The department of materials science and engineering at Seoul National University in Korea has reportedly uncovered a way to force two excited-state intermolecular proton transfer materials into a single molecule. The technology is thought to be the basis for a white LED with the same warm glow as incandescent bulbs.
At its most basic, an LED is a semiconductor device used to convert electricity into light. LED lighting has been around since the 1960s. It was originally used as a replacement for incandescent indicators and displays, first in expensive equipment such as laboratory and test equipment, then later in appliances such as TVs, radios, telephones, calculators and watches. Just recently LEDs have begun to appear as a viable option in the residential and commercial markets for space lighting.
This application in particular has been the most exciting for consumers and suppliers alike, due to the fact that LEDs boast efficiency higher than mainstream incandescent light solutions. For example, LED bulbs are extremely energy efficient, with new products that can emit up to 140 lumens per watt, while a traditional incandescent bulb loses over 98% of its total energy through the heat it produces. Also, a standard 40 W incandescent bulb has an expected lifespan of 1000 hours, while an LED can continue to operate with reduced efficiency for more than 50 000 hours.
Traditionally, the issue with implementing mainstream LED lighting has been upfront cost, as the current manufacturing process of white LEDs is too complex, and has not matured to a point for them to be produced at low enough cost for widespread use. Also, because a typical 5 mm LED produces about 6 lumens, large commercial fixtures would require thousands of LEDs, thus creating design problems for engineers, and in the end consuming about the same power as a flourescent fixture of the same output.
Perhaps the largest hurdle to end users however, has been the low colour rendering index (CRI) of current LEDs, which is a number explaining how accurately a lighting source renders objects in true colour. Most current generation LEDs have a CRI of 70 – compared to 100 CRI for natural sunlight and certain incandescent bulbs – which is still far too low for widespread use in indoor lighting.
However, the aforementioned recent breakthrough in LED brightness may bring about wide-scale LED lighting sooner than expected. Researchers at Seoul National University developed a new and simple white LED that is the first to achieve stable white light emissions using a single molecule. In their laboratory studies, the scientists showed that the light production from an LED using the newly designed molecule was not only highly efficient but also had excellent colour stability and reproducibility, features that make it a practical white light source for numerous future applications.
The future of LEDs as a mainstream lighting solution is in many ways just beginning. Already, advances such as organic LEDs (OLEDs) have been used to produce visual displays for portable electronic devices such as mobile phones, digital cameras and MP3 players. Yet even these devices have not yet met their full potential, as they currently operate at lower efficiencies than standard LEDs and their life expectancy is still far too short (under 1000 hours) to be fully practical.
Furthermore, many of the world’s governments are steadily phasing out less efficient energy systems, which has coincided with the move towards adoption of LEDs. Over the next 10 years, China, which accounts for 70% of the world’s light bulb production, has agreed to stop the production of incandescent bulbs. Many European Union leaders have decided that the EU’s half a billion citizens will be required to adopt energy efficient lighting by the end of the decade. Similar mandates have taken place in the US and Australia as well.
As the technology and manufacturing techniques of LEDs continues to move steadily toward greater efficiency, and fluorescent and incandescent bulbs are phased out, it is projected that the market for LEDs will grow exponentially by 23% on average over the next several years. In 2009 alone, Databeans predicts that the market will reach $5,3 billion in worldwide sales, thanks to a few sweet spots in an otherwise gloomy climate, namely smartphones and LCD TVs. LEDs are one of the few semiconductor components that are expected to experience growth this year.
For more information visit www.databeans.net
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