Provided are an organic-inorganic-hybrid perovskite nanocrystal particle light-emitter having a two-dimensional structure, a method for producing the same, and a light emitting device using the same. The organic-inorganic-hybrid perovskite nanocrystal particle light-emitter having a two-dimensional structure comprises an organic-inorganic-hybrid perovskite nanocrystal structure having a two-dimensional structure which can be dispersed in an organic solvent. Accordingly, the nanocrystal particle light-emitter comprises an organic-inorganic-hybrid perovskite nanocrystal having a crystal structure combining FCC and BCC; forms a lamellar structure where organic planes and inorganic planes are accumulated in an alternating manner; and can exhibit high color purity by confining excitons in the inorganic planes. In addition, since the exciton diffusion distance decreases and exciton binding energy increases, it is possible to prevent exciton annihilation caused by thermal ionization and delocalization of charge carriers, such that the nanocrystal particle light-emitter can have high luminescence efficiency at room temperature.

Provided are perovskite nanocrystalline particle and an optoelectronic device using the same. The perovskite nanocrystalline particle may include a perovskite nanocrystalline structure while being dispersible in an organic solvent. Accordingly, the perovskite nanocrystalline particle in accordance with the present invention has therein a perovskite nanocrystal having a crystalline structure in which FCC and BCC are combined; forms a lamellar structure in which an organic plane and an inorganic plane are alternately stacked; and can show high color purity since excitons are confined to the inorganic plane. In addition, the perovskite nanocrystalline particle have a particle size greater than or equal to a Bohr diameter beyond a quantum confinement effect, and simultaneously can implement high emission efficiency and emission wavelength which is almost not dependent on particle size. Furthermore, the perovskite nanocrystalline particle in accordance with the present invention, as a nanoparticle which is dispersible in an organic solvent, is applicable in various electronic devices such as light emitting devices, lasers, solar cells, etc.

Provided are: a light-emitting layer for a perovskite light-emitting device; a method for manufacturing the same; and a perovskite light-emitting device using the same. The method of the present invention for manufacturing a light-emitting layer for an organic and inorganic hybrid perovskite light-emitting device comprises a step of forming a first nanoparticle thin film by coating, on a member for coating a light-emitting layer, a solution comprising organic and inorganic perovskite nanoparticles including an organic and inorganic perovskite nanocrystalline structure. Thereby, a nanoparticle light emitter has therein an organic and inorganic hybrid perovskite having a crystalline structure in which FCC and BCC are combined; forms a lamella structure in which an organic plane and an inorganic plane are alternatively stacked; and can show high color purity since excitons are confined to the inorganic plane. In addition, it is possible to improve the luminescence efficiency and luminance of a device by making perovskite as nanoparticles and then introducing the same into a light-emitting layer.

The disclosure related to a method for making a nanowire structure. First, a free-standing carbon nanotube structure is suspended. Second, a metal layer is coated on a surface of the carbon nanotube structure. The metal layer is oxidized to grow metal oxide nanowires.

The invention is in the field of nanostructure synthesis. The invention relates to methods for producing nanostructures, particularly Group III-V and Group II-VI semiconductor nanostructures. The invention also relates to high temperature methods of synthesizing nanostructures comprising simultaneous injection of cores and shell precursors.

The disclosure generally relates to a dispersion of nanoparticles in a liquid medium. The liquid medium is suitably water-based and further includes an ionic liquid-based stabilizer in the liquid medium to stabilize the dispersion of nanoparticles therein. The stabilizer can be polymeric or monomeric and generally includes a moiety with at least one quaternary ammonium cation from a corresponding ionic liquid. The dispersion suitably can be formed by shearing or otherwise mixing a mixture/combination of its components. The dispersions can be used to form nanoparticle composite films upon drying or otherwise removing the liquid medium carrier, with the stabilizer providing a nanoparticle binder in the composite film. The films can be formed on essentially any desired substrate and can impart improved electrical conductivity and/or thermal conductivity properties to the substrate.

The present invention is directed to methods of transferring urea from an aqueous solution comprising urea to a MXene composition, the method comprising contacting the aqueous solution comprising urea with the MXene composition for a time sufficient to form an intercalated MXene composition comprising urea.

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.

The present disclosure relates to a composition that includes a particle and a surface species, where the particle has a characteristic length between greater than zero nm and 100 nm inclusively, and the surface species is associated with a surface of the particle such that the particle maintains a crystalline form when the composition is at a temperature between −180° C. and 150° C.

The present disclosure relates to a method of preparing a graphene metal nanoparticle-composite, including: preparing graphene by applying a shearing force to a first solution containing a graphite-based material and thus exfoliating the graphite-based material; preparing metal nanoparticles by applying a shearing force to a second solution containing a metal precursor, a capping agent, and a reducing agent; and physically combining the metal nanoparticles on the graphene by applying a shearing force to a third solution containing the graphene and the metal nanoparticles, and a graphene metal nanoparticle-composite prepared according to the method.