The US Department of Energy's National Energy Research Scientific Computing Center (NERSC) has conducted simulations showing that nanostructures half the width of a DNA strand could enhance the efficiency of LEDs. In particular, efficiency improvements were notable in the 'green gap' portion of the spectrum where efficiency in traditional LED is known to fall (Dylan Bayerl and Emmanouil Kioupakis ‘Visible-Wavelength Polarized Light Emission with Small-Diameter InN Nanowires’, to be featured in the July issue of Nano Letters).
Using NERSC’s Cray XC30 supercomputer ‘Edison’, Dylan Bayerl and Emmanouil Kioupakis in the University of Michigan’s Department of Materials Science and Engineering found that indium nitride (InN), which typically emits infrared light, will emit green light if reduced to 1nm-wide wires. Moreover, just by varying their sizes, the nanostructures could be tailored to emit different colors of light, which could lead to more natural-looking white lighting while avoiding some of the efficiency loss that existing LEDs experience at high power. “Our work suggests that indium nitride at the few-nanometre size range offers a promising approach to engineering efficient, visible light emission at tailored wavelengths,” says Kioupakis.
Picture: This simulation of a 1nm-wide InN wire shows the distribution of an electron around a positively charged hole. Strong quantum confinement in these small nanostructures enables efficient light emission at visible wavelengths. (Visualization: Burlen Loring, Lawrence Berkeley National Laboratory)