Nano LED Lighting
Nano LED Lighting
Recent nano technology developments in LED lighting could lead to them becoming as bright as ordinary bulbs.
LEDs are very energy-efficient and 70% of the energy is converted to light, however just 20% of that light escapes. A high refractive index at the LED-air interface means the light is reflected straight back inside. Some LEDs are made from gallium nitride, perhaps the most optically-awkward semiconductor material of all.
Some of this extra light can be extracted by making tiny holes all over the surface of the LED. At 200 nanometres (nm) in diameter, they are 400 times narrower than a human hair but only penetrate 100nm into the LED's surface. Spaced out at 300nm apart, 160 holes would fit across a hair's width. Although a single LED chip may be around one third of a square millimetre (0.3mm by 0.3mm), that's enough space for hundreds of thousands of holes.
The process of creating these tiny holes can be expensive, however nanoengineers have found effective ways to imprint the holes into LEDs at a far greater speed, and at a much lower cost. Nanoimprint [lithography] seems to be the most suitable technology for this.
An early practical use for these LED devices is likely to be backlights within LCD TVs, replacing cold cathode tubes and helping make thin TVs even thinner.