Fundamental limits of photovoltaic conversion efficiency

Fundamental limits imposed by thermodynamic laws on photovoltaic conversion efficiency are critical for basic science and numerous applications, such as solar energy and thermal energy conversion. Recent paper [1] has demonstrated that the Carnot efficiency can be approached in the photovoltaic (PV) system with infinite number of PV cells coupled via time-asymmetric optical components. We propose and investigate a PV converter based on a single sell with time-asymmetric photon recycling. We confirm that the multi-color (multi-junction) limit of PV conversion is given by the Carnot efficiency. Operating exactly at the Carnot limit requires an infinite number of recycling processes in our design. We also establishes the single-junction limiting efficiency. The performance of this converter with the GaAs solar cell is evaluated. The same time-asymmetric photonic management may be used to enhance sensitivity of photodetectors. [1] S. Buddhiraju et al., PNAS E3609, 2018.