A display device includes a display circuit layer including a first surface and a second surface and including a display area in which an image is displayed on the first surface, a heat conductive sheet overlapping the display circuit layer below the second surface, and an optical fingerprint sensor inside the display area below the heat conductive sheet and overlapping the display circuit layer. The heat conductive sheet includes a first area overlapping the optical fingerprint sensor and a second area overlapping the display area around the optical fingerprint sensor. The heat conductive sheet includes a heat conductive material, has a shape having a light transmittance required for sensing by the optical fingerprint sensor in the first area, and has no light transmittance in the second area.

A compound of:

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is disclosed. In Formula III, ring B and ring C are each independently a 5 or 6-membered carbocyclic or heterocyclic ring; A-B represents a bonded pair of carbocyclic or heterocyclic rings coordinated to a metal M via a nitrogen atom in ring A and an sp.sup.2 hybridized atom in ring B; A-C represents a bonded pair of carbocyclic or heterocyclic rings; M is a metal having an atomic number greater than 40; L′ is a monoanionic bidentate ligand; m is the oxidation state of the metal M; and n is at least 1.

A compound of:

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is disclosed. In Formula III, ring B and ring C are each independently a 5 or 6-membered carbocyclic or heterocyclic ring; A-B represents a bonded pair of carbocyclic or heterocyclic rings coordinated to a metal M via a nitrogen atom in ring A and an sp.sup.2 hybridized atom in ring B; A-C represents a bonded pair of carbocyclic or heterocyclic rings; M is a metal having an atomic number greater than 40; L′ is a monoanionic bidentate ligand; m is the oxidation state of the metal M; and n is at least 1.

A display device includes: a substrate; a flattened layer; at least one first light-emitting element; at least one second light-emitting element; at least one first drive circuit; and at least one second drive circuit, wherein light emitted by the first light-emitting element is taken out through the substrate, light emitted by the second light-emitting element is taken out from a direction opposite to a direction in which the light emitted by the first light-emitting element is taken out, the first light-emitting element is provided in an opening provided in the flattened laver, the second light-emitting element is provided in a layer above the flattened layer and overlaps the flattened layer, and the first drive circuit and the second drive circuit are provided closer to the substrate than the second light-emitting element.

A method for manufacturing a quantum dot layer includes: performing first application of applying, to a position overlapping with a substrate, a first solution including a plurality of particles including a core and a first ligand, a first inorganic precursor, and a first solvent; performing first heating of heating first solution to a first temperature or higher after the performing first application, the first temperature being a higher temperature of a melting point of the first ligand and a boiling point of the first solvent; and performing second heating of heating the first inorganic precursor to a second temperature after the performing first heating, the second temperature being higher than the first temperature and being a temperature, at which the first inorganic precursor epitaxially grows around the core and at which a first shell configured to coat the core is formed to form a plurality of first quantum dots.

A light-emitting device includes a first sub-pixel provided with a first light emitter, and a second sub-pixel provided with a second light emitter and constituting, together with the first sub-pixel, one of a plurality of pixels. The first light emitter has a first cathode, a first anode, and a first light-emitting layer containing a first quantum dot and disposed between the first cathode and the first anode. The second light emitter has a second cathode, a second anode, and a second light-emitting layer containing a second quantum dot and disposed between the second cathode and the second anode. The second quantum dot emits light having a longer light-emission wavelength than the first quantum dot. The first light-emitting layer is thicker than the second light-emitting layer.

Alight-emitting element includes an anode electrode, a cathode electrode, a light-emitting layer, a positive hole transport layer, and an electron transport layer. The light-emitting layer, the positive hole transport layer, and the electron transport layer are provided between the anode electrode and the cathode electrode. The light-emitting layer includes QD phosphor particles, a positive hole transport substance configured to transport positive holes transported thereto by the positive hole transport layer, an electron transport substance configured to transport electrons transported thereto by the electron transport layer, and a photosensitive host material.

A quantum dot including a core comprising a first semiconductor nanocrystal including a zinc chalcogenide and a semiconductor nanocrystal shell disposed on the surface of the core and comprising zinc, selenium, and sulfur. The quantum dot does not comprise cadmium, emits blue light, and may exhibit a digital diffraction pattern obtained by a Fast Fourier Transform of a transmission electron microscopic image including a (100) facet of a zinc blende structure. In an X-ray diffraction spectrum of the quantum dot, a ratio of a defect peak area with respect to a peak area of a zinc blende crystal structure is less than about 0.8:1. A method of producing the quantum dot, and an electroluminescent device including the quantum dot are also disclosed.

A light-emitting element includes, in sequence, an anode, a hole transport layer, a luminous layer containing a plurality of quantum dots, an electron transport layer, and a cathode. The electron transport layer includes a plurality of inorganic nanoparticles having electron transportability, and an organic layer having electron transportability. The organic layer partly contains the plurality of inorganic nanoparticles, and includes a plurality of first hollows in an interface adjacent to the luminous layer. The plurality of first hollows are filled with the plurality of quantum dots.

A light-emitting element includes, in order of listing, an anode, an hole transport layer, an emission layer, and a cathode. The light-emitting element includes an reducing material disposed in at least a part between the anode and the hole transport layer, being in contact with the anode and the hole transport layer, and containing a reducing material that reduces a layer having the hole transport layer. The reducing material contains, in a structure of the reducing material, hydrogen either at a concentration ratio of 1 to 1 with resect to a base metal, or at a larger concentration ratio than the base metal.