A method for forming CsPbBr.sub.3 perovskite nanocrystals into a two-dimensional (2D) nanosheet includes providing CsPbBr.sub.3 perovskite nanocrystals; mixing the CsPbBr.sub.3 perovskite nanocrystals into a mixture of a first solvent and a second solvent, to form a solution of the CsPbBr.sub.3 perovskite nanocrystals, the first solvent, and the second solvent; and forming an optoelectronic device by patterning the CsPbBr.sub.3 perovskite nanocrystals into a nanosheet, between first and second electrodes. The first solvent is selected to evaporate before the second solvent.

Composite particles may be produced by drying slurries containing silica particles and graphenic carbon particles in a liquid carrier. Elastomeric formulations comprising a base elastomer composition and the silica-graphenic carbon composite particles are also disclosed. The formulations possess favorable properties such as increased stiffness and are useful for many applications such as tire treads.

Described herein is a nanocrystalline ferrite having the formula Ni.sub.1−x−yM.sub.yCo.sub.xFe.sub.2+zO.sub.4, wherein M is at least one of Zn, Mg, Cu, or Mn, x is 0.01 to 0.8, y is 0.01 to 0.8, and z is −0.5 to 0.5, and wherein the nanocrystalline ferrite has an average grain size of 5 to 100 nm. A method of forming the nanocrystalline ferrite can comprise high energy ball milling.

Disclosed herein are porous electrochromic niobium oxide films comprising a plurality of niobium oxide nanocrystals, wherein the plurality of niobium oxide nanocrystals comprise niobium oxide having a formula of NbO.sub.x where x represents the average Nb:O ratio in the niobium oxide and where x is from 2 to 2.6. Also disclosed herein are methods of making the porous electrochromic niobium oxide films, methods of use of the porous electrochromic niobium oxide films, and devices comprising the porous electrochromic niobium oxide films.

The introduction of graphene as a carrier for enzymes and catalysts is disclosed.

The present invention provides a metal-carbon composite of a core-shell structure and a method of synthesizing the same. The method includes preparing a first polymer-covered glass substrate with a nano-thickness metal film deposited thereon; immersing the first polymer-covered glass substrate with the metal film to delaminate one or more 2D freestanding organic-metal nanosheets from the first polymer-covered glass substrate; transferring the one or more 2D freestanding organic-metal nanosheets onto a second target substrate; and annealing the one or more 2D freestanding organic-metal nanosheets to decompose an organic portion of the organic-metal nanosheet into an amorphous carbon-containing shell forming a metal-carbon nanocomposite of a core-shell structure.

In one aspect of the invention, a dye sensitized solar cell has a counter-electrode including carbon-titania nanocomposite thin films made by forming a carbon-based ink; forming a titania (TiO.sub.2) solution; blade-coating a mechanical mixture of the carbon-based ink and the titania solution onto a substrate; and annealing the blade-coated substrate at a first temperature for a first period of time to obtain the carbon-based titania nanocomposite thin films. In certain embodiments, the carbon-based titania nanocomposite thin films may include solvent-exfoliated graphene titania (SEG-TiO.sub.2) nanocomposite thin films, or single walled carbon nanotube titania (SWCNT-TiO.sub.2) nanocomposite thin films.

A composition for reducing the detectable cross-section of an object, which includes graphite selected from the group consisting of graphite flakes, particles of exfoliated graphite, graphitic nano-structures, and combinations of one or more thereof, wherein the graphite is dispersed in a coating composition. Also included are objects to which the composition are applied, and a process for reducing the detectable cross-section of an object.

A method of forming a composition having exfoliated nanoplatelets functionalized with covalently bound surface-modifiers, includes exfoliating a layered nanoclay is exfoliated with a surfactant. The method also includes reacting the exfoliated layered nanoclay with a surface modifier comprising one or more of an epoxide, a silane, or an isocyanate.

The invention provides Y.sub.2O.sub.3:RE nanoparticles having a cubic crystal structure, wherein RE is a trivalent rare earth metal ion. The invention further provides a method of preparing Y.sub.2O.sub.3:RE nanoparticles, comprising: a) providing a mixture comprising (i) an yttrium salt and/or yttrium alkoxide, (ii) a rare earth metal salt and/or rare earth metal alkoxide, and (iii) an organic solvent; b) optionally, subjecting the mixture to a pre-treatment step which comprises heating the mixture at a temperature of at least 80° C. and/or at a temperature such that crystal water and/or organic impurities are removed, c) heating the mixture at a temperature between 220° C. and 320° C. and/or at a temperature such that a precursor complex forms; d) subjecting the mixture to a precipitation stage, wherein a precipitate forms, said precipitation stage preferably comprising allowing the mixture to cool and/or adding an antisolvent to the mixture; and e) heating the precipitate at a temperature between 600° C. and 900° C. and/or at a temperature such that a cubic Y.sub.2O.sub.3 crystal structure forms, preferably for at least 10 minutes.