It’s official: quantum dots (QDs) are transforming the way we live. Don’t just take our word for it – ask the Nobel committee, which earlier this year awarded the Nobel Prize for Chemistry to the three scientists behind the discovery and development of this ground-breaking technology. 

But why were QDs nominated in the first place? 

In October, chemists Moungi Bawendi and Louis Brus, and physicist Alexei Ekimov, were jointly awarded the prize for their foundational work on QDs by the Royal Swedish Academy of Sciences. These three men are pioneers of nanotechnology and their contribution to the field cannot be overstated. Thanks to their work, businesses like Quantum Science can continue pushing the boundaries of what QDs can achieve with our INFIQ® infrared QD technology. 

The Nobel committee’s recognition however does not just consider the past accomplishments of scientists, it also considers how a discovery may be used in the future. This acknowledgement of QD’s potential to revolutionise the world around us, unlocking exciting new applications for everything from machine vision cameras to commercial devices, is a testament to what this technology can achieve. 

Colloidal QDs are nanoscale semiconductor particles capable of absorbing and emitting different wavelengths of light. They are small enough that they are subject to the quantum confinement effect. Put simply, as a particle gets smaller, the higher the energy band gap it is subject to. Tuning this band gap by controlling the size of a QD grants the ability to precisely tune the wavelengths of light that it emits or absorbs.  

This high tuneability is the secret to QD technology. Before the discovery of QDs, scientists had been aware that the size of a material affected its properties but were unable to replicate this in quantum materials. Ekimov and Brus were the first to show that this could in fact be achieved. Working independently, Ekimov discovered that adding copper chloride to glass resulted in tiny crystals that changed colour depending on crystal size. Meanwhile, Brus noted that the optical properties of cadmium sulphide particles changed when the size of the crystals changed. 

It was Bawendi who first developed a process for precisely controlling QD growth, and as a result, scientists were able to begin working on unlocking the exciting applications that these nanomaterials make possible. 

Accurate control over the colour of emitted light is useful for display applications like in television screens. QDs can be added to films, filters, glass and electronics used in LCD displays to produce bright, vibrant images. However, the true potential of QD technology lies beyond visible light – in the realm of the infrared. 

Short-wave infrared (SWIR) light represents the next frontier in terms of image sensor technology. At wavelengths from 1,000nm to around 3,000nm, light is not visible to the human eye but acquires some unique properties; effectively, it can be used to ‘see’ beyond the visible spectrum.  

For example, sensors equipped with SWIR-sensitive QD technology are visible through sealed containers, meaning they can be used to monitor fill levels, or are reflected by certain plastics enabling better waste sorting and recycling. At certain wavelengths, SWIR light is highly absorbed by water, producing images that appear black where moisture is detected, which lets cameras detect spoiled food or ice on the roads for example. SWIR light is also not affected by dust, fog, and precipitation, meaning it can be used for security cameras or vehicle sensors regardless of conditions.  

The Nobel committee particularly noted the potential use cases for QDs in medical devices. When used to map biological tissue, the brighter fluorescence of QDs offers enhanced performance compared with other fluorescent tags. 

In all these applications, there is not functional alternative to SWIR, and QDs like our INFIQ® infrared QD technology are uniquely placed to provide this. INFIQ® QDs are tuneable to wavelengths from 800nm to 2,400nm and above, spanning large sections of the SWIR and near-infrared spectra. Unlike other SWIR sensing technologies, they are cheap to produce while still offering outstanding performance, making SWIR capability much more accessible to a wide range of markets. 

And as QD technology advances, the applications it can be used for will significantly expand. Earlier this year, we announced the achievement of lead-free INFIQ® QDs sensitive to 1,550nm. This is a level of performance unmatched elsewhere in the industry for lead-free materials, and means that soon, high performance QD sensors will be available for consumer devices, where restrictions on the use of lead have so far kept the technology out of use. 

All of this is only scratching the surface of what INFIQ® infrared QD technology is capable of. From revolutionising machine vision by empowering artificial intelligence, to enabling solar panels to capture and convert more light into clean energy, these nanoscale semiconductor particles are changing the world. As the technology pioneered in the 1980s advances further, even more applications will become available – and the true potential of QDs will come to light.  

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