Researchers at the Indian Institute of Science (IISc) have created a novel hybrid of graphene and quantum dots, a breakthrough that may inspire highly efficient and controllable next-generation displays and LEDs.
Quantum dots are semiconductor nanocrystals with the potential to revolutionize diverse technologies,including photovoltaics, medical imaging and quantum computing. They can absorb UV light and produce sharp, bright colours, making them especially attractive for next-generation TVs, smartphones and LEDs. However, they are poor electrical conductors, and therefore inefficient to use in devices on their own. To improve their efficiency, researchers have tried combining them with graphene, an excellent conductor. Adding graphene would also confer the ability to tinker with the output even after fabrication, or turn the device on and off at will.
Although the combination works well for photo-detectors and sensors, it is practically useless for displays and LEDs, because quantum dots lose their ability to emit light when fused with graphene. By modifying some experimental conditions, IISc scientists have found a way to eliminate this effect and create a highly efficient and tunable hybrid material. The results, published in ACS Photonics, open up possibilities for a new generation of state-of-the-art displays and LEDs.
Quantum dots are extremely tiny particles with properties vastly superior to conventional semiconductors. When activated by UV light, they can produce visible light in different colours depending on their size. Small dots produce blue light, for example, while large ones radiate red.
They absorb light very well, but they are poor electrical conductors; quantum dot-based devices that convert light to electricity are therefore not very efficient. Graphene, on the other hand, is almost transparent to light, but it is an excellent electrical conductor. When the two are combined, graphene could, in principle, quickly pull the absorbed energy away from quantum dots, cutting down energy loss, and convert it to an electrical signal, for example. This makes it possible to create devices such as photo detectors with extremely high efficiency.
The full story is available below.
Published by Phys.org