Shrink graphene to nano,
and it goes quantum.
What is a Graphene Quantum Dot?
The graphene quantum dot (GQD) is the core material of GranovaQ®. It is graphene reduced to nanometer-sized particles that show the quantum size effect. By controlling particle size, we can tune the material for each application.
01 / Three features
Why GQD?
GQD differs from conventional graphene and metal-oxide nanoparticles in three ways. The quantum size effect, the graphene structure and high dispersibility together make it a versatile functional material.
Feature · 01
Quantum size effect
When particles shrink to the nanometer scale, electrons start to behave according to quantum mechanics. Because the band gap depends on particle size, choosing a 10, 20 or 50 nm grade lets us tune the material's properties.
Feature · 02
Graphene structure
Graphene is a single sheet of carbon atoms arranged in a hexagonal lattice, with very high electron mobility, thermal conductivity and mechanical strength. GQD is graphene cut down into nanometer-sized particles.
Feature · 03
High dispersibility
Smaller particles have a larger specific surface area and disperse more evenly in formulations and fibers. They also keep the material transparent, so GQD works in cosmetic formulations and light-colored fibers.
02 / The physics
It starts with the quantum size effect.
Ordinary, macro-scale graphene has no band gap: it is a zero-gap semimetal. Its electrons move with a linear dispersion near the Dirac point, so it absorbs light across a broad band from visible to near-infrared, with little selectivity for particular wavelengths.
When graphene is cut into nanoparticles of 50 nm or less, the electrons are confined in space and a band gap opens through the quantum confinement effect. The band gap Eg scales roughly as Eg ∝ 1/d² with particle size d, so controlling particle size directly tunes the optical and electronic properties.
This is the same physical principle as in semiconductor nanocrystals such as CdSe quantum dots. The decisive difference is that GQD achieves it with a carbon-based material free of heavy metals. GQDs are generally known to have an absorption edge in the visible to near-ultraviolet range, depending on particle size.
Particle size also affects how GQD emits light. GQDs show size-dependent photoluminescence (fluorescence), and like graphene they conduct heat well and emit far-infrared radiation. Being able to set these properties by choosing the particle size is what makes GQD useful as a functional material.
In fibers, GQD is kneaded into the fiber itself, not coated on the surface. It is not an additive that is released gradually, it contains no metals, and it stays in the fiber. That is why its performance is long-lasting and resistant to washing.
03 / Functions and the material
Functions that last.
The five functions marketed in Japan — antibacterial and odor-resistant, antiviral, anti-mite, anti-mold and far-infrared — and the physical process and particle-size control behind them. Here is why GranovaQ GQD keeps working over time.
Detail · 01
Antibacterial and odor-resistant: bound into the fiber
Inhibits the growth of specific bacteria on the fiber, helping to prevent odor.
In Japan, fibers containing GranovaQ GQD are marketed as antibacterial and odor-resistant. GQD is kneaded into the fiber itself rather than coated on the surface or released over time, so it stays in place and the effect is long-lasting and resistant to washing.
- Function
- Antibacterial, odor-resistant
- Form
- Bound into the fiber
Detail · 02
Antiviral: no leaching, no metals
Reduces specific viruses that adhere to the fiber.
In Japan, fibers containing GranovaQ GQD are marketed as antiviral. GQD is pure carbon and contains no silver, copper or other metals, so there is nothing to leach out of the fiber over time.
- Function
- Antiviral
- Metals
- None
Detail · 03
Anti-mite and anti-mold: for everyday textiles
Helps keep dust mites away and helps prevent mold from growing on the fiber surface.
In Japan, fibers containing GranovaQ GQD are marketed as anti-mite and anti-mold. These functions suit bedding, innerwear and fillings — items used every day that tend to trap humidity. Because GQD is kneaded into the fiber, the effect is resistant to washing.
- Function
- Anti-mite, anti-mold
- Typical uses
- Bedding, innerwear
Detail · 04
Far-infrared: a property of graphene
Emits far-infrared radiation.
Graphene conducts heat well and emits far-infrared radiation. Fibers containing GQD emit far-infrared radiation when warmed by body heat. No electricity or batteries are needed.
- Function
- Far-infrared
- Power
- Not required
Detail · 05
Physical vs. chemical production: residues and crystal structure
Physical exfoliation without strong acids or oxidizers: no chemical residues, intact crystal structure.
Most graphene oxide on the market (GO / rGO) is made by oxidation-reduction processes such as the Hummers method, which can leave residues of strong acids and oxidizers and introduce defects into the crystal structure. GranovaQ GQD is made by a purely physical process (mechanical exfoliation plus particle-size control) and has no chemical residues. It contains no metals, so there is no risk of metal leaching, which makes it a good fit for recovery wear, bedding and cosmetic formulations that stay in contact with the skin for long periods.
