July 18, 2012
This diagram shows how the photon-enhanced thermionic emission (PETE) device works. Concentrated sunlight (red arrows at the top) heat up the device’s semiconductor cathode (beige and grey upper plate) to more than 400 degrees Centigrade. Photoexcited hot electrons (blue dots) stream out of the cathode’s nanotextured underside down to the anode (white/gray surface), where they are collected as direct electrical current.
Additional solar and device heat is collected below the anode (arrow shows the cool-to-hot, blue-to-red flow) to run electricity-generating steam turbines or Stirling engines.