Slashdot Mirror
OLEDs May Generate Electricity
NewmansDaddy writes: "According to a PCMag article, 'When the OLEDs are working as a display, you apply electricity to the materials and they emit light. It turns out, however, that if you apply light to these devices, you can get them to produce electricity; in other words, they will run backward...'"
--Mike--
A friend of mine has been working on organic solar cells for the last 4 months (MSc Project), he's hoping to reach 4% efficiency. Last time I spoke to him he was just about to put the ITO transparent contacts on, then test it with different wavelengths of light.
The possibilities of making organic solar cells have been considered almost as long as organic LEDs have been known (one of my professors was in the Cambridge group who discovered the effect) but the efficiency will probably never be near that of good polycrystaline silica.
To power my laptop I'd need half a metre square of high grade solar cell, about £500...
-Yarn - Rio Karma: Excellent
Lifetime is longer for solar cells as the electric fields are lower.
I doubt that a $3 solar cell would provide enough current to run a palmtop. Find the wattage requirements, solar cells are approx £10 per watt.
-Yarn - Rio Karma: Excellent
It was Big News earlier this year when an organic solar cell broke the 2% efficiency barrier (though it's still below 2% for sunlight.) And that's with a material specifically engineered to be an efficient solar cell.
This stuff, optimized to shine light rather than absorb it, is probably considerably less efficient. Maybe by an order of magnitude even. Combine that with the impracticality of charging your laptop even with commercial solar cells, and you've got a non-starter. Perhaps after several more generations of research this will have some use, but not now.
Douglas-Martin sunscreen's from Heinlein's stories?
IIRC, their functionality was based upon the firefly's light reaction.
"'Tis great confidence in a friend to tell him your faults, greater to tell him his." --Poor Richard's Almanac
Take a yellow or green LED and shine your handy-dandy green laser pointer ($150 @ thinkgeek, support your sponsors!) directly into the lens. You get a little over 1VDC output from the LED, but only a few milliamps of current.
I learned this trick from this page at the LED Museum. Theres a picture of this stunt there as well.
This story seems newsworthy because it's nifty new OLED properties, but it's not really news that you can get an LED to rectify some electrons out of a light source.
They are also spectrum sensitive, picking up only equal or higher energy photos. This can be verified with a microAmp meter, and a set of various high-brightness LEDs. You'll observe that a red LED will pick up red or shorter wavelengths, green only detects green and shorter wavelengths, etc.
(Red has the longest wavelength (and smallest energy per photon) of visible light, violet is the shortest wavelength, and highest energy photon.) The high energy of blue is why it's been so hard to make a blue LED for years.
Put them face to face, run the source LED at its rated current, and expect a few microAmps out of the other LED..
--Mike--
A OLED working as a light is a different animal than an OLED working as a solar cell, so, you can't have your cake and recharge it too.