Silicon quantum dots under UV light. Source: Fuji PigmentFuji Pigment Co., Ltd. claims that for the first time it has established a large scale commercialization process for the production of silicon quantum dots.

Dr. Ryohei Mori, a researcher at Fuji Pigment, developed the process that is seen as the next-generation of quantum dots because silicon contains no toxicity and the light to electricity conversion efficiency is enhanced in applications such as a solar cell.

Quantum dots are very powerful, yet very thin nanoparticles that have the ability to convert light to nearly any color in the visible spectrum with very high efficiency. The electronic characteristics of quantum dots can be are determined by quantum confinement effect depending on the material’s chemical composition, size and shape.

Control of the color of light given off by a quantum dot can be accomplished by changing its size. Bigger dots emit longer wavelengths, such as red, while smaller dots emit shorter wavelengths such as green or blue.

This has led to the belief that quantum dots could potentially be used in solar cells, smartphones, security tags, sensors, lasers, transistors, photonic crystals, cancel cell imaging, thermoelectric materials, quantum dot computers, artificial photosynthesis or light emitting diodes (LEDs).

The problem is that many quantum dots are made of expensive and toxic heavy metals, especially cadmium, selenium and lead. Developing toxic metal-free quantum dots is seen as a fundamental necessity to grow the market for these nanoparticles.

Mori has previously demonstrated large scale production or carbon quantum dots and graphene quantum dots, however, silicon quantum dots exhibit visible and infrared emission lights simultaneously. Currently, the quantum yield is above 30 percent, but Mori is working to improve the efficiency.