Liquid Solar Cells
The liquid solar cells applied to a glass slide. (Credit: Dietmar Quistorf/USC)
A new development in liquid nanocrystal solar cells, discovered by scientists at USC, potentially could provide cheaper, stable solar cells. Previously these liquid nanocrystal solar cells, which are cheaper to fabricate but not nearly as efficient at converting sunlight into energy as silicon wafer solar cells, were developed by attaching organic ligand molecules to the nanocrystals to keep them stable and prevent them from sticking together. However, the molecules also insulated the crystals making them extremely inefficient at conducting electricity.
The scientists at USC discovered a new surface coating, made from a synthetic ligand, that not only works to stabilize the nanocrystals, but also builds tiny bridges that actually connect the nanocrystals to help transmit the current. This has solved one of the key problems of liquid solar cells: how to create a stable liquid that also conducts electricity. The solar nanocrystals are so small that you could fit 250,000,000,000 on the head of a pin and can be floated in a liquid solution so, “like you can print a newspaper, you can print solar cells,” according to Richard L. Brutchey, one of the developers and assistant professors of chemistry at the USC Dornsife College of Letters, Arts and Sciences.
The method also uses a relatively low-temperature process, creating the possibility of printing the solar cells onto plastic instead of glass without melting. This results in a flexible solar panel that can be shaped to fit anywhere. Commercialization of this product is still a ways off but there is a clear path towards integrating the technology in the next generation of solar cells.
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