A light-emitting element includes an anode electrode and a cathode electrode, and is provided with a first hole transport layer, a second hole transport layer, a light-emitting layer, a first electron transport layer, and a second electron transport layer. At a HOMO level, an energy level difference between the second hole transport layer and the light-emitting layer on the second hole transport layer side is from 0.0 eV to 0.15 eV, and at a LUMO level, an energy level difference between the first electron transport layer and the light-emitting layer on the first electron transport layer side is from 0.0 eV to 0.15 eV. The second electron transport layer is a mixed layer that includes an organic material having electron transport properties and an electron-accepting material and contains the electron-accepting material in an amount greater than 50 mass %.

An electroluminescent display device is disclosed. The electroluminescent display device includes a substrate having thereon a first sub pixel and a second sub pixel, a first electrode in each of the first sub pixel and the second sub pixel on the substrate, an organic layer with P-type polarity or N-type polarity on the first electrode, and a second electrode on the organic layer. The organic layer provided in the first sub pixel and the organic layer provided in the second sub pixel are spaced apart from each other with a doping layer provided in the boundary area between the first sub pixel and the second sub pixel. The doping layer is doped with dopant whose polarity is opposite to that of the organic layer.

An electroluminescent display device is disclosed. The electroluminescent display device includes a substrate having thereon a first sub pixel and a second sub pixel, a first electrode in each of the first sub pixel and the second sub pixel on the substrate, an organic layer with P-type polarity or N-type polarity on the first electrode, and a second electrode on the organic layer. The organic layer provided in the first sub pixel and the organic layer provided in the second sub pixel are spaced apart from each other with a doping layer provided in the boundary area between the first sub pixel and the second sub pixel. The doping layer is doped with dopant whose polarity is opposite to that of the organic layer.

A method of preparing a quantum dot, a quantum dot prepared by the method, an optical member including the quantum dot, and an apparatus including the quantum dot. The quantum dot may include: a core including a III-V compound; a first shell surrounding the core and including ZnSe; a second shell surrounding the first shell and including ZnSe.sub.1-xS.sub.x, wherein x may be a real number greater than 0 and smaller than 1; and a third shell surrounding the second shell and including ZnS. The method may include: forming the first shell from a first material including zinc and a second material including selenium in a solution; forming the second shell by adding to the solution a third material including zinc and a fourth material including selenium and sulfur; and forming the third shell by adding to the solution a fifth material including zinc.

A light emitting device includes a metal reflective layer including a phase modulation surface on which oblong phase modulation elements are formed; a first electrode provided on the metal reflective layer; an organic emission layer that is provided on the first electrode and that emits light; and a second electrode provided on the organic emission layer, wherein the oblong phase modulation elements are arranged to form a geometric phase lens.

The present disclosure provides an organic electroluminescence device. It includes a substrate; an array of TFTs provided on the substrate; an organic electroluminescence layer provided on the array of TFTs; a light filter layer; wherein an optical film layer is provided between the light filter layer and the organic electroluminescence layer, and has a periodically uneven surface structure made of nano-particles.

A light-emitting device and an electronic apparatus including the same are disclosed. The light-emitting device, includes: a first electrode; a second electrode facing the first electrode; and an interlayer arranged between the first electrode and the second electrode, wherein the interlayer includes a first emission layer and a second emission layer, the first emission layer includes a first compound that emits a first light having a first spectrum, the second emission layer includes a second compound that emits a second light having a second spectrum, the first compound includes a first transition metal, the second compound includes a second transition metal, the first transition metal and the second transition metal are different from each other, |HOMO(1)−HOMO(2)| is about 0.05 eV to about 0.4 eV, and |λmax(1)−λmax(2)| is about 0 nm to about 30 nm, wherein HOMO(1), HOMO(2), λmax(1), and λmax(2) are as described herein.

A light-emitting device and an electronic apparatus including the same are disclosed. The light-emitting device, includes: a first electrode; a second electrode facing the first electrode; and an interlayer arranged between the first electrode and the second electrode, wherein the interlayer includes a first emission layer and a second emission layer, the first emission layer includes a first compound that emits a first light having a first spectrum, the second emission layer includes a second compound that emits a second light having a second spectrum, the first compound includes a first transition metal, the second compound includes a second transition metal, the first transition metal and the second transition metal are different from each other, |HOMO(1)−HOMO(2)| is about 0.05 eV to about 0.4 eV, and |λmax(1)−λmax(2)| is about 0 nm to about 30 nm, wherein HOMO(1), HOMO(2), λmax(1), and λmax(2) are as described herein.

A display device including a lower electrode layer including a first lower electrode having first and second areas, and a second lower electrode having third and fourth areas; a pixel defining layer covering the second and fourth areas; a first electroluminescent layer having an outline substantially surrounding an outline of the first area; a second electroluminescent layer having an outline substantially surrounding an outline of the third area; an upper electrode having an outline substantially surrounding the outlines of the first and second electroluminescent layers; and a color filter layer including a first color filter having an area of which an outline thereof is between the outline of the first area and the outline of the first electroluminescent layer; and a second color filter having an area of which an outline thereof is between the outline of the third area and the outline of the second electroluminescent layer.

A display device may include a display panel and an input sensor. Mesh lines of the input sensor may include first mesh lines extending in a first direction and second mesh lines extending in a second direction crossing the first direction. The first mesh lines and the second mesh lines may cross each other at a plurality of cross points. In a unit region of the sensing electrode, first cutting points may be defined in the first mesh lines and the second mesh lines, and second cutting points may be defined in the first mesh lines and the second mesh lines.