Hot Electrons


Hot Electrons and Photovoltaics

The term hot electrons/carriers refer to electrons that have gained very high kinetic energy after being accelerated by a strong electric field in areas of high field intensities within a semiconductor device. Hot carriers can get stuck in unwanted areas of a device and cause degradation or instability. 

Photovoltaics is the direct conversion of light into electricity at the atomic level. A typical photovoltaic system employs solar panels, each comprising a number of solar cells, which generate electrical power. However the efficiency of photovoltaic materials is compromised by their inability to capture all the energy absorbed when hot electrons form. Lead researcher Isabell Thomann of Rice University says “Hot electrons have the potential to drive very useful chemical reactions, but they decay very rapidly, and people have struggled to harness their energy.” In today’s best photovoltaic solar panels, most of the energy losses are the result of hot electrons that cool within a few trillionths of a second and release their energy as wasted heat. 

Capturing the energy of these electrons before they cool could allow solar-energy providers to significantly increase the efficiency of solar-to-electric power conversions and allow reducing the cost of solar electricity. 


Thomann and her colleagues at Rice studied light-activated nanoparticles which were captured and converted into plasmons which are waves of electrons that flow like a fluid across the metal surface of the nanoparticles. The researchers were able to convert plasmonic energy into useful heat or light. Thomann and her team created a system that uses the energy from hot electrons to split molecules of water into oxygen and hydrogen. This is important because oxygen and hydrogen are necessary for fuel cells which are devices that produce clean energy. 

If we were able to harness this method of being able to extract energy from hot electrons more efficiently, we will be able to use solar panels to their full potential. It would lead to cheaper, more accessible renewable energy and be the start of guiding the world towards 



Bibliography

“Solar water-Splitting technology developed.” ScienceDaily, Rice University, 4 Sept. 2015, www.sciencedaily.com/releases/2015/09/150904121357.htm.

Bourzac, Katherine. “Capturing "Hot" Electrons to Double Solar Power.” MIT Technology Review, MIT Technology Review, 22 Oct. 2012, www.technologyreview.com/s/419418/capturing-hot-electrons-to-double-solar-power/.

Hot Carriers; Hot Electrons, 2004, eesemi.com/hotcarriers.htm.

Bourzac, Katherine. “Solar Cells Use Nanoparticles to Capture More Sunlight.” MIT Technology Review, MIT Technology Review, 22 Oct. 2012, www.technologyreview.com/s/417555/solar-cells-use-nanoparticles-to-capture-more-sunlight/.


“Http://Www.avensonline.org/Fulltextarticles/JSUR-2332-4139-S1-0001.Html.” Journal of Surgery, 2015, pp. 01–07., doi:10.13188/2332-4139.s100001.

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