A light emitting device including a first electrode and a second electrode facing each other, and a first blue stack, a first charge generation layer, and a phosphorescent stack disposed between the first electrode and the second electrode. The phosphorescent stack includes a hole transport layer, a red light emitting layer, a green light emitting layer, and an electron transport layer. The red light emitting layer includes an electron transport host represented by Formula 1, a hole transport host different from the hole transport layer, and a red dopant.

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Discussed is a light-emitting device that can include a first electrode and a second electrode facing each other, and disposed on a substrate; a first light emitting stack and a second light emitting stack between the first electrode and the second electrode; and a charge generation stack between the first light emitting stack and the second light emitting stack. The charge generation stack can include a first layer including a first host, a second host, and a metal dopant, and a second layer including the first host, the metal dopant, a third host, and a p-type organic dopant. Amounts of the metal dopant in the first layer and the second layer respectively can increase in going towards an interface between the first layer and the second layer.

Discussed is a light-emitting device that can include a first electrode and a second electrode facing each other, and disposed on a substrate; a first light emitting stack and a second light emitting stack between the first electrode and the second electrode; and a charge generation stack between the first light emitting stack and the second light emitting stack. The charge generation stack can include a first layer including a first host, a second host, and a metal dopant, and a second layer including the first host, the metal dopant, a third host, and a p-type organic dopant. Amounts of the metal dopant in the first layer and the second layer respectively can increase in going towards an interface between the first layer and the second layer.

Disclosed are a light emitting element and a display device including the same, wherein a hole generation layer is further provided between a hole transport layer and an emission layer, in addition to an electron blocking layer, in order to control the speed of electrons and holes introduced into the emission layer, whereby it is possible to prevent accumulation of carriers at the electron blocking layer or the hole transport layer, and therefore it is possible to reduce turn-on voltage, to maintain uniform efficiency irrespective of change in current density, to prevent defects at specific gradation, and to increase lifetime.

Disclosed are a light emitting element and a display device including the same, wherein a hole generation layer is further provided between a hole transport layer and an emission layer, in addition to an electron blocking layer, in order to control the speed of electrons and holes introduced into the emission layer, whereby it is possible to prevent accumulation of carriers at the electron blocking layer or the hole transport layer, and therefore it is possible to reduce turn-on voltage, to maintain uniform efficiency irrespective of change in current density, to prevent defects at specific gradation, and to increase lifetime.

Embodiments provide an organometallic compound, a light-emitting device including the organometallic compound, and an electronic apparatus including the light-emitting device. The light-emitting device includes a first electrode, a second electrode facing the first electrode, an interlayer between the first electrode and the second electrode and including an emission layer, and the organometallic compound, which is represented by Formula 1.

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The description of Formula 1 is provided in the specification.

Disclosed is a device that includes an emissive material or region including a host that is doped with a first material as an emitter that is an acceptor and a phosphorescent-capable second material as a sensitizer. The first material and the second material each has a first singlet state and a first triplet state. The first triplet state of the second material is not lower than the first triplet state of the first material. The second material transfers excitons to the first material and the excitons that transition to the first triplet state of the first material can be activated to the first singlet state of the first material through a thermal activation process.

An organic light emitting device includes: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode, the organic layer including an emission layer, wherein the organic layer includes a first compound, a second compound, a third compound, and a fourth compound, and the first compound to the fourth compound satisfy Equations 1 to 8:
E.sub.1,LUMO≥E.sub.2,LUMO+0.15 electron volts (eV)  Equation 1
E.sub.1,HOMO≥E.sub.2,HOMO+0.15 eV  Equation 2
E.sub.1,T1≥E.sub.4,T1  Equation 3
E.sub.2,T1≥E.sub.4,T1  Equation 4
E.sub.3,T1≥E.sub.4,T1  Equation 5
E.sub.3,LUMO≥E.sub.2,LUMO+0.1 eV  Equation 6
−5.6 eV≥E.sub.3,HOMO  Equation 7
E.sub.gap1≥E.sub.gap3.  Equation 8

Novel Iridium complexes having three different bidentate ligands useful for phosphorescent emitters in OLEDs are disclosed. At least one of the three different bidentate ligands is a carbene ligand.

An organometallic compound is represented by Formula 1. An organic light-emitting device includes a first electrode, a second electrode, and an organic layer including an emission layer between the first electrode and the second electrode, wherein the organic layer includes at least one of the organometallic compound represented by Formula 1. An apparatus includes the organic light-emitting device.