Analysis of chromatic aberration effects in triple-junction solar cells using advanced distributed models

Bringing high efficiency triple-junction solar cells developed so far to a massive electricity production cost-competitiveness scenario requires the use of high concentrations. Moreover, the consideration of real operating conditions, for the design and optimization of the solar cell receiver - concentrator assembly, is compulsory. Such requirements involve the need for suitable modeling and simulation tools, in order to complement the experimental work and circumvent its well known inherent burdens and restrictions. 3D distributed models have been demonstrated in the past to be a powerful choice for the analysis of distributed phenomena in single and dual-junction solar cells, and for the design of strategies to minimize the solar cell losses when operating under high concentrations. In this contribution, we are presenting the extension of these models for the analysis of triple-junction solar cells under real operating conditions, including non-uniform irradiance and chromatic aberration. The impact of different chromatic aberration profiles, as can be found in practical concentrator optics, on the short circuit current of the triple-junction solar cell is analyzed in detail using the distributed model developed. Current spreading determines the impact of a given chromatic aberration profile on the solar cell short circuit current. The focus is put on determining its role in the connection between photocurrent profile, subcells voltage/current supplied or sink and layers sheet resistance. The advisability of modifications to the semiconductor structure for common chromatic aberration profiles, found in practical optical architectures, is discussed.