Limits on the open-circuit voltage and efficiency of silicon solar cells imposed by intrinsic Auger processes

Abstract

Auger recombination processes are shown to impose the most severe intrinsic bounds on the open-circuit voltage and efficiency of silicon solar cells. This applies for both heavily doped and lightly doped material. The upper bound on the open-circuit voltage of a 300- µm-thick silicon cell is 750 mV (AMO, 25°C) irrespective of substrate resistivity. This bound increases to 800 mV for a 20 µm thick cell but decreases to a maximum value of 720 mV for cells thicker than the corresponding minority carrier diffusion length. The corresponding practical bound on cell efficiency is estimated as 25 percent (AM1.5, 100 mW/cm², 28°C).