nm or less is the same as or different from the compound contained in the second emitting layer, and a triplet energy T.sub.1(H1) of the first host material and a triplet energy T.sub.1(H2) of the second host material satisfy a numerical formula (Numerical Formula 1),

T.sub.1(H1)>T.sub.1(H2)  (Numerical Formula 1).

An organic electroluminescence device includes an anode, a cathode, a first emitting layer, and a second emitting layer provided between the first emitting layer and the cathode, in which the first emitting layer includes, as a first host material, a first compound that includes at least one group represented by a formula (11) below, the first compound being represented by a formula (1) below, the second emitting layer includes a second compound represented by a formula (2A) below as a second host material, and the first emitting layer is in direct contact with the second emitting layer.

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An organic electroluminescence device includes an anode, a cathode, a first emitting layer, and a second emitting layer provided between the first emitting layer and the cathode, in which the first emitting layer includes, as a first host material, a first compound that includes at least one group represented by a formula (11) below, the first compound being represented by a formula (1) below, the second emitting layer includes a second compound represented by a formula (2A) below as a second host material, and the first emitting layer is in direct contact with the second emitting layer.

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Provided is a novel metal complex that can be used as an electron transporting material. A metal complex represented by the following Formula (1) to the following Formula (3). R.sup.A1 to R.sup.A9, R.sup.C1 to R.sup.C8, and R.sup.E1 to R.sup.E6 are each independently a single bond, an alkylene group, an arylene group, a heteroarylene group, or a group represented by —R.sup.P1—P(═O)R.sup.P2—R.sup.P3—, R.sup.B1 to R.sup.B9, R.sup.D1 to R.sup.D8, and R.sup.F1 to R.sup.F6 are each independently a hydrogen atom, an. alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxv group, an amino group, a cyano group, a halogen atom, or a hydroxy group, one or more selected from the group consisting of R.sup.B1 to R.sup.B9 are a phenanthrolinyl group, one or more selected from the group consisting of R.sup.D1 to R.sup.D8 are a phenanthrolinyl group, and one or more selected from the group consisting of R.sup.F1 to R.sup.F6 are a phenanthrolinyl group, M is an alkali metal or an alkaline earth metal, Z is 1 or 2, and X is O or S.

Provided is a novel metal complex that can be used as an electron transporting material. A metal complex represented by the following Formula (1) to the following Formula (3). R.sup.A1 to R.sup.A9, R.sup.C1 to R.sup.C8, and R.sup.E1 to R.sup.E6 are each independently a single bond, an alkylene group, an arylene group, a heteroarylene group, or a group represented by —R.sup.P1—P(═O)R.sup.P2—R.sup.P3—, R.sup.B1 to R.sup.B9, R.sup.D1 to R.sup.D8, and R.sup.F1 to R.sup.F6 are each independently a hydrogen atom, an. alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxv group, an amino group, a cyano group, a halogen atom, or a hydroxy group, one or more selected from the group consisting of R.sup.B1 to R.sup.B9 are a phenanthrolinyl group, one or more selected from the group consisting of R.sup.D1 to R.sup.D8 are a phenanthrolinyl group, and one or more selected from the group consisting of R.sup.F1 to R.sup.F6 are a phenanthrolinyl group, M is an alkali metal or an alkaline earth metal, Z is 1 or 2, and X is O or S.

A light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode and including an emission layer, wherein the interlayer includes a heterocyclic compound of Formula 1:

A.sub.1B.sub.1].sub.n1  Formula 1

wherein, in Formula 1, the variables are defined herein.

A light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode and including an emission layer, wherein the interlayer includes a heterocyclic compound of Formula 1:

A.sub.1B.sub.1].sub.n1  Formula 1

wherein, in Formula 1, the variables are defined herein.

The present invention relates to a method for preparing a modification polymerization initiator with a high conversion ratio by minimizing side reactions. According to the method for preparing a modification polymerization initiator, a modification polymerization initiator which may easily initiate polymerization and provide a polymer with a functional group having affinity with a filler, may be prepared. Particularly, by performing the method using a continuous reactor, the production of by-products may be decreased, and as a result, the conversion ratio may be increased and a modification polymerization initiator with high purity may be prepared in a high yield.

The present invention relates to a method for preparing a modification polymerization initiator with a high conversion ratio by minimizing side reactions. According to the method for preparing a modification polymerization initiator, a modification polymerization initiator which may easily initiate polymerization and provide a polymer with a functional group having affinity with a filler, may be prepared. Particularly, by performing the method using a continuous reactor, the production of by-products may be decreased, and as a result, the conversion ratio may be increased and a modification polymerization initiator with high purity may be prepared in a high yield.