Material optimum choices and parametric design strategies of a photon-enhanced solar cell hybrid system

Abstract

A novel design concept of the solar hybrid system consisting of a solar concentrator, a photon enhanced thermionic emission device (PETED), and a thermoelectric generator (TEG) is proposed. The main irreversible losses in the system are taken into account. The energy balance equations of the cathode and anode of the PETED are directly used to expound that the cathode and anode temperatures of the PETED may be changed through the different choices of the energy bandgap and electron affinity of the cathode material, the reduced electric current of the TEG, and the structure parameter of the hybrid device. Analytic expressions for the power output and efficiency of the hybrid system are derived. The maximum efficiency of the hybrid system is calculated and it is proved that the hybrid system can effectively enhance the conversion efficiency of solar energy. The optimal values of some important parameters, such as the energy bandgap and electron affinity of the PETED, the reduced electric current of the TEG, the structure parameter of the hybrid device, and the solar concentration of the hybrid system, are determined. The results obtained here will be helpful for the reasonable choice of cathode materials and the optimum design of practical hybrid devices.