Blogs, Energy Efficiency, Solar

Colloidal Quantum Dots Capture Infrared

One of the biggest challenges to solar efficiency lies in capturing, and using, infrared light that is invisible to the eye. The wider the spectrum of light from which you can draw electricity, the more electricity you can draw.

Quantum dots may provide the answer. More specifically, Colloidal Quantum Dots (CQD).

University of Toronto physicists have published a paper describing how they used CQDs to create a cascade, which they dubbed a “Graded Recombination Layer,” that can shuttle electrons between visible and invisible layers.

The CQDs were able to create cells that in principle can reach 42% efficiency, as against the 31% maximum offering by standard, single-junction cells that only handle visible light.

The challenge now is to scale production of CQD systems using thin film techniques, according to team leader Ted Sergent. In theory this would enable the development of iPads and mobile phones that never require recharging from the wall, and the development of Building Integrated Photo Voltaic (BIPV) systems that create enough power to be viable.

Producing dots with the required characteristics, reliably and in quantity, has been the bane of many CIGS breakthrough claims over the years. That’s why First Solar remains an industry leader despite having Cadmium Telluride technology that yields only 9% efficiency.

The difference between an announcement like this and a functioning revolution is engineering.