Schottky junction-based thermophotovoltaic-thermionic devices

A conceptual model of a Schottky junction (SJ)-based thermophotovoltaic-thermionic device (SJTTD) that can simultaneously convert thermally emitted electrons and photons into electricity is proposed, where the thermionic cell (TIC) is composed of a tungsten-based cathode and anode, and the thermophotovoltaic cell (TPVC) is made of a thermal emitter and an SJ. The thermal emitter simultaneously acts as the cathode of the TIC and the anode/p-type silicon interface forms the SJ. The impacts of space charge effect on the TIC and radiative recombination on the TPVC are taken into account. According to the theory of statistical physics, analytical expressions for the total power output density and energy conversion efficiency of the SJTTD are derived. The maximum power output density and efficiency are calculated numerically by optimizing the key parameters of the two subsystems. Further, the parametric optimum criteria are provided. The optimally operating states of the ideal and non-ideal SJTTDs are compared. The results show that selecting cathode materials with high emissivity can significantly enhance the performance. The proposed model may be helpful for developing high-efficiency hybrid electron devices.