Question: In recent years, sliver has had the largest growth in use in nano technology, why do you use Zinc? Silver is more reactive so does Zinc oxide have special properties to do with light?

Kieren Bradley answered on 20 Mar 2014:

Absolutely, zinc oxide is known in technical jargon as a wide band-gap semiconductor; what this really means is that given the right conditions it can conduct electricity, but the wide band gap is a term which relates to what colour light the material will absorb, in the case of zinc oxide it will only absorb UV, and is transparent to visible light. The overall aim of my area of research is to make solar panels, for them you’d put a black material that absorbs all the visible light on top of the zinc oxide and light would travel through the zinc oxide and then get absorbed by the black material generating an electrical current which then flows through the zinc oxide and into your electrical circuits.

If we used silver it would reflect all the light that hits it meaning none of the light would be absorbed by the black material, also even if it could work in the way we wanted it to it would be too expensive to use. The final solar panels would need to be on millions of roofs across the country meaning we wouldn’t be able to get enough silver to make them.