KAWANISHI-CITY, Japan, April 20, 2016 /PRNewswire/ -- Quantum dots are tiny man-made fluorescent semiconductor nanoparticles (nano-sized crystal) typically between 10 to 10000 atoms (2 to 10 nanometers) in diameter, which is smaller than 1/10000th the width of a human hair. Quantum dots are so small that they cannot be seen with a conventional microscope. To put it simply, quantum dots are incredibly small particles. Yes, on an atomic-scale. However, the effects of this extreme small size cannot be ignored. Quantum dots are actually very powerful devices, and it is their size that gives them unique abilities, including converting light to nearly any color in the visible spectrum with very high efficiency.
The electronic characteristics of quantum dots are determined by their chemical composition, size, and shape. This means that we can control the color of light given off by a quantum dot just by changing its size. Bigger dots emit longer wavelengths, such as red, while smaller dots emit shorter wavelengths, such as green or blue. The tune of a quantum dot is the wavelength of light that it emits. Quantum dots' ability to precisely convert and tune a spectrum of light (e.g. red, green, or blue) makes them ideal for TV displays, smartphones, tablet displays, LEDs, medical experimental imaging, bio-imaging, solar cells, security tags, quantum dot lasers, photonic crystal materials, transistors, thermoelectric materials, various type of sensors and quantum dot computers etc.
Various types of quantum dots currently exist, but in general, quantum dots are made of semiconductor materials such as CdSe, CdS, InP, ZnS, InP/ZnS, CIS (copper indium selenide or sulfide), and PbS. However, these materials are relatively expensive and toxic, especially Cd, Se, and Pb. These toxic heavy metals are unfavorable and occasionally prohibited for use in many industrial areas. Therefore, it is essential to develop toxic metal-free quantum dots, which exhibit a high light emitting quantum efficiency and stability as good as those of the expensive and toxic metal-based quantum dots.
In this regard, Dr. Ryohei Mori at Fuji Pigment Co., Ltd (Kawanishi city, Japan) has been diligently researching and developing inexpensive quantum dots based on safe materials, and has succeeded in developing a large-scale manufacturing process for carbon quantum dots and graphene quantum dots.
Carbon, graphene quantum dots have been proposed as next generation quantum dots. With carbon-based material, quantum dots can be environmentally friendly, safe, and bio-compatible. They can be made from cheap, abundant, and bio-compatible materials such as sugar, glucose, amino acids etc. In addition, as carbon is highly compatible with the human body and any animal and plant living cell, carbon, graphene quantum dots can be applied for bio-imaging, protein analysis, cell tracking, and many other bio-medical applications. For carbon quantum dots, quantum yield exceeds 45% (Dr. Ryohei Mori is still pursuing higher quantum efficiency). Moreover, quantum yield of graphene quantum dot is over 80%!! This is the first time in the world that a large-scale manufacturing process has been developed for carbon and graphene quantum dots with such a high quantum yield.
Fuji Pigment Co., Ltd, has also been commercialized ordinary quantum dots, such as ZnS, ZnSe, CdSe, CIS, InP/ZnS, CIS/ZnS, CdSe, CdS etc…and many others, with large-scale manufacturing processes.
Dr. Ryohei Mori
Company TEL : +81-72-759-8501
SOURCE Fuji Pigment Co.,Ltd.