Disclosed are quantum dots based on a graded multishell structure and a method of manufacturing the same. More particularly, each of the quantum dots according to an embodiment of the present invention includes a core, inter shells surrounding the core, and an outer shell surrounding the inter shells, wherein the concentrations of compounds composing the inter shells are changed stepwise from the core to the outer shell.

The present disclosure relates to a nanomaterial, a light-emitting diode device, and a preparation method thereof. The nanomaterial includes a ZnO nanoparticle and an In.sub.2O.sub.3 shell layer covering a surface of the ZnO nanoparticle. In the present disclosure, the In.sub.2O.sub.3 shell layer are coated on the surface of the ZnO nanoparticle to form a ZnO@ In.sub.2O.sub.3 core shell structure, that is, prepare the nanomaterial. In the present disclosure, In.sub.2O.sub.3 having a wide bandgap is used as a shell layer to cover a semiconductor ZnO nanoparticle having a relatively narrow bandgap, which can effectively passivate the surface of the ZnO nanoparticle to reduce the surface defects and relieve lattice mismatch. Meanwhile, holes may be effectively blocked from being transported from a light-emitting layer to a cathode to improve the recombination efficiency of electrons and holes on the light-emitting layer. Thus, the light-emitting performance of the light-emitting device may be improved.

A method of manufacturing of an ink (100) composition comprises a biphasic ligand exchange process. A first phase liquid (10) comprising a nonpolar solvent (11) with a colloidal suspension of nanoparticles (1) that are capped with a shell of non polar ligands (2) is contacted with a second phase liquid (20) comprising a polar solvent (21) with second ligand (3). The second ligand comprises at least one surface binding head group that has an affinity for binding to the nanoparticle; and an ionically charged tail group. The second ligands displace the first ligands to form a dispersion of the nanoparticles that are capped with a shell of the second ligands in the second phase liquid. The nanoparticles can be separated from the second phase liquid. The separated nanoparticles can be (re)dispersed in a printable liquid medium, e.g. used for printing a photoactive layer.

The present invention is directed to methods of preparing metal sulfide, metal selenide, or metal sulfide/selenide nanoparticles and the products derived therefrom. In various embodiments, the nanoparticles are derived from the reaction between precursor metal salts and certain sulfur- and/or selenium-containing precursors each independently having a structure of Formula (I), (II), or (III), or an isomer, salt, or tautomer thereof, where Q.sup.1,Q.sup.2,Q.sup.3,R.sup.1,R.sup.2,R.sup.3,R.sup.5, and X are defined within the specification.

A quantum dot having a perovskite crystal structure and including a compound represented by Chemical Formula 1:
ABX.sub.3+α  Chemical Formula 1
wherein, A is a Group IA metal selected from Rb, Cs, Fr, and a combination thereof, B is a Group IVA metal selected from Si, Ge, Sn, Pb, and a combination thereof, X is a halogen selected from F, Cl, Br, and I, BF.sub.4, or a combination thereof, and α is greater than 0 and less than or equal to about 3; and wherein the quantum dot has a size of about 1 nanometer to about 50 nanometers.

Light emitting devices and LED-filaments comprise an excitation source (e.g. LED) and a photoluminescence material comprising a combination of a first narrow-band red photoluminescence material which generates light with a peak emission wavelength in a range 580 nm to 628 nm and a full width at half maximum emission intensity in a range 45 nm to 60 nm and a second narrow-band red photoluminescence material generates light with a peak emission wavelength in a range 628 nm to 640 nm and a full width at half maximum emission intensity in a range 5 nm to 20 nm. At least one of the first and second narrow-band red photoluminescence materials can comprise a narrow-band red phosphor or a quantum dot (QD) material.

The present application discloses a manufacturing method of an optical film and the optical film. The manufacturing method includes: step S10, mixing titanium source precursors and a barium source and adding an alkaline agent for a reaction to obtain nanoparticles; and step S20, mixing quantum dots, an organic adhesive, and the nanoparticles followed by coating to obtain the optical film.

A device includes chalcogenide nanoparticles and a light-sensitive material configured to absorb upconverted light generated by the chalcogenide nanoparticles. A method includes receiving, at chalcogenide nanoparticles, input light having a first wavelength; and upconverting the input light using the chalcogenide nanoparticles, to generate output light having a second wavelength, in which the second wavelength is less than the first wavelength. A device includes a transparent material, the transparent material being transparent to at least one of infrared light and visible light, and chalcogenide nanoparticles embedded in the transparent material.

Common approaches to synthesizing alloyed quantum dots employ high-cost, air-sensitive phosphine complexes as the selenium precursor. Disclosed quantum dot synthesis embodiments avoid these hazardous and air-sensitive selenium precursors. Certain embodiments utilize a combination comprising a thiol and an amine that together reduce and complex the elemental selenium to form a highly reactive selenium precursor at room temperature. The same combination of thiol and amine acts as the reaction solvent, stabilizing ligand, and sulfur source in the synthesis of quantum dot cores. A non-injection approach may also be used. The optical properties of the quantum dots synthesized by this new approach can be finely tuned for a variety of applications by controlling size and/or composition of size and composition. Further, using the same approach, a shell can be grown around a quantum dot core that improves stability, luminescence efficiency, and may reduce toxicity.

The object of the present invention is to provide an oxide-based phosphor comprising elements other than rare earth elements as light-emitting elements, with low material costs, while achieving high luminous efficacy. The means for achieving the object is a phosphor comprising the following (1) to (3): (1) zirconium oxide, (2) titanium, and (3) at least one element selected from the group consisting of phosphorus, selenium, boron, and silicon.