Energy production advantage of independent subcell connection for multijunction photovoltaics

The most efficient photovoltaic devices under the AM1.5 spectrum use the design concept of dividing the solar spectrum among multiple photovoltaic subcells, or “spectrum splitting” to improve performance beyond the capabilities of single junction designs [1–3]. However, tailoring the selection of subcell band gaps to the specific design spectrum raises the possibility of increased sensitivity of efficiency to spectral variation as experienced by systems operating under natural sunlight, which in turn has the potential to compromise integrated energy production [4, 5]. While efficiency measurements under the AM1.5 spectrum provide an essential means of standardized comparison between different photovoltaic technologies, the true product of photovoltaics is cumulative energy production over days and months with conditions that can vary widely from the standard test. The photovoltaics community has an increasing interest in predicting both the standard test efficiency and the energy production behavior of different photovoltaic technologies, in particular identifying the effects of design decisions on energy production [6–8]. Here, we present an examination of the relative effect on energy production for spectrum RESEARCH ARTICLE