Hi,
Important email. If you don't like reading big emails then please scroll down
till you see the header "IMPORTANT."
I know that an LED can capture some black body radiation and convert it to DC
electrical energy. Unfortunately, as far as I know not until recently LED's were
unable to emit or absorb any appreciable radiation near 4500 nm. A typical long
wavelength IR LED is 950 nm with 50 nm BW. Somewhere I have the figures, but
basically the amount of black body energy at room temperature between 925 nm and
975 nm is next to useless. On the other hand, the amount of black body radiation
energy between 4400 nm and 4600 nm is significant.
I have no idea how efficient these leading edge MID-IR LED's are at absorbing
such radiation, but I for one *firmly* believe it's at least worth the effort to
find out. Supposedly these 4500 nm LED's are efficient at emitting such
radiation. My experiments demonstrate normal LED's act as a good photovoltaic
cell. For example, take two similar LED's face to face. Apply ~1.5 volts on one
LED while reading the DC voltage of the other LED. Some LED's are good enough to
generate close to 1.5 volts. Now separate the LED's till you get 1 mV. Now
double the distance and if done properly you'll see the voltage will drop by
~1/2. I just received a quote from such a leading edge LED company of $108 for
one single LED! That should give you an idea just how leading edge these LED's
are. I had an idea of trying to get that LED company to perform a simple test,
rather than pay $108 + S&H to buy one LED. Here's the idea -->
IMPORTANT:
If anyone has the time, could you *please* send an email to the
http://deepredtech.com LED company requesting the following experiment, perhaps
in your own words? I would like to give them the idea that collaborated
physicists around the world are interested. And it's true, physicists would be
interested if these leading edge ultra long wavelength LED's could indeed
capture a part of the 460 Watts/m^2 blackbody radiation that's peak at ~15000 nm
at room temperature.
Now I have to admit, there's an appreciable chance this company does not have
the appropriate equipment or patience to measure this noise, as the active area
of these LED's are roughly 300 x 300 um^2. So the amount of voltage noise caused
by black body radiation could be quite small.
Here's the email I sent to [EMAIL PROTECTED] which you could use an an example.
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Hi,
Thanks for the reply! Could you possibly have someone take a quick measurement
on your LED46 since I did not see it in the datasheet? I would like to know the
rms voltage noise the LED46 generates when it's pointed at a wall of the same
temperature. So if the LED46 temperature is 300 Kelvin then the wall
temperature should also be close to 300 Kelvin. If you do not have a sensitive
rms meter capable of measuring down to 0.1 mV then even an eyeball reading of
the peek to peek voltage over say 1 minute would be great. Actually I am hoping
your LED46 generates a lot of noise. If your LED generates a lot of voltage
noise then a great deal of physicists around the world that I'm in contact with
and I would purchase the LED's.
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Regards,
Paul Lowrance
