Described are devices, such as light emitters, lasers, and switches, and methods, such as methods of generating photoluminescence and methods of fabricating electronic devices. Example devices and methods described include those comprising or employing optically active graphene, such as in the form of one or more layers of quasi-1D graphene nanomaterials or graphene nanostripes including one or more topological defects. Optically active graphene can emit photoluminescence upon exposure to photoexcitation and can also generate laser emission, optionally as a frequency comb. The optically active graphene can be patterned onto substrates according to the disclosed methods of fabricating electronic devices and is optionally useful for generating optical switches.

The present invention relates to a negative electrode active material including a silicon-based core particle and an outer carbon coating layer formed on the silicon-based core particle, wherein the outer carbon coating layer contains graphene having a D/G ratio of 0.35 or less in the Raman spectrum.

A light-modulating material of which the light transmittance can be controlled over a wide region from visible light to infrared light by voltage application is provided. The light-modulating material comprises a graphene-like carbon material having an aspect ratio of 3 or more and 330 or less.

A coating layer for a substrate includes a coating material. The coating material includes graphene and/or graphene derivatives that reflect and/or absorb an electromagnetic (EM) wave having a frequency of above 20 GHz. The coating layer is deposited on a surface of the substrate.

A coating layer for a substrate includes a coating material. The coating material includes graphene and/or graphene derivatives that reflect and/or absorb an electromagnetic (EM) wave having a frequency of above 20 GHz. The coating layer is deposited on a surface of the substrate.

Provided is a method of producing multiple isolated hollow graphene balls, comprising: (a) mixing multiple particles of a graphitic material and multiple particles of a solid polymer carrier material to form a mixture in an impacting chamber of an energy impacting apparatus; (b) operating the energy impacting apparatus to peel off graphene sheets from the graphitic material and transferring the graphene sheets to surfaces of solid polymer carrier material particles to produce graphene-coated polymer particles; (c) recovering the graphene-coated polymer particles from the impacting chamber; and (d) suspending the graphene-encapsulated polymer particles in a gaseous medium to keep the particles separated from each other while concurrently pyrolyzing the particles to thermally convert polymer into pores and carbon, wherein at least one of the graphene balls comprises a hollow core enclosed by a shell composed of graphene sheets bonded together by carbon.

Described herein are methods for continuous production of an exfoliated two-dimensional (2D) material comprising passing a 2D material mixture through a convergent-divergent nozzle, the 2D material mixture comprising a 2D layered material and a compressible fluid. The method of the present disclosure employs physical compression and expansion of a flow of high-pressure gases, leaving the 2D layered material largely defect free to produce an exfoliated 2D layered in a simple, continuous, and environmentally friendly manner.

Described herein are methods for continuous production of an exfoliated two-dimensional (2D) material comprising passing a 2D material mixture through a convergent-divergent nozzle, the 2D material mixture comprising a 2D layered material and a compressible fluid. The method of the present disclosure employs physical compression and expansion of a flow of high-pressure gases, leaving the 2D layered material largely defect free to produce an exfoliated 2D layered in a simple, continuous, and environmentally friendly manner.

A solution is prepared that contains (A) a polymer compound that includes at least one of a hydrolyzable polymer compound or a thermally-decomposable polymer compound, (B) an oxoacid-based compound that includes at least one of a phosphate-based compound, a sulfate-based compound, a sulfonate-based compound, or a perchlorate-based compound, and (C) a laminate of layered substances, and the solution is irradiated with at least one of sonic waves or radio waves, or the solution is heated.

Nanoplatelets are prepared from a 3D layered material by: providing a dispersion of the 3D layered material, pressurising the dispersion, rapidly depressurising the dispersion to create shear forces that exfoliate the 3D layered material into nanoplatelets; and/or providing a dispersion of the 3D layered material, forming a first flow of the dispersion along a first flowpath in a first direction, forming a second flow of the dispersion along a second flowpath in a second direction by reversing the first flow or by forming the second flow in a second flowpath, wherein the second flowpath is substantially reverse and non-coaxial with the first flowpath, whereby shear forces between material in the first flowpath and material in the second flowpath exfoliate the 3D layered material into nanoplatelets. Also provided are apparatuses for carrying out the invention and nanoplatelets obtained by the invention.