- Process
- Purely physical
- Metals
- None
Detail · 06
10 / 20 / 50 nm: three grades for different uses
Optimized for cosmetic formulations (10 nm), fiber blends (20 nm) and bedding and nonwovens (50 nm).
Smaller particles show a stronger quantum size effect, have a larger specific surface area, and disperse more evenly and transparently. GranovaQ offers three grades: 10 nm for cosmetic formulations (transparent; 0.05–0.30% in shampoos and scalp essences), 20 nm for fiber blends (the standard for recovery and sportswear, 0.5–2.0%), and 50 nm for bedding and nonwovens (fillings, ticking and covers, 1.0–3.0%). Particle size affects function, cost and maximum loading, so the grade can be chosen to match each brand's product design.
- Grades
- 10 / 20 / 50 nm
- Loading range
- 0.05–3.0%
The functions above describe the material itself, as marketed in Japan. They are not claims that any product protects people from bacteria, viruses or disease. Claims that may be made for products sold outside Japan depend on local regulations (for example, the U.S. EPA and the EU Biocidal Products Regulation). Please consult us for each market.
04 / Compared with other graphene
How GQD differs from other graphene.
Graphene sheets, graphene oxide and quantum dots behave differently and suit different uses. GranovaQ GQD combines a purely physical process, nanoscale particles and an intact crystal structure, so it blends reliably into the end product.
| Type | Particle size | Characteristics and issues |
|---|---|---|
| Conventional graphene (sheets) | Several µm to several mm | Tends to clump together and is hard to blend into formulations. Difficult to keep transparent. |
| Graphene oxide (GO / rGO) | Several µm | Made by oxidation, so chemical residues (strong acids, oxidizers) can remain. Oxidation introduces defects into the electronic structure. |
| GranovaQ GQD | 10 / 20 / 50 nm | Made by a purely physical process: no chemical residues and an intact crystal structure. Particle size is controlled for each application. |
05 / FAQ
Common questions about graphene quantum dots.
- Q. How is GQD different from conventional quantum dots (QD)?
- A. Conventional quantum dots are made from semiconductors such as cadmium sulfide (CdS) or cadmium selenide (CdSe), which contain heavy metals. GQD replaces them with carbon-based graphene, giving the properties of a quantum dot without the risk of heavy-metal leaching.
- Q. How does GQD relate to nanoparticles (nanomaterials)?
- A. GQD is a type of nanomaterial. Unlike common metal-oxide nanoparticles (such as TiO₂ or ZnO), it also has the electronic properties of graphene, including high electron mobility and the quantum size effect.
- Q. Why three grades: 10, 20 and 50 nm?
- A. Each size was designed for a use: transparency in cosmetic formulations (10 nm), the standard for fiber blends (20 nm), and added strength in bedding and nonwovens (50 nm). Particle size changes the balance between the quantum size effect and other physical properties.
- Q. What patents protect GQD?
- A. We hold 21 patents in China, Japan and other countries, centered on particle-size control by a purely physical process. They include related patents on blending processes, applications and mass production.
- Q. What is the key difference between graphene quantum dots (GQD) and conventional quantum dots (QD)?
- A. Conventional quantum dots are made from heavy-metal semiconductors such as CdSe, CdS and PbS. They show the quantum size effect, but the risk of heavy-metal leaching remains. GQD achieves the quantum size effect with a carbon-based graphene structure, free of heavy metals and chemical additives (purely physical process). The essential difference is that it combines safety with performance.
- Q. Is there a risk of heavy metals (such as cadmium) leaching out?
- A. GranovaQ GQD is made from natural graphite reduced to nanoparticles by a purely physical process. No heavy-metal salts or oxidizers are used in production. Because the material contains no metals, there is no leaching risk of the kind associated with metal-based additives such as silver or copper.
- Q. How is the safety of GQD as a nanomaterial supported?
- A. GQD consists only of carbon and is produced by a purely physical process without chemicals. Some recovery wear made with GQD is notified in Japan as a general medical device. For details on material safety, please contact us.
- Q. How does it compare with other graphene materials?
- A. Mainstream graphene oxide (GO / rGO) is made by chemical processes using strong acids and oxidizers, which can leave chemical residues and introduce defects into the electronic structure. GranovaQ combines a purely physical process with mass production of three grades (10, 20 and 50 nm), giving the consistent quality needed for commercial use. Production is handled by our R&D and manufacturing site in China, which has large-scale capacity.
- Q. How is quality assured for production in China?
- A. Our manufacturing site is located in an industrial cluster for strategic materials designated by the Chinese government. The raw material is natural graphite from a deposit about 160 m underground, and quality is controlled throughout a purely physical mass-production process.
— Next
How is GQDmade?
Next, the production process: a purely physical method with no chemical additives, and mass production at one-tenth the cost.