Next Gen lasers and photovoltaics come closer to reality

November 14th, 2008 - 5:20 pm ICT by ANI  

Washington, Nov 14 (ANI): A team of American researchers has moved a step closer to realising much advanced technology for satellite communications and solar power generation by finding a way to slow down the cooling of electrons in nanocrystals, which can lead to more efficient photovoltaic devices.

University of Chicago researchers claim that they have successfully induced electrons in the nanocrystals of semiconductors to cool more slowly by forcing them into a smaller volume, something that was first theorized in 1990.

“Slowing down the cooling of these electronsin this case, by more than 30 timescould lead to a better infrared laser source,” said Philippe Guyot-Sionnest, Professor of Chemistry and Physics at the University of Chicago.

“This, in turn, could be used to increase the bandwidth of communication satellites, allowing for faster connections,” Guyot-Sionnest added.

He added the slow cooling of electrons in nanocrystals could lead to better, more efficient photovoltaic devices.

“This is because proposals to devise ways to extract the excess heat from these electrons as they cool are more likely to be realizedand to workdue to the fact that we now understand better what is going on with these nanocrystals,” Guyot-Sionnest said.

Slow electron cooling in nanocrystals occurs because forcing the electrons into a smaller volume leads them to oscillate between their alternate extremes within a very short period of time.

The electrons in the nanocrystals used in this experiment oscillated so fast that it became difficult for them to drag along the more sluggish vibrations of the nuclei. As a result, the energy stayed with the electrons for a longer period of time.

The slower cooling effect was difficult to induce and observe because several different mechanisms for energy loss interfered with the process.

By eliminating these other mechanisms, the researchers were able to induce and observe slower electron cooling in nanocrystals.

The study is published in Nov. 7 issue of Science. (ANI)

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