Photon Enhanced Thermionic Emission for Solar Concentrator Systems

Photon Enhanced Thermionic Emission (PETE) is a newly proposed method of solar energy harvesting which combines quantum and thermal processes into a single electricity generating mechanism. The proposed PETE device can be thought of as a synthesis of a photovoltaic (PV) cell and thermionic converter, and the process is expected to overcome some of the challenges which limit either of its intellectual antecedents. Because PETE can harvest the energy of sub-bandgap photons and recover heat produced by thermalization and recombination, possible PETE conversion efficiencies exceed the theoretical limits of single junction PV cells. A PETE converter operates most efficiently at high temperatures, which would allow the waste heat of the device to be used to power a secondary thermal cycle. Principles of PETE operation and limiting efficiencies are described.