Study on limiting efficiencies of a-Si:H/μc-Si:H-based single-nanowire solar cells under single and tandem junction configurations

Abstract

Detailed balance calculations are presented for a-Si:H/μc-Si:H-based single- and tandem-junction single-nanowire solar cells (S- and T-SNSCs). Our study is based on three-dimensional finite-element electromagnetic simulation and thermodynamic balanced analysis, which includes radiative and Auger recombinations simultaneously. We quantify and compare the limiting short-circuit current densities, open-circuit voltages, and light-conversion efficiencies of these highly compact photovoltaic cells, addressing especially the effect of Auger recombination on the open-circuit voltages of SNSCs. Results show that tandem design leads to much higher light-conversion capability than μc-Si:H S-SNSCs, but exhibits superior performance than a-Si:H S-SNSCs only for cells with large radii.