maandag, januari 10, 2005

Nanotechnologists’ new plastic can see in the dark

Infrared-sensitive material five times more efficient converter of solar energy

Imagine a home with “smart” walls responsive to the environment in the room, a digital camera sensitive enough to work in the dark, or clothing with the capacity to turn the sun’s power into electrical energy. Researchers at University of Toronto have invented an infrared-sensitive material that could shortly turn these possibilities into realities.

In a paper to be published on the Nature Materials website Jan. 9, 2005, senior author Professor Ted Sargent, Nortel Networks – Canada Research Chair in Emerging Technologies at U of T’s Department of Electrical and Computer Engineering, and his team report on their achievement in tailoring matter to harvest the sun’s invisible rays.

“We made particles from semiconductor crystals which were exactly two, three or four nanometres in size. The nanoparticles were so small they remained dispersed in everyday solvents just like the particles in paint,” explains Sargent. Then, they tuned the tiny nanocrystals to catch light at very long wavelengths. The result – a sprayable infrared detector.

Professor Peter Peumans of Stanford University, who has reviewed the U of T team’s research, also acknowledges the groundbreaking nature of the work. “Our calculations show that, with further improvements in efficiency, combining infrared and visible photovoltaics could allow up to 30 per cent of the sun’s radiant energy to be harnessed, compared to six per cent in today’s best plastic solar cells.”


Professor Edward H. Sargent, Nortel Networks – Canada Research Chair in Emerging Technologies, (416) 946-5051; e-mail: