Multijunction photovoltaic device

Abstract

Photovoltaic devices (e.g., solar cells) are disclosed that include at least three radiation absorbing layers, each capable of absorbing radiation over a different wavelength range of the solar radiation spectrum. Any two of these three wavelength ranges can be partially overlapping, or alternatively they can be distinct. The layers are disposed relative to one another so as to form two junctions, each of which includes a depletion region. In some cases, the radiation absorbing layers can collectively absorb radiation over a wavelength range that spans at least about 60%, or 70%, or 80%, and preferably 90% of the solar radiation wavelength spectrum. By way of example, in some embodiments, one layer can exhibit significant absorption of solar radiation (e.g., it can absorb at least one radiation wavelength at an absorptance greater than about 90%) at wavelengths less than about 0.7 microns while another layer can exhibit significant absorption of the solar radiation at wavelengths in a range of about 0.7 microns to about 1 micron. The third layer can in turn exhibit a significant absorption of solar radiation at wavelengths greater than about 1 micron.