8/13/2015 Laura Schmitt, MNTL 3 min read
Written by Laura Schmitt, MNTL
Recently, quantum dots (QDs) - nano-sized semiconductor particles that produce bright, sharp, colored light - have moved from the research lab into commercial products like high-end TVs, e-readers, laptops, and even some LED lighting. However, QDs are expensive to make, so there’s a push to improve their performance and efficiency while lowering their fabrication costs.
Professor Brian T Cunningham leads the team with Ralph Nuzzo, the G. L. Clark Professor of Chemistry Professor of Materials Science and Engineering, and Andrew Alleyne, a Ralph & Catherine Fisher Professor in the department of Mechanical Science and Engineering.
With funding from the Dow Chemical Company, the research team embedded QDs in novel polymer materials that retain strong quantum efficiency. They used electrohydrodynamic jet (e-jet) printing technology to precisely print the QD-embedded polymers onto photonic crystal structures. This precision eliminates wasted QDs, which are expensive to make.
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.
“Since screens consume large amounts of energy in devices like laptops, phones, and tablets, our approach could have a huge impact on energy consumption and battery life,” she said.
“If you start with polarized light, then you double your optical efficiency,” See said. “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 1mm device (known as Robot Man) made of yellow photonic-crystal-enhanced QDs. The device is made of thousands of quantum dots, each measuring about six nanometers.
Other members of the Illinois research team include chemistry graduate student Lu Xu, who performed the polymer-QD mixing, and MechSE graduate student Erick Sutanto, who performed the e-jet printing.