Provided is a method of arranging particles on a substrate, the method including: (a) preparing a substrate, a surface of which has depressions or projections capable of fixing the positions and/or orientations of one or more particles; and (b) placing the particles on the substrate and applying a physical pressure to the particles so that a portion or the whole of each particle is inserted in each of pores defined by the depressions or the projections. Provided is also a method of arranging particles on a substrate, the method including: (a) preparing a substrate, at least a surface portion of which has adhesive property; and (b) placing particles, which do not have flat facets but curved surfaces, on the substrate and applying a physical pressure to the particles so that the particles are immobilized on adhesive surface portions of the substrate.

Improved V.sub.2O.sub.5 materials are disclosed herein in the form of 2D leaf-like nanosheets. Methods of forming the V.sub.2O.sub.5 nanosheets and batteries (e.g., lithium-ion) incorporating the V.sub.2O.sub.5 nanosheets are also provided.

Improved V.sub.2O.sub.5 materials are disclosed herein in the form of 2D leaf-like nanosheets. Methods of forming the V.sub.2O.sub.5 nanosheets and batteries (e.g., lithium-ion) incorporating the V.sub.2O.sub.5 nanosheets are also provided.

A photonic crystal microsphere, comprising: a plurality of mono-dispersed polymer particles in a closely-packed and regularly-ordered structure, with interstition therebetween, forming the photonic crystal microsphere; and a co-assembly material contained in the interstition. The photonic crystal microsphere provides a structure of enhanced strength and a good color effect.

A photonic crystal microsphere, comprising: a plurality of mono-dispersed polymer particles in a closely-packed and regularly-ordered structure, with interstition therebetween, forming the photonic crystal microsphere; and a co-assembly material contained in the interstition. The photonic crystal microsphere provides a structure of enhanced strength and a good color effect.

[Problem] To provide a method for producing a colloidal crystal, wherein the method is easily controlled and is capable of dealing with a wide range of types of colloidal particle. [Solution] The method for producing a colloidal crystal in the present invention is characterized by comprising a preparation step of preparing a colloidal dispersion liquid, in which colloidal particles are dispersed in a liquid comprising an ionic surfactant and a colloidal crystal can be formed due to temperature changes, and a crystallization step of formation of a colloidal crystal by changing the temperature of the colloidal dispersion liquid from a temperature region in which the colloidal crystal is not formed to a temperature region in which the colloidal crystal is formed.

[Problem] To provide a method for producing a colloidal crystal, wherein the method is easily controlled and is capable of dealing with a wide range of types of colloidal particle. [Solution] The method for producing a colloidal crystal in the present invention is characterized by comprising a preparation step of preparing a colloidal dispersion liquid, in which colloidal particles are dispersed in a liquid comprising an ionic surfactant and a colloidal crystal can be formed due to temperature changes, and a crystallization step of formation of a colloidal crystal by changing the temperature of the colloidal dispersion liquid from a temperature region in which the colloidal crystal is not formed to a temperature region in which the colloidal crystal is formed.

A unitary graphene layer or graphene single crystal containing closely packed and chemically bonded parallel graphene planes having an inter-graphene plane spacing of 0.335 to 0.40 nm and an oxygen content of 0.01% to 10% by weight, which unitary graphene layer or graphene single crystal is obtained from heat-treating a graphene oxide gel at a temperature higher than 100 C., wherein the average mis-orientation angle between two graphene planes is less than 10 degrees, more typically less than 5 degrees. The molecules in the graphene oxide gel, upon drying and heat-treating, are chemically interconnected and integrated into a unitary graphene entity containing no discrete graphite flake or graphene platelet. This graphene monolith exhibits a combination of exceptional thermal conductivity, electrical conductivity, mechanical strength, surface smoothness, surface hardness, and scratch resistance unmatched by any thin-film material of comparable thickness range.

A unitary graphene layer or graphene single crystal containing closely packed and chemically bonded parallel graphene planes having an inter-graphene plane spacing of 0.335 to 0.40 nm and an oxygen content of 0.01% to 10% by weight, which unitary graphene layer or graphene single crystal is obtained from heat-treating a graphene oxide gel at a temperature higher than 100 C., wherein the average mis-orientation angle between two graphene planes is less than 10 degrees, more typically less than 5 degrees. The molecules in the graphene oxide gel, upon drying and heat-treating, are chemically interconnected and integrated into a unitary graphene entity containing no discrete graphite flake or graphene platelet. This graphene monolith exhibits a combination of exceptional thermal conductivity, electrical conductivity, mechanical strength, surface smoothness, surface hardness, and scratch resistance unmatched by any thin-film material of comparable thickness range.

A unitary graphene layer or graphene single crystal containing closely packed and chemically bonded parallel graphene planes having an inter-graphene plane spacing of 0.335 to 0.40 nm and an oxygen content of 0.01% to 10% by weight, which unitary graphene layer or graphene single crystal is obtained from heat-treating a graphene oxide gel at a temperature higher than 100 C., wherein the average mis-orientation angle between two graphene planes is less than 10 degrees, more typically less than 5 degrees. The molecules in the graphene oxide gel, upon drying and heat-treating, are chemically interconnected and integrated into a unitary graphene entity containing no discrete graphite flake or graphene platelet. This graphene monolith exhibits a combination of exceptional thermal conductivity, electrical conductivity, mechanical strength, surface smoothness, surface hardness, and scratch resistance unmatched by any thin-film material of comparable thickness range.