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Old 03-14-2019, 06:48 AM
padova padova is offline
Join Date: Jan 2015
Posts: 34
LED's efficiency exceeds 100%

The researchers, Parthiban Santhanam and coauthors from MIT, have published their study in a recent issue of Physical Review Letters.

As the researchers explain in their study, the key to achieving a power conversion efficiency above 100%, i.e., ďunity efficiency,Ē is to greatly decrease the applied voltage. According to their calculations, as the voltage is halved, the input power is decreased by a factor of 4, while the emitted light power scales linearly with voltage so that itís also only halved. In other words, an LEDís efficiency increases as its output power decreases. (The inverse of this relationship - that LED efficiency decreases as its output power increases - is one of the biggest hurdles in designing bright, efficient LED lights.)

In their experiments, the researchers reduced the LEDís input power to just 30 picowatts and measured an output of 69 picowatts of light - an efficiency of 230%. The physical mechanisms worked the same as with any LED: when excited by the applied voltage, electrons and holes have a certain probability of generating photons. The researchers didnít try to increase this probability, as some previous research has focused on, but instead took advantage of small amounts of excess heat to emit more power than consumed. This heat arises from vibrations in the deviceís atomic lattice, which occur due to entropy.
It doesn't seem as the laws of physics were broken this way.

with respect

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