Paint-on nanoparticles outperform computer chips

Filed in archive Computing & Infotech on July 17, 2006

Researchers at the University of Toronto have created a semiconductor device that outperforms today's conventional chips -- and they made it simply by painting a liquid onto a piece of glass. The finding represents the first time a so-called "wet" semiconductor device has bested traditional, more costly grown-crystal semiconductor devices, says a universitypress release:

"Traditional ways of making computer chips, fiber-optic lasers, digital camera image sensors - the building blocks of the information age - are costly in time, money, and energy," says Professor Ted Sargent, leader of the research group.
Conventional semiconductors have produced spectacular results, but they rely on growing atomically-perfect crystals at 1,000 degrees Celsius and above.

The Toronto team instead cooked up semiconductor nanoparticles particles in a flask containing extra-pure oleic acid, the main ingredient in olive oil. They then placed a drop of solution on a glass slide patterned with gold electrodes and forced the drop to spread out into a smooth, continuous semiconductor film using a process called spin-coating. They then gave their film a two-hour bath in methanol. Once the solvent evaporated, it left an 800 nanometer-thick layer of the light-sensitive nanoparticles.

At room temperature, the paint-on photodetectors were about ten times more sensitive to infrared rays than the sensors that are currently used in military night-vision and biomedical imaging.

"These are exquisitely sensitive detectors of light," says Sargent. "It's now clear that solution-processed electronics can combine outstanding performance with low cost." (photo University of Toronto)