Stanford team invents coating that cools PV cells by up to 23 F

Engineers at Stanford University in California have developed a thin, patterned silica material that can be laid on top of a traditional photovoltaic (PV) cell and cool it by up to 23 degrees Fahrenheit.

For a typical crystalline silicon cell with a 20% efficiency, 23 F of cooling would lift absolute cell efficiency by over 1%, the research team said in a press release Monday.

The fully transparent overlay allows visible sunlight to pass and reach the solar cell, while it captures and emits thermal radiation, or heat, from infrared rays. The three engineers have tested the technology on a custom-made solar absorber -- a device mimicing the properties of a PV cell without producing electricity -- covered with a micron-scale pattern designed to maximise the capability to dump heat into space.

The Stanford team believe they can scale things up, for example by using nanoprint lithography, so commercial and industrial applications of the overaly are feasible. “New techniques and machines for manufacturing these kinds of patterns will continue to advance. I'm optimistic,” said research associate Aaswath P Raman.

The transparent thermal overlays will work best in dry, clear environments.

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