Toronto, ON, Canada--Researchers from the University of Toronto, the King Abdullah University of Science & Technology (KAUST; Saudi Arabia), and Pennsylvania State University say they have used colloidial quantum dots to create a solar cell with record efficiency. The quantum dots act are sprayed on to flexible surfaces, enabling photovoltaics that cost less and are more durable than those based on silicon. In the work highlighted in a Nature Materials paper, the researchers demonstrate how the wrappers that encapsulate the quantum dots can be shrunk to a layer of atoms.
"We figured out how to shrink the passivating materials to the smallest imaginable size," states Ted Sargent, who led the research group and hold the Canada Research Chair in Nanotechnology at the University of Toronto. The researchers used inorganic ligands to bind the quantum dots together while using less space. The result is the same colloid characteristics but without the bulky organic molecules. A combination of close packing and charge trap elimination enabled electrons to move rapidly and smoothly through the solar cells, thus providing record efficiency.
"This finding proves the power of inorganic ligands in building practical devices," says Dmitri Talapin of The University of Chicago, who is a research leader in the field. "This new surface chemistry provides the path toward both efficient and stable quantum dot solar cells. It should also impact other electronic and optoelectronic devices that utilize colloidal nanocrystals. Advantages of the all-inorganic approach include vastly improved electronic transport, and a path to long-term stability."
As a result of the potential of this discovery, a technology licensing agreement has been signed by the University of Toronto and KAUST, which will will enable global commercialization.
SOURCE: Nature Materials: Collodial-quantum-dot photovoltaics using atomic-ligand passivation
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