March 9, 2012 AT 4:08 pm

Ultra-efficient LED puts out more power than is pumped in


Ultra-efficient LED puts out more power than is pumped in (Wired UK).

MIT physicists have managed to build a light-emitting diode that has an electrical efficiency of more than 100 percent. You may ask, “Wouldn’t that mean it breaks the first law of thermodynamics?” The answer, happily, is no.

The LED produces 69 picowatts of light using 30 picowatts of power, giving it an efficiency of 230 percent. That means it operates above “unity efficiency” — putting it into a category normally occupied by perpetual motion machines.

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  1. The problem though is they had to heat up the air around the LED to ~100F in order to get the electrical efficiency. Hopefully they will improve this technology in the future.

  2. Not to be a wet blanket, but the article as written describes a clear violation of the second law of thermodynamics. Specifically, it’s a heat engine with no cold sink.

    I think what we have here is a case of experimental error.

  3. may want to add…

    “it doesn’t violate the conservation of energy because it appears to draw in heat energy from its surroundings instead. When it gets more than 100 percent electrically-efficient, it begins to cool down”

    Some serious tech here
    If this tech can be produced cheaply and the output can get into the 100+ mW.

  4. i’m not a specialist in this area, but the idea of converting thermal energy into photons isn’t that odd. Heat up anything up enough and you’ll get photons. Maybe they’ve figured out how to do this with relatively low temperatures.

    Maybe it doesn’t need a heat flow where as peltier does. Then again, maybe the anode is hot and cathode is cold…

  5. When will they be in stock?

  6. This works with any LED.
    You just need to set the voltage and current right, which depends on the kind of LED it is.

  7. They did not create a new LED.
    Can’t wired write their articles decent, sjees.

    The article at physorg explains it much better:

  8. Now all you need is a 100% efficient solar cell and your set. That shouldn’t be that hard right?

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