02 May 2012
Printable liquid solar cells developed
Scientists at the University of Southern California (USC) have found a way to cheaply produce stable liquid solar cells that can be painted or printed onto clear surfaces.
The technology relies on solar nanocrystals just 4nm in size, which, because of their small form factor, can be suspended in a liquid solution and printed like a newspaper.
While liquid nanocrystal solar cells are cheaper to fabricate than available single crystal silicon wafer solar cells, they are not nearly as efficient at converting sunlight to electricity.
This, according to Richard Brutchey, assistant professor of chemistry at the USC Dornsife College of Letters, Arts and Sciences, is due to the fact that the organic ligand molecules that are attached to the nanocrystals to keep them stable and stop them from sticking together, also insulate the crystals, reducing their ability to conduct electricity..
Brutchey and his team discovered a synthetic ligand that not only works well at stabilising nanocrystals, but actually builds tiny bridges connecting the nanocrystals to help transmit current.
With a relatively low temperature process, the researchers' method could allow for the possibility that solar cells can be printed onto plastic instead of glass without melting – resulting in a flexible solar panel that can be shaped to fit almost anywhere.
Brutchey now plans to work on nanocrystals built from materials other than cadmium, which is often restricted in commercial applications due to toxicity. "While the commercialisation of this technology is still years away, we see a clear path forward toward integrating this into the next generation of solar cell technologies," he concluded.