| Willie.Mookie@gmail.com 2007-06-27, 8:25 pm |
| On Jun 27, 5:46 pm, Bill Ward <b...@REMOVETHISix.netcom.com> wrote:
> On Wed, 27 Jun 2007 17:25:07 +0000, Willie.Mookie wrote:
>
> <snip>
>
>
> Not quite. If green light were absorbed, leaves wouldn't appear green.
> It's mostly the red-orange (650-680nm) that's absorbed, transmitting and
> reflecting the green light.
>
> This should clarify it for you:
>
> http://kentsimmons.uwinnipeg.ca/cm1504/Image172.gif
Yep. I got that wrong. There are two reactions iirc one in the near
irc and one in the near uv - centered around green. Green is
reflected because its such a large part of the spectrum? haha..
Makes you wonder what evolution was thinking. We ought to do better
with multi-junction PV cells.
Spectralab's UTJ cells are cool, and they believe by having a variety
of doping levels on GaAs they can get 6 junction cells and over 50%
conversion efficiency from sunlight.
The problem is the cost and the limited ability to do CVD on the scale
needed compared to multi-junction silicon - when talking about CPV
panels. But high efficiency makes sense in applications that must be
installed in less sunny climates.
|