Lab unlocks potential of quantum dots

Responsible for several important milestones in the study of quantum mechanics, or more specifically quantum dots, the Los Alamos National Laboratory has once more proven to be at the forefront of this field by revealing a plethora of breakthroughs and discoveries.

The findings, published in the journal "Science," covers the nearly three decades of research into quantum dots and assesses the technological progress for these nanometer-sized specks of semiconductive matter, ultimately detailing that by manufacturing quantum dots to the correct "frequency," it could enable an entirely new generation of near-science fiction levels of technology.

"Thirty years ago, these structures were just a subject of scientific curiosity studied by a small group of enthusiasts. Over the years, quantum dots have become industrial-grade materials exploited in a range of traditional and emerging technologies, some of which have already found their way into commercial markets," said Victor Klimov, a coauthor of the paper and leader of the team conducting quantum dot research at Los Alamos National Laboratory.

With the advances discovered by Los Alamos – using colloidal chemistry (the suspension of insoluble particles throughout another substance) – the dimensions and internal structure of quantum dots can be manipulated with near-atomic precision, allowing for highly accurate control of their physical properties and thereby behaviors in practical devices.

By engineering the exact composition of the crystal structure of quantum dots, often referred to as QDs, the researchers at Los Alamos have progressed far beyond its transistor discovery and into the realm of potentially new electronics.

You can read more about the previous breakthrough by Los Alamos, as well as the properties and characteristics of quantum dots at Quantum dot transistor gets green light in the November 11, 2020 edition of Metal Tech News.

As we have seen commercially, the practical applications of QDs by exploited size-controlled tunability of their emissive color have been particularly attractive for screen displays and lighting, e.g., QLED televisions.

According to Los Alamos, the next frontier is creating technologically viable LEDs powered by electrically driven quantum dots. As quantum LEDs have already reached impressive brightness and almost ideal efficiencies near the theoretically defined limits, the next step is to power themselves.

This also opens the gates for something Klimov calls luminescent solar concentrators, or LSCs.

"Using the LSC approach, one can, in principle, convert standard windows or wall sidings into power generating devices. Along with roof-top solar modules, this could help supply an entire building with clean energy. While the LSC concept was introduced back in [the] 1970s, it truly flourished only recently due to the introduction of specially engineered quantum dots."

This, of course, refers to photovoltaics. With the quantum dot approach, a new generation of inexpensive, thin-film PV devices prepared by scalable solution-based techniques could change the way renewable energy is performed forever. Imagine buying a can of photovoltaic QD solution, and all you have to do is "paint" it on the window or wall and, with the necessary receptors to capture the energy, you have another method of clean power.

Klimov also goes on to describe the potential of QDs in lasing, "making these lasers available would benefit a range of technologies, including integrated photonic circuits, optical communications, lab-on-a-chip platforms, wearable devices, and medical diagnostics."

However, according to the paper, for further progress, inexpensive synthesizing methods that maintain laboratory-scale QD properties into market-relevant volumes, attention is needed for alternative materials that do not rely on heavy metals such as cadmium, lead, and mercury, as the toxicity of these metals poses a deterrent to future biotechnology applications.

And while Los Alamos' earlier discovery of copper-indium-selenide quantum dots removed some heavy metal toxicity issues, for the breadth of study and devices that the future may hold for QDs, the viability is still restrained due to the limitations of alternative methods of production.