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 contains a first compound represented by a formula (101) below as a first host material, the second emitting layer contains a second compound represented by a formula (2) 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 contains a first compound represented by a formula (101) below as a first host material, the second emitting layer contains a second compound represented by a formula (2) below as a second host material, and the first emitting layer is in direct contact with the second emitting layer.

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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.

Specific polycyclic compounds, a material for an organic electroluminescence device comprising said specific polycyclic compound, an organic electroluminescence device comprising said specific polycyclic compound, an electronic equipment comprising said organic electroluminescence device, a process for preparing said polycyclic compounds, and the use of said polycyclic compounds in an organic electroluminescence. (Formula I) (I)

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Specific polycyclic compounds, a material for an organic electroluminescence device comprising said specific polycyclic compound, an organic electroluminescence device comprising said specific polycyclic compound, an electronic equipment comprising said organic electroluminescence device, a process for preparing said polycyclic compounds, and the use of said polycyclic compounds in an organic electroluminescence. (Formula I) (I)

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An organic light emitting diode (OLED) includes at least one emitting material layer (EML) disposed between two electrodes and including a first compound of a pyrimidine-based organic compound substituted with at least one electron-withdrawing group and a second compound of an organic compound having a tetracene-based core. The OLED can be included in an organic light emitting device. The first compound and the second compound can be the same emitting material layer or adjacently disposed emitting material layers. The OLED can lower its driving voltage and improve its luminous efficiency utilizing the advantages of the first and second compounds by adjusting energy levels between the first and second compounds.

An organic light emitting diode (OLED) includes at least one emitting material layer (EML) disposed between two electrodes and including a first compound of a pyrimidine-based organic compound substituted with at least one electron-withdrawing group and a second compound of an organic compound having a tetracene-based core. The OLED can be included in an organic light emitting device. The first compound and the second compound can be the same emitting material layer or adjacently disposed emitting material layers. The OLED can lower its driving voltage and improve its luminous efficiency utilizing the advantages of the first and second compounds by adjusting energy levels between the first and second compounds.

A light emitting element includes a first electrode, a second electrode disposed on the first electrode, and an emission part disposed between the first electrode and the second electrode and including a first emission layer and a second emission layer disposed on the first emission layer, the first emission layer may include a first host, and a first dopant, and the second emission layer may include a hole transport host different from the first host, an electron transport host, and a second dopant. A first hole mobility of the first host may be in a range of about 5.0×10.sup.−6 cm.sup.2/Vs to about 1.0×10.sup.−3 cm.sup.2/Vs, a second hole mobility of a host mixture including the hole transport host and the electron transport host may be in a range of about 1.0×10.sup.−6 cm.sup.2/Vs to about 1.0×10.sup.−4 cm.sup.2/Vs, and the first hole mobility may be larger than the second hole mobility.

A light emitting element includes a first electrode, a second electrode disposed on the first electrode, and an emission part disposed between the first electrode and the second electrode and including a first emission layer and a second emission layer disposed on the first emission layer, the first emission layer may include a first host, and a first dopant, and the second emission layer may include a hole transport host different from the first host, an electron transport host, and a second dopant. A first hole mobility of the first host may be in a range of about 5.0×10.sup.−6 cm.sup.2/Vs to about 1.0×10.sup.−3 cm.sup.2/Vs, a second hole mobility of a host mixture including the hole transport host and the electron transport host may be in a range of about 1.0×10.sup.−6 cm.sup.2/Vs to about 1.0×10.sup.−4 cm.sup.2/Vs, and the first hole mobility may be larger than the second hole mobility.