2021/01/06 by Ido Frenkel, Frenkel, Ido, Avi Niv +1
Engineering · Physics and Astronomy · #45M-01 #A.0 #Advanced Thermodynamics and Statistical Mechanics #Applied Physics (physics.app-ph) #FOS: Physical sciences #Thermal Radiation and Cooling Technologies #solar cell performance optimization
paper · pdf · doi:10.48550/arxiv.2101.01930
openalex publication_date 2021/01/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
An isolated single-junction solar cell's temperature in outer space depends only on its radiation exchange with its environment. We consider a cell with zero emissivity below its bandgap and unity above it -- an idealization so far considered to define the upper limit of photovoltaic power conversion efficiency. For this case, we show that the detailed-balance and the energy conservation laws that govern the cell's temperature and potential, cannot be mutually solved. However, the cell's temperature and potential can be determined if a finite amount of sub-bandgap emissivity is included, the exact amount of which is found by minimizing the process's entropy generation. Finally, we generalize this result to a photovoltaic system in contact with some environment, hence for terrestrial conditions. Therefore, a universal thermodynamic formulation of the photovoltaic effect emerges. Unlike former attempts to thermodynamically justify the PV effect, our formalism applies to a work producing system.