The field of nanoscale engineering, in which UT is a world leader, took a leap forward this fall when the Nobel Prize in Chemistry was awarded for work on quantum dots.
The prize was awarded jointly to Moungi G. Bawendi, Louis E. Brus and Alexei I. Ekimov for their work in discovering quantum dots, which are also known as “artificial atoms,” and in streamlining their production.
Quantum dots are miniscule semiconductor crystals with unusual optical properties. The nano-scale crystals—imagine a pinhead, and then shrink it down about a million times—have practical applications in everything from TV screens and medical imaging to solar cells and cancer treatment.
The dots are created by compressing the electrons into a miniscule space, and so limiting its ability to move. “When you stretch that environment, you change the electron’s energy,” says Rigoberto Advincula, the University of Tennessee and Oak Ridge National Laboratory (UT-ORNL) Governor’s Chair of Advanced and Nanostructured Materials.
As the energy changes, the electrons emit light according to quantum mechanical and photochemical principles. It is possible to tune the color of this light by adjusting the size of the electron’s environment. Larger dots emit colors like orange and red, while smaller dots produce greens and blues. “They emit very bright light, so they are used in display devices” such as LED TVs, says Advincula. But “they also have very important medical applications, in both diagnosis and therapy.”
Take cancer. Quantum dots allow doctors to image cancer cells more clearly. A surgeon could inject quantum dots into the site of a tumor, and the dots would brightly light up malignant areas, allowing the doctor to distinguish between the cancerous tumor and the surrounding healthy tissue more easily.
Typically, surgeons and pathologists use dyes for this task. Quantum dots, though, have several advantages over dyes. They stay in position for longer and they take more time to fade, fluorescing for hours.
Quantum dots might even allow some cancer patients to escape surgery altogether. In photodynamic therapy, a form of treatment that uses light to destroy cancerous cells, quantum dots could allow malignant cells to be targeted more effectively, without surgical interventions.
In the 1980s, Advincula says, Brus and Ekimov first created quantum dots in the lab. But it was believed to be impossible to manufacture them at scale.
In the 1990s, though, Bawendi discovered a way to manufacture them more easily. His breakthrough meant “we could now prepare quantum dots in very stable and quantifiable ways,” says Advincula. This led to “an explosion” of fundamental studies and practical applications.
Following the Nobel Committee’s announcement in October, Advincula, a specialist in nanotechnology and popular materials who has worked with quantum dots in his own research for a decade, was “very excited. I felt that the prize was overdue for them,” he says. Since then, he has been busy explaining the breakthrough to the world, and has been quoted in publications including The Washington Post and AP. He has published many high-impact papers and trained several PhD students in the field.
Advincula, a faculty member of the Department of Chemical and Biomolecular Engineering, is at the frontier of nano-scale material research himself. At UT, and ORNL’s Center for Nanophase Materials Sciences, he works on synthesizing new materials, from materials on the near-atomic scale to macromolecules, with the assistance of artificial intelligence. He and other UT researchers study how to produce new nanomaterials and macromolecules at scale, so they can be used in areas including renewable energy, clean water, national security, next-generation electronics, and drug delivery.
UT is home to cutting-edge work on the quantum scale, too. In collaboration with ORNL, and with the help of the world’s most powerful supercomputers, UT researchers are exploring and harnessing the properties of the quantum world in fields from artificial intelligence to superconductivity.
In June, the National Science Foundation awarded $18 million to UT’s Materials Research Science and Engineering Center to fund this pioneering research.
Tomas Weber (firstname.lastname@example.org)