Surface energy of selenium

What is it about?

Selenium has been identified as an energy critical element by the American Physical Society and the Materials Research Society because of its use in such sustainable energy technologies as thin film photovoltaic panels and quantum dot sensitized solar cells, among other applications. But the value of the surface energy of solid selenium—an important parameter in the design and performance of nanoscale devices—was unknown until recently.

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Why is it important?

The researchers set out to carefully measure this parameter under clean room conditions with controlled temperature and humidity and an uncontaminated selenium surface using the sessile drop technique. This technique involves applying a drop of different liquids with a range of liquid surface energies to a sample, and measuring the contact angle of each drop. This angle is then used in calculating the solid surface energy of the exposed selenium plane, which in this case was the (101) plane.