Parag Deotare awarded DURIP grant to probe exciton energy transport at nanoscale

The tool is expected to advance the study of exciton dynamics, which could help identify new research directions for clean energy and information technology.
Parag Deotare

Prof. Parag Deotare has been awarded a grant by the Defense University Research Instrumentation Program (DURIP) to develop a first-of-its kind tool to advance the study of exciton dynamics. Excitonic research could help define the foundation of future energy and energy conversion technologies, including LEDs and solar panels.

“One of the areas that my group explores is excitonics for next generation electronics,” Deotare said. “Excitonics can seamlessly bridge electronics and photonics to revolutionize not just energy application, but energy consumption in the form of logic processing and communication.”

An exciton is a negatively charged electron and a positively charged hole that stick together like a single particle. Excitons could be a preferable alternative to using electrons to move energy and information around in future devices. This is because excitons are charge neutral, and, unlike electrons, do not lose energy stored in parasitic capacitances as heat, which could help make devices more energy efficient.

For example, in solar cells, moving excitons out of the relatively thick layer of semiconductor that absorbs photons, or particles of light, could reduce energy loss significantly. If the excitons can be moved to a thin layer before separating the electrons and holes, the energy could be more efficiently converted to electricity.

Excitonics can seamlessly bridge electronics and photonics to revolutionize not just energy application, but energy consumption in the form of logic processing and communication.

Prof. Parag Deotare

Similarly, in LEDs, moving excitons could reduce the amount of light lost within the LED. The excitons could be moved away from the electrodes into an area designed for extracting light out of the semiconductor before allowing the electrons and holes to combine and produce a photon.

However, the current tools to study exciton dynamics are limited. An exciton is only a few nanometers in diameter, but the current tools to study how energy is transported at that scale have a resolution that is several orders of magnitude larger.

“We aim to build an ultra-high-resolution optical spectroscopy capability that can allow us to understand transport of energy at a resolution of tens of nanometers,” Deotare said. “If we understand how energy flows at that scale, we can then contemplate controlling it at that scale as well.”

Construction of the new equipment is expected to be complete within the next 18 months. It will be housed on central campus, due to the need for a space that offers very low vibration and highly specific facility temperature control.

While the tool is designed for excitonic research, the technique can be applied to the study of photonics as well as magnetics at nanoscale. Deotare hopes this will generate further avenues of collaboration with other researchers and facilities.

“My research is very multidisciplinary, and this will help us connect the theories with the materials growth to the actual devices,” Deotare said.

This project is supported by the Air Force Office of Scientific Research (AFOSR).