New research may enhance display & LED lighting technology

Large-area integration of quantum dots and photonic crystals produce brighter and more efficient light

11-Aug-2015 - USA

Recently, quantum dots (QDs) have moved from the research lab into commercial products. However, QDs are expensive to make so there's a push to improve their performance and efficiency, while lowering their fabrication costs.

Researchers from the University of Illinois at Urbana-Champaign have produced some promising results toward that goal, developing a new method to extract more efficient and polarized light from QDs over a large-scale area. Their method, which combines QD and photonic crystal technology, could lead to brighter and more efficient mobile phone, tablet, and computer displays, as well as enhanced LED lighting.

With funding from the Dow Chemical Company, the research team, led by Electrical & Computer Engineering (ECE) Professor Brian Cunningham, Chemistry Professor Ralph Nuzzo, and Mechanical Science & Engineering Professor Andrew Alleyne, embedded QDs in novel polymer materials that retain strong quantum efficiency. They then used electrohydrodynamic jet (e-jet) printing technology to precisely print the QD-embedded polymers onto photonic crystal structures. This precision eliminates wasted QDs.

These photonic crystals limit the direction that the QD-generated light is emitted, meaning they produce polarized light, which is more intense than normal QD light output.

According to Gloria See, an ECE graduate student and lead author of the research reported this week in Applied Physics Letters, their replica molded photonic crystals could someday lead to brighter, less expensive, and more efficient displays.

"If you start with polarized light, then you double your optical efficiency," See explained. "If you put the photonic-crystal-enhanced quantum dot into a device like a phone or computer, then the battery will last much longer because the display would only draw half as much power as conventional displays."

To demonstrate the technology, See fabricated a novel 1 mm device made of yellow photonic-crystal-enhanced QDs. The device is made of thousands of quantum dots, each measuring about six nanometers.

https://www.chemeurope.com/en/news/154063/new-research-may-enhance-display-led-lighting-technology.html