Large-area integration of quantum dots promises brighter displays
08 August 2015
A team of researchers has developed a new method of extracting more efficient and polarized light from quantum dots (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 University of Illinois at Urbana-Champaign researchers 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, which are expensive to make.
These photonic crystals limit the direction that the QD-generated light is emitted, meaning they produce polarised light, which is more intense than normal QD light output.
The replica moulded photonic crystals could lead to brighter, less expensive, and more energy efficient displays.
To demonstrate the technology, graduate student Gloria See fabricated a novel 1mm device (a Robot Man) made of yellow photonic-crystal-enhanced QDs. The device is made of thousands of quantum dots, each measuring about six nanometres.
“We made a tiny device, but the process can easily be scaled up to large flexible plastic sheets,” See says. “We make one expensive ‘master’ moulding template that must be designed very precisely, but we can use the template to produce thousands of replicas very quickly and cheaply.”