Green Design

New 3D Photonic Crystals Are Electronically and Optically Active

Researchers at the University of Illnois at Urbana-Champaign have demonstrated the first optoelectronically active 3D photonic crystal - an advance that could open new avenues for solar cells, LEDs, lasers, and more.

“We’ve discovered a way to change the three-dimensional structure of a well-established semiconductor material to enable new optical properties while maintaining its very attractive electrical properties,” said Paul Braun, a professor of materials science and engineering and of chemistry who led the research effort.

Photonic crystals can control or manipulate light in unexpected ways thanks to their unique physical structures. They can induce unusual phenomena and affect photon behavior in ways that traditional optical materials and devices can’t. However, previous attempts at making 3D photonic crystals have resulted in devices that are only optically active – that is, they can direct light – but not electronically active, so they can’t turn electricity to light or vice versa. The Illinois team’s photonic crystal has both properties.

“With our approach to fabricating photonic crystals, there’s a lot of potential to optimize electronic and optical properties simultaneously,” said Erik Nelson, a former graduate student in Braun’s lab who now is a postdoctoral researcher at Harvard University. “It gives you the opportunity to control light in ways that are very unique –to control the way it’s emitted and absorbed or how it propagates.”