Abstract: Niobium oxide particles which have a controlled crystal shape and exhibit excellent characteristics are provided. The niobium oxide particles include molybdenum. The niobium oxide particles preferably have a polyhedral, columnar or acicular shape. The MoO3 content (M1) measured by XRF analysis of the niobium oxide particles is preferably 0.1 to 40 mass % relative to the niobium oxide particles taken as 100 mass %. A method for producing the niobium oxide particles described above includes calcining a niobium compound in the presence of a molybdenum compound.

Abstract: It relates to tantalum oxide particles containing molybdenum. The tantalum oxide particles preferably have a polyhedral shape, and the crystallite size of the tantalum oxide particles at 2?=22.8° is preferably 160 nm or more. It also relates to a method for producing the tantalum oxide particles, the method including firing a tantalum compound in the presence of a molybdenum compound.

Abstract: Provided is a composite including copper nanoparticles or copper(I) oxide nanoparticles and a thioether-containing organic compound represented by X(OCH2CHR1)nOCH2CH(OH)CH2SZ [X represents an alkyl group; R1 represents a hydrogen atom or a methyl group; n represents an integer of 2 to 100; R1 is independent between repeating units and may be the same or different; and Z represents an alkyl group, an allyl group, an aryl group, an arylalkyl group, —R2—OH, —R2—NHR3, or —R2—(COR4)m (where R2 represents a saturated hydrocarbon group; R3 represents a hydrogen atom, an acyl group, an alkoxycarbonyl group, or a benzyloxycarbonyl group; R4 represents a hydroxy group, an alkyl group, or an alkoxy group; and m represents 1 to 3)].

Abstract: Provided is a composite including copper nanoparticles or copper(I) oxide nanoparticles and a thioether-containing organic compound represented by X(OCH2CHR1)nOCH2CH(OH)CH2SZ [X represents an alkyl group; R1 represents a hydrogen atom or a methyl group; n represents an integer of 2 to 100; R1 is independent between repeating units and may be the same or different; and Z represents an alkyl group, an allyl group, an aryl group, an arylalkyl group, —R2—OH, —R2—NHR3, or —R2—(COR4)m (where R2 represents a saturated hydrocarbon group; R3 represents a hydrogen atom, an acyl group, an alkoxycarbonyl group, or a benzyloxycarbonyl group; R4 represents a hydroxy group, an alkyl group, or an alkoxy group; and m represents 1 to 3)].

Abstract: Provided are a composite of nanoparticles of a metal such as gold, silver, a platinum metal, or copper, and a polymer, the composite allowing formation of a metal film having a sufficiently low resistivity in terms of practicality simply by drying at room temperature without requiring any special heating-baking step or any step of removing a protective agent with a solvent; a dispersion liquid of the composite; methods for producing the foregoing; and a plastic substrate formed from the dispersion liquid. The composite comprises a (meth)acrylic-based copolymer having, as side chains, a polyethylene glycol chain and a phosphate residue represented by —OP(O)(OH)2 and having, at at least one end of the molecular chain, —SR (where R represents an alkyl group or the like).

Abstract: Provided are a composite of nanoparticles of a metal such as gold, silver, a platinum metal, or copper, and a polymer, the composite allowing formation of a metal film having a sufficiently low resistivity in terms of practicality simply by drying at room temperature without requiring any special heating-baking step or any step of removing a protective agent with a solvent; a dispersion liquid of the composite; methods for producing the foregoing; and a plastic substrate formed from the dispersion liquid. When a dispersion liquid of a metal-nanoparticle-containing composite that is prepared by reducing metal ions in an aqueous medium in the presence of a (meth)acrylic-based copolymer having, as side chains, a polyethylene glycol chain and a phosphate residue represented by —OP(O)(OH)2 and having, at at least one end of the molecular chain, —SR (where R represents an alkyl group or the like), is applied to a base material and is then just dried at room temperature, a film having conductivity is formed.