Nonreciprocal Photovoltaics: The Path to Conversion of Entire Power-Beam Exergy

Abstract

Nonreciprocal photonic management can shift the absorption-emission balance in favor of absorption and enhance the conversion efficiency beyond the detailed balance Shockley - Queisser limit. Nonreciprocal photovoltaic (PV) cells can provide the conversion of the entire exergy (Helmholtz free energy) of quasi-monochromatic radiation into electric power. Recent discoveries in electromagnetics have demonstrated the ability to break Kirchhoff’s reciprocity in a variety of ways. The absorption-emission nonreciprocity may be realized via dissipationless one-way optical components as well as via the greenhouse-type electron-photon kinetics that traps the low-energy near-bandgap photons in the cell. We calculate the limiting performance of the nonreciprocal dissipationless monochromatic converter and discuss the limiting efficiency of the nonreciprocal converter based on the greenhouse effect. We also perform detailed modeling of the greenhouse effect in the GaAs PV converter and determined its PV performance for conversion of 809 nm laser radiation. In perovskite PV cells the greenhouse filter establishes a sharp absorption edge and reduces conversion losses related to the distributed PV bandgap and laser-cell matching losses.