Disclosed herein are light emitting device that emit highly circularly polarized light. These devices may be used to form a dot-matrix display or an electronic information display comprised of a series of photopolymerizable, chiral liquid crystalline layers that can be solvent cast on a substrate. The mixture of chiral materials in each successive layer may be blended in such a way that each layer has the same chiral pitch and may also be blended so that the ordinary and extraordinary refractive indices in each layer match the other layers such that the complete assembly of layers will optically function as a single relatively thick layer of chiral liquid crystal. The chiral nematic material in each layer can spontaneously adopt a helical structure with a helical pitch. Further disclosed are pixel structures that not only emit light with brightness and chromaticity information, but also depth of focus information as well.

An electron transport layer includes a first electron transport film and a second electron transport film. The second electron transport film is disposed at a side of the first electron transport film and is stacked with the first electron transport film. An energy level of a conduction band of a material included in the second electron transport film is greater than an energy level of a conduction band of a material included in the first electron transport film, and the energy level of the conduction band of the material included in the second electron transport film is less than an energy level of a conduction band of a material included in the light-emitting layer.

An inorganic light emitting diode in which at least one energy control layer including an organometallic compound interacting with a hydroxyquinoline moiety is disposed between an emitting material layer and at least one charge transfer layer and an inorganic light emitting device including the diode are disclosed. An exciton recombination zone is formed at the central region in the EML, and inorganic luminescent particles have minimal surface defects by introducing the energy control layer. The inorganic light emitting diode and the inorganic light emitting device can improve their color purity and luminous efficiency.

A novel light-emitting device that is highly convenient, useful, or reliable is provided. The light-emitting device includes a first electrode, a second electrode, a unit, and a first layer. The second electrode includes a region overlapping with the first electrode. The unit includes a region positioned between the first electrode and the second electrode. The unit includes a second layer and a third layer. The second layer includes a region where the third layer is positioned between the second layer and the first electrode. The second layer contains a light-emitting material. The first layer includes a region positioned between the third layer and the first electrode. The first layer contains a material having an acceptor property and a first material. The first layer includes a first region and a second region. The first region includes a region positioned between the second region and the first electrode. The first region contains the material having an acceptor property at a first concentration. The second region contains the material having an acceptor property at a second concentration. Note that the second concentration is higher than zero and lower than the first concentration.

A light-emitting device with high resistance to heat in a fabrication process is provided. The light-emitting device includes an EL layer between an anode and a cathode, and the EL layer includes at least a light-emitting layer. The light-emitting device includes, between the light-emitting layer and the cathode, a first layer in contact with the light-emitting layer. The light-emitting layer includes a light-emitting substance, a first organic compound, and a second organic compound. The first layer includes a third organic compound different from the first organic compound and the second organic compound. The light-emitting substance emits green to yellow light. The third organic compound includes a bicarbazole skeleton and a heteroaromatic ring skeleton including one selected from a pyridine ring, a diazine ring, and a triazine ring.

An organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; an emission layer between the first electrode and the second electrode; a hole transport region between the first electrode and the emission layer; and an electron transport region between the emission layer and the second electrode, wherein the electron transport region includes a first compound, at least one selected from the hole transport region and the electron transport region includes a second compound, the first compound is represented by one selected from Formulae 1A to 1D, and the second compound is represented by Formula 2A or Formula 2B: ##STR00001##

An electroluminescent device and a display device including the electroluminescent device. The electroluminescent device includes a first electrode and a second electrode each having a surface opposite the other; a light emitting layer disposed between the first electrode and the second electrode, the light emitting layer including quantum dots; and an electron transport layer disposed between the light emitting layer and the second electrode, the electron transport layer including inorganic material nanoparticles including an anion dopant including P, N, C, Cl, F, Br, S, or a combination thereof.

The present disclosure provides an organic electroluminescent device including: an anode; a cathode; and one or more organic material layers interposed between the anode and cathode and selected from the group consisting of a hole injection layer, a hole transporting layer, a light emitting layer, an electron transporting layer, and an electron injection layer, and further including a lifetime enhancement layer (LEL) between the light emitting layer and the electron transporting layer.

A light-emitting element is provided with a first electrode which is an anode; a second electrode which is a cathode; a light-emitting layer provided between the first electrode and the second electrode; an oxide layer provided between the first electrode or the second electrode and the light-emitting layer; and an oxide layer provided in contact with the oxide layer and between the oxide layer and the second electrode, wherein of the oxide layer and the oxide layer, the layer closer to the light-emitting layer is formed from a semiconductor; and an oxygen atom density in the oxide layer is less than an oxygen atom density in the oxide layer.

An organic electroluminescence device includes an anode, a cathode, a first emitting layer and a second emitting layer that are interposed between the anode and the cathode and are in a direct contact with each other, and a first electron transporting layer between the cathode and the first emitting layer and the second emitting layer being in a direct contact with each other. The first emitting layer contains a first compound represented by a formula (1) as a first host material, the first compound having at least one group represented by a formula (11). The second emitting layer contains a second compound represented by a formula (2) as a second host material. The first electron transporting layer contains a third compound represented by a formula (3). ##STR00001##