Limiting efficiency of crystalline silicon solar cells due to Coulomb-enhanced Auger recombination

Excitonic effects are known to enhance the rate of intrinsic recombination processes in crystalline silicon. New calculations for the limiting efficiency of silicon solar cells are presented here, based on a recent parameterization for the Coulomb-enhanced Auger recombination rate, which accounts for its dopant type and dopant density dependence at an arbitrary injection level. Radiative recombination has been included along with photon recycling effects modeled by three-dimensional ray tracing. A maximum cell efficiency of 29-05% has been calculated for a 90-μm-thick cell made from high resistivity silicon at 25° C. For 1 Ωcm p-type silicon, the maximum efficiency reduces from 28-6% for a 55-μm-thick cell in the absence of surface recombination, down to 27-0% for a thickness in the range 300-500 μm when surface recombination limits the open-circuit voltage to 720 mV.