Solar Cells Will be Made Obsolete by 3D rectennas aiming at
40-to-90% efficiency:
"A new kind of nanoscale rectenna (half antenna and half rectifier) can
convert solar and infrared into electricity, plus be tuned to nearly any
other frequency as a detector.
Right now efficiency is only one percent, but professor Baratunde Cola
and colleagues at the Georgia Institute of Technology (Georgia Tech,
Atlanta) convincingly argue that they can achieve 40 percent broad
spectrum efficiency (double that of silicon and more even than multi-
junction gallium arsenide) at a one-tenth of the cost of conventional
solar cells (and with an upper limit of 90 percent efficiency for single
wavelength conversion)."
See:
http://nextbigfuture.com/2015/09/sol...ete-by-3d.html