For the first time, a large-scale manufacturing process has been developed for carbon and graphene quantum dots. The patent-pending process offers high quantum yields (over 45% for carbon quantum dots and over 80% for graphene quantum dots), representing a breakthrough in quantum dot manufacturing.
Quantum Dots Explained
Quantum dots are semiconductor devices with a typical diameter of 2 to 10 nanometers, too small to be seen with conventional microscopes. The dots are capable of holding electrons in tight confinement, which gives them unique capabilities. For example, the photoluminescence of quantum dots can be controlled, producing light of almost any wavelength in the visible spectrum with high efficiency.
The electronic properties of quantum dots can be tuned by adjusting their chemical composition, size and shape. Larger sizes of dots emit longer wavelengths, while smaller sizes emit shorter wavelengths. The wavelength of light emitted is called the “tune” of the quantum dot. This “tunability" makes quantum dots an ideal candidate for smartphone displays, LEDs and a host of other applications.
Manufacturing Sustainable Quantum Dots
Although there are many types of quantum dots, most are manufactured from semiconductor materials such as cadmium selenide or lead(II) sulfide. However, heavy metals like these are both expensive and toxic, with many being prohibited for industrial use.
Two alternatives to these heavy metal quantum dots are carbon quantum dots (CQDs) and graphene quantum dots (GQDs). These carbon-based materials exhibit comparable optical properties to other quantum dots as well as highly stable photoluminescence. Moreover, carbon-based quantum dots are environmentally friendly and safe to use for biomedical purposes such as bio-imaging, protein analysis, and cell tracking.
With the recent development of a large-scale manufacturing process for CQDs and GQDs by researchers at Fuji Pigment Co., these environmentally-sound alternatives may soon see widespread use.
For more information, visit the Fuji Pigment Co. website.