Provided are a compound for an organic optoelectronic device represented by a combination of Chemical Formula 1 and Chemical Formula 2, a composition for an organic optoelectronic device including the same, an organic optoelectronic device, and a display device. Details for Chemical Formula 1 and Chemical Formula 2 are as defined in the specification.

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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A light emitting element that includes a first compound represented by a specific chemical formula in which an ortho-type or kind penta-phenyl group is bonded to a fused polycyclic compound including at least one boron atom and a heteroatom is provided. The light emitting element has a long-lifetime.

A light emitting element includes a first electrode, a second electrode, and an emission layer between the first electrode and the second electrode and includes a compound represented by Formula 1 below, thereby exhibiting a long service life characteristic.

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A display device includes a sacrificial layer positioned between an encapsulation layer and a light-emitting element that includes a first compound that is the same as a first compound of a light-emitting layer of the light-emitting element, thereby protecting the light-emitting element from an outgas of the encapsulation layer to prevent the generation of dark spots.

A light-emitting device having an electron transport layer that includes a first electron transport layer including an inorganic oxide and a second electron transport layer including an organic material is provided. The first electrode is a reflective electrode.

The present disclosure relates to a plurality of host materials comprising at least one first host compound represented by the following formula 1 and at least one second host compound represented by the following formula 2, and an organic electroluminescent device comprising the same. By comprising the specific combination of the compound according to the present disclosure as host materials, an organic electroluminescent device having high luminous efficiency and/or long lifespan characteristics can be provided.

A light emitting element that includes a first electrode, a second electrode on the first electrode, an emission layer between the first electrode and the second electrode, and a hole transport region which is between the first electrode and the emission layer is provided. The emission layer includes an amine compound represented by Formula 1:

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A compound and an organic optoelectronic device, the compound being represented by Chemical Formula 1-3a-I or Chemical Formula 1-4a-I: ##STR00001##

A method comprising providing a carbonaceous material, the substrate having a first thermal conductivity. The method further comprises depositing a first masking layer having a second thermal conductivity on at least a portion of the substrate, a ratio of the second thermal conductivity to the first thermal conductivity being less than or equal to 1:30. The method further comprises depositing a second masking layer on the first masking layer to form an etch mask, and etching an exposed portion of the substrate.