Performance of photovoltaic cells in different segments of spatial-spectral distributions

In a single-bandgap solar cell, efficiency is limited by the inability to efficiently convert the broad range of energy that photons possess in the solar spectrum. One of the effective ways of enhancing the efficiency of solar cells is to split the broad solar spectrum into smaller energy ranges and to utilize each range with a photovoltaic (PV) cell of the appropriately tuned bandgap. The conventional approach to implementing this idea is to use stacks of PV cells sequentially placed in the order of increasing bandgap energy, with the highest bandgap cell at the top. Lateral spectrum splitting can avoid many of the disadvantages of this conventional approach. We demonstrate that spectrum splitting with a prism and a lens can achieve enhanced efficiency with a combination of GaAs and c-Si solar cells.