Photon-enhanced thermionic emission solar converters with light-transparent anode: Observing significant efficiency boost

Photon-enhanced thermionic emission (PETE) converter is a promising technology that effectively combines both the photovoltaic and the photothermal effects in a synergistic manner. However, traditional PETE encounters a crucial contradiction between solar photon penetration through the cathode and recombination loss during the electron diffusion process. In this work, we have developed a novel PETE converter featuring a light-transparent anode, termed anode-incident PETE (AI-PETE), which can overcome this issue. Photo-thermo-electric models for both traditional PETE and AI-PETE converters have been developed, respectively. By employing these models, the impacts of cathode thickness, electron affinity and solar concentration ratio on these two converters were studied by using GaAs as cathode. The results indicate that, compared with the traditional configuration, this design enables the converters to maintain optimal performance under thin-film cathode conditions and at relatively high electron affinity levels, broadening the selection range of electrode materials. Specifically, when the solar concentration ratio is 500 and the cathode thickness is 0.1 μm, the power conversion efficiency is enhanced by approximately 12 percentage points. By optimizing design parameters, the efficiency of AI-PETE can exceed 25 %. This work paves the way for further development of high-efficiency AI-PETE converters in the field of concentrating solar power.