Recently, quantum dots (QDs)—nano-sized semiconductor particles that produce bright, sharp, color 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.
Researchers from the University of Illinois at Urbana-Champaign has developed a new method to extract more efficient and polarized light from quantum dots (QDs) over a large-scale area. The method combines QD and photonic crystal technology, which could lead to brighter and more efficient mobile phone, tablet, and computer displays, as well as enhanced LED lighting.
The research team have 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 polarized light, which is more intense than normal QD light output.
The research paper is published in Applied Physics Letters titled as “Polarized quantum dot emission in electrohydrodynamic jet printed photonic crystals”.
These crystals could someday lead to brighter, less expensive, and more efficient displays.
“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, they fabricated a novel 1mm device (aka Robot Man) made of yellow photonic-crystal-enhanced QDs. The device is made of thousands of quantum dots, each measuring about six nanometers.
They made a tiny device, but the process can easily be scaled up to large flexible plastic sheets. They make one expensive ‘master’ molding template that must be designed very precisely, but they can use the template to produce thousands of replicas very quickly and cheaper.
“Since screens consume large amounts of energy in devices like laptops, phones, and tablets, this approach could have a huge impact on energy consumption and battery life”.
