Concentrating photovoltaic cavity converters for extreme solar-to-electric conversion efficiencies

A concentrating photovoltaic module for providing a concentration in the range of about 500 to over 1,000 suns and a power generation capacity in a range of a few to 50 kiloWatts, said concentrating photovoltaic module comprising:

• (a) a housing having a cavity of generally optimized closed shape inside said housing, said cavity having an internal surface area As and including an opening for admitting pre-focused, direct solar radiation into said cavity, said opening having an entrance aperture area Ai that is significantly smaller than As;
• (b) a plurality of single junction solar cells within said cavity, at least some of said solar cells each having different energy bandgaps so that their spectral responses simultaneously fully span the solar spectrum;
• and
• (c) at least one wavelength filter associated with each solar cell, said at least one wavelength filter selected from the group consisting of Rugate filters and a combination of Rugate filters and stack interference filters, thereby providing selective transmission and reflection of incident solar radiation to assist in maximizing absorption of a region of said solar spectrum by solar cells having an appropriate bandgap.