Scientists at the University of Southern California are working with very small particles of semiconductor materials to make those “liquid solar cells” – that can be painted or printed onto clear surfaces.

Richard L. Brutchey, an assistant professor of chemistry at the university’s Dornsife College of Letters, Arts and Sciences, with postdoctoral researcher David H. Webber worked with nanocrystals of the semiconductor cadmium selenide.

The cadmium selenide parts are so small they can exist as a liquid ink. Having photovoltaic properties, they can convert sunlight into electricity.

Previous work on liquid solar cells were done by attaching organic ligand molecules to the nanocrystals to keep them stable and prevent them from sticking together. The problem with this was that the molecules also insulated the crystals, thus lowering the materials’ electric conductivity.

What Mr. Brutchey and Mr. Webber did was to increase the ability of the liquid to conduct electricity.

The two discovered a synthetic ligand that stabilizes the nanocrystals while also building tiny bridges that connect the nanocrystals and increase their ability to conduct electricity.

The researchers now plan to work on nanocrystals built from materials other than cadmium, which is highly toxic, to develop a liquid solar cell using their synthetic ligand.

Liquid solar cells are cheaper to fabricate than silicon wafer solar cells. They can also be printed onto plastic and glass for flexible, lighter-weight solar panels that can be shaped and molded for applications such as building integrated PV’s.

The research was funded by the National Science Foundation and U.S.C. Dornsife.

“While the commercialization of this technology is still years away, we see a clear path forward toward integrating this into the next generation of solar cell technologies,” said Mr. Brutchey. – EcoSeed Staff