The objective is to provide an organic electroluminescent element with an improved luminous efficiency. The organic electroluminescent element has a structure in which a first light-emitting unit containing a phosphorescent red light-emitting material, a second light-emitting unit containing a phosphorescent yellow light-emitting material, and a third light-emitting unit containing a fluorescent blue light-emitting material are stacked with interlayers in-between. A peak emission wavelength of the phosphorescent yellow light-emitting material is in a range of 530 nm to 570 nm. A peak emission wavelength of the fluorescent blue light-emitting material is in a range of 440 nm to 480 nm. The organic electroluminescent element has a ratio of a yellow emission intensity to a blue emission intensity in a range of 1.0 to 2.0. The organic electroluminescent element further has a ratio of a red emission intensity to the blue emission intensity in a range of 1.5 to 3.0.

Disclosed is a composite particle including a plurality of nanoparticles encapsulated in an inorganic material, wherein the plurality of nanoparticles is uniformly dispersed in the inorganic material. Also disclosed is relates to a light emitting material, a support supporting at least one composite particle and/or a light emitting material and an optoelectronic device including at least one composite particle and/or a light emitting material.

Provided is a hybridized perovskite quantum dot material. The quantum dot material comprises a kernel and surface ligands. The kernel is formed by R.sub.1NH.sub.3AB.sub.3 or (R.sub.2NH.sub.3).sub.2AB.sub.4, where R.sub.1 is methyl group, R.sub.2 is an organic molecular group, A is at least one selected from Ge, Sn, Pb, Sb, Bi, Cu and Mn, B is at least one selected from Cl, Br and I, A and B form a coordination octahedral structure, and R.sub.1NH.sub.3 or R.sub.2NH.sub.3 is filled in gaps of the coordination octahedral structure. The surface ligand is an organic acid or organic amine. The quantum dot material has a high fluorescence quantum yield.

In one aspect, organic-inorganic nanoparticle compositions are described herein comprising engineered surfaces which, in some embodiments, reduce non-radiative recombination mechanisms, thereby providing optoelectronic devices with enhanced efficiencies. In some embodiments, a nanoparticle composition comprises a layer of organic-inorganic perovskite nanocrystals, the organic-inorganic perovskite nanocrystals comprising surfaces associated with growth passivation ligands and trap passivation ligands, wherein the growth passivation ligands are larger than the trap passivation ligands and are of size unable to incorporate into octahedral corner sites of the perovskite crystal structure.

There is provided a method of preparing formamidinium lead halide perovskite quantum dots having a photoluminescence quantum yield higher than before. The disclosed method comprises steps of: preparing a lead halide solution by dissolving lead halide (II), oleic acid and oleylamine in a nonpolar solvent; preparing a formamidinium solution by dissolving formamidine acetate salt and oleic acid in a nonpolar solvent; mixing the formamidinium solution and the lead halide solution to form quantum dots; and centrifuging the mixed solution to obtain sediment; dispersing the sediment in a nonpolar solvent to prepare a crude quantum dot solution; mixing the crude quantum dot solution with methyl acetate; and centrifuging the crude quantum dot solution mixed with the methyl acetate to obtain sediment as purified quantum dots. The durable quantum dots are stably formed by injecting the lead halide solution into the formamidinium solution heated at 60° C.-90° C.

Provided are a core-shell structured perovskite particle light-emitter, a method of preparing the same, and a light emitting device using the same. The core-shell structured perovskite particle light-emitter or metal halide perovskite particle light-emitter has a perovskite nanocrystal structure and a core-shell structured particle structure. Therefore, in the perovskite particle light-emitter of the present invention, as a shell is formed of a substance having a wider band gap than that of a core, excitons may be more dominantly confined in the core, and durability of the nanocrystal may be improved to prevent exposure of the core perovskite to the air using a perovskite or inorganic semiconductor, which is stable in the air, or a polymer.

An object of the present invention is to provide: a curable composition comprising a fluorescent particle containing a perovskite compound, wherein the maintenance rate of the quantum yield after curing the curable composition by photoirradiation to form a cured film relative to the quantum yield before forming the cured film is high; a film formed by curing the curable composition; and a laminated body and a display apparatus comprising the film. Provided are: a curable composition comprising a fluorescent particle (A) containing a perovskite compound, a photopolymerizable compound (B), and a photopolymerization initiator (C), wherein the expression: 5.0×10.sup.−6≤(Ab.sub.C× M.sub.C)/M.sub.A≤1.0 is satisfied, wherein M.sub.A [% by mass] represents the content of the fluorescent particle (A) and M.sub.C [% by mass] represents the content of the photopolymerization initiator (C) in 100% by mass of the solid content of the curable composition, and Ab.sub.C represents the absorbance of the photopolymerization initiator (C) at a wavelength of 365 nm and at a concentration of 1 mg/100 mL; a film formed by curing the curable composition; and a laminated body and a display apparatus comprising the film.

A quantum dot composition includes a quantum dot, and a ligand bonded to a surface of the quantum dot, wherein the ligand includes a head portion bonded to the surface of the quantum dot, a connecting portion connected to the head portion and including a metal, and a tail portion coordinated to the metal of the connecting portion. The quantum dot composition according to the present embodiments is used to form an emission layer of a light emitting element, and may thus increase service life and luminous efficiency of the light emitting element including the emission layer formed using the quantum dot composition.

A quantum dot composition includes a quantum dot having a surface to which a ligand is bonded, and a photoacid generator. The quantum dot composition according to one or more embodiments may be applied to an emission layer of a light emitting element and a display device, thereby improving luminous efficiency of the light emitting element.

A quantum dot composition includes a quantum dot, and a ligand bonded to a surface of the quantum dot, wherein the ligand includes a head portion bonded to the surface of the quantum dot and containing a polar solvent dissociative functional group, and a tail portion connected to the head portion. A quantum dot composition according to an embodiment is used to form an emission layer of a light emitting element to enhance luminous efficiency of the light emitting element including an emission layer formed through the quantum dot composition.