Efficiency limits of Si/SiO2 quantum well solar cells from first-principles calculations

Abstract

In order to investigate the applicability of new photovoltaic absorber materials, we show how to use first-principles calculations combined with device simulations to determine the efficiency limits of solar cells made from SiO2/Si superlattices and from coaxial ZnO/ZnS nanowires. Efficiency limits are calculated for ideal systems according to the Shockley–Queisser theory but also for more realistic devices with finite mobilities, nonradiative lifetimes, and absorption coefficients. Thereby, we identify the critical values for mobility and lifetime that are required for efficient single junction as well as tandem solar cells.