Reassessment of the Limiting Efficiency for Crystalline Silicon Solar Cells

TLDR

Recent revisions to key silicon solar cell parameters, including the standard solar spectrum and intrinsic silicon properties, have prompted updated modeling. The study aims to evaluate how updated parameters affect the theoretical efficiency limit of crystalline silicon solar cells under standard test conditions. Using the narrow‑base approximation and incorporating bandgap narrowing, the authors modeled ideal silicon cells to compute efficiency limits. The updated calculations yield a maximum theoretical efficiency of 29.43 % for a 110‑µm undoped silicon cell, and systematic I‑V analyses reveal how doping and thickness influence intrinsic losses at maximum power.

Abstract

Recently, several parameters relevant for modeling crystalline silicon solar cells were improved or revised, e.g., the international standard solar spectrum or properties of silicon such as the intrinsic recombination rate and the intrinsic carrier concentration. In this study, we analyzed the influence of these improved state-of-the-art parameters on the limiting efficiency for crystalline silicon solar cells under 1-sun illumination at 25°C, by following the narrow-base approximation to model ideal solar cells. We also considered bandgap narrowing, which was not addressed so far with respect to efficiency limitation. The new calculations that are presented in this study result in a maximum theoretical efficiency of 29.43% for a 110-μm-thick solar cell made of undoped silicon. A systematic calculation of the I-V parameters as a function of the doping concentration and the cell thickness together with an analysis of the loss current at maximum power point provides further insight into the intrinsic limitations of silicon solar cells.