Some cherries plucked from my latest round of googling.
I guess this will be the next trend unless the cheap plastic cells hit the market soon: Solar cells that can handle huge amounts of sunlight concentrated with reflectors at efficiencies approaching 40%.
Biggest problem here is of course is cooling.
These guys are thinking big (and would be a typical pie-in-the-sky site except for the fact that they actually have a working model:))
http://www.pyronsolar.com/US/index.htmThese guys are shooting for something smaller, eventually workable for the home market, have recently secured a large amount of funding, and are stark serious about cheap mass production and economy of scale:
http://www.energyinnovations.com/sunflower250.html...so serious that they scrapped a nice looking working design over the supplier price of a plastic molded fresnel lens... hopefully that means they will gut the price point for solar severely when the above product debuts... we'll see.
http://www.energyinnovations.com/sunpod.htmlAnd finally an older article where some folks were playing with a very interesting idea which failed to make the grade efficiency-wise (only an issue if surface area is at a premium), but might someday be useful as materials science improves. It's a glass plate coated on both sides with a film that absorbs light and floresces/reflects on the internal side. That converts a larger portion of the spectrum into light of a frequency optimized for the solar cell, and through internal reflection, concentrates light received on the large flat area to the edges of the plate, where it can be collected by small size cells. That helps solve the cooling problem, as the cells don't get hit with light that they can only turn into heat. Plus, it processes diffuse light very well -- which might make a heliostat unneccessary. I don't understand the theory but they also claim the concentrators can limit the light level to within the tolerance of the cell without any control circuits or whatnot. No working model, just theory and simulation in this case.
http://www.solgel.com/articles/Sept01/ren_solar.htm