Full spectrum absorption through 1eV-tuning in a p-i (MQW)-n high efficiency solar cell

Demonstration of a highly successful new solar cell design is pursued in this letter. We propose a new high efficiency solar cell design, consisting of two cells in tandem: the top cell is a triple n⁺ - n - p hetero-junction and the bottom one is a p - i - n multi-quantum well cell tuned at 1 eV through appropriate (narrow-wide gap) hetero-layers. Both PV sub-units may stand (with individual collection efficiency values at 19.7 and 22.19% respectively) alone as individual solar cells, but in this case they contribute solar photon absorption from the visible to the infrared sector of the solar spectrum. Tuning at 1 eV offers a chance for solar photon absorption at long wavelengths (especially at 1,240 nm), while small variation of quantum well widths generates optical gap variation in the neighborhood near and above of the mentioned value. Absorption edge tuning is a reasonable selection for long wavelength absorption (at 1 ev and beyond). Efficiency values above the 40% threshold seem to be feasible with improvements of this design. We conclude that for a suitable selection of well width values, most (if not all) of the long IR solar spectrum can be absorbed.