A new class of solar-sensitive nanoparticles could make solar panels cheaper, lighter, and more flexible.

The new sun-soaking nanoparticles are called colloidal quantum dots, and researchers at the University of Toronto's Edward S. Rogers Sr. Department of Electrical & Computer Engineering think they could, aside from improving solar cell production, help developers create improved infrared lasers, gas sensors, infrared-light-emitting diodes and much more.

Colloidal quantum dots rely on two types of semiconductors to get the job done: n-type, which has a wealth of electrons, and p-type, which is has few electrons. Normally, this bifurcated setup runs amok when the dots are exposed to air, with the n-type fusing with oxygen atoms and relinquishing all its electrons.

But post-doctoral researcher Zhijun Ning and Professor Ted Sargent were able to develop a new type of colloidal quantum dot that avoids this pitfall, and refrains from binding with oxygen.

"This is a material innovation, that's the first part, and with this new material we can build new device structures," said Ning. "Iodide is almost a perfect ligand for these quantum solar cells with both high efficiency and air stability --- no one has shown that before."

Ning and Sargent's work was published this week in the journal Nature Materials. And while the breakthrough is noteworthy, more tweaking in the lab will be necessary to create cells that match and exceed the efficiency of what's currently on the market.

"The field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance, or power conversion efficiency," said Sargent. "The field has moved fast, and keeps moving fast, but we need to work toward bringing performance to commercially compelling levels."