Wide-bandgap III-V materials for high efficiency air and underwater optical photovoltaic power transmission

Abstract

High-power optical transmission (HPOT) enables the uninterrupted transfer of power in the order of hundreds of watts over several kilometers, freeing power systems from traditional wiring constraints. Its vast versatility of applications ranges from the ocean depths to outer space. In recent years, particular emphasis has been placed on the development of efficient methods to transfer substantial amounts of power from future space-based solar power stations, which intend to generate clean energy 24/7, to Earth. Despite the immense potential of HPOT, further endeavors should be undertaken in order to enhance overall system efficiency, currently hindered below 20%. A contributing factor to this unsatisfactory performance is the state-of-the-art selection of semiconductors that constitute the receivers of the monochromatic light: the optical photovoltaic converters (OPCs). Therefore, this work aims to identify the most suitable semiconductor materials for high power (∼100 Wcm−2) and beyond transmissions in terrestrial and underwater environments. In addition, the first analytical model capable of evaluating, predicting and designing OPCs and its electrical characteristics is provided. The results indicate that III-V wide-bandgap semiconductors (≈2.5 eV), such as InGaN and InAlN, could yield significant efficiency improvements in air and, especially, in subaquatic domains with respect to existing GaAs-based devices.