Advances in manufacturing technology for quantum dots at Oregon State University may lead to a new generation of LED lighting that produces a more user-friendly white light, while using less toxic materials and low-cost manufacturing processes that take advantage of simple microwave heating.
Researchers say the cost, environmental, and performance improvements could produce solid state lighting systems that would help cut lighting bills by almost 50% compared to the cost of incandescent and fluorescent lighting.
A key to the advances is the use of both a 'continuous flow' chemical reactor, and microwave heating technology that is similar to microwave ovens.
The continuous flow system is said to be fast, cheap, energy efficient and cuts manufacturing costs. Plus, the researchers say, the microwave approach will translate into development of nanoparticles that are exactly the right size, shape and composition.
"There are a variety of products and technologies that quantum dots can be applied to, but for mass consumer use, possibly the most important is improved LED lighting," said Greg Herman, an associate professor and chemical engineer in the OSU College of Engineering. "We may finally be able to produce low cost, energy efficient LED lighting with the soft quality of white light that people really want."
Some of the best existing LED lighting being produced at industrial levels uses cadmium, which is highly toxic. The system currently being tested and developed at OSU is based on copper indium diselenide, a much more benign material with high energy conversion efficiency.
Quantum dots are nanoparticles that can be used to emit light, and by precisely controlling the size of the particle, the colour of the light can be controlled. They have been used for some time but can be expensive and lack optimal colour control. The manufacturing techniques being developed at OSU, which should be able to scale up to large volumes for low-cost commercial applications, will provide new ways to offer the precision needed for better colour control.
The technology may also be incorporated into lighting displays, computer screens, smart phones, televisions and other systems.
Other applications of these systems are also possible. Cell phones and portable electronic devices might use less power and last much longer on a charge. And 'Taggants', or compounds with specific infrared or visible light emissions, could be used for precise and instant identification, including control of counterfeit bank notes or products.
Pic: In this University of Chicago demonstration, a green laser excites quantum dots suspended in a fluid
Author
Tom Austin-Morgan
Source: www.newelectronics.co.uk