Silicon nanoparticle film can increase solar cell performance

By depositing thin films of silicon nanoârticles on silicon substrates, researchers at the University of Illinois at Urbana-Champaign have fabricated a photodetector sensitive to ultraviolet light. l
Pacing a film of silicon nanoparticles onto the silicon solar cell. by diluting particles of silicon in alcohol, covering a solar cell with it and letting the alcohol evaporate to leave the nanoparticles of silicon on the cell, the team has increased the power output by 67% in the ultraviolet range and about 10% in the visible range. According to Munir Nayfeh, a physicist at the University of Illinois, "Our results point to a significant role for charge transport across the film and rectification at the nanoparticle interface." Nayfeh also believes that this process could be added onto the existing process of cell creation at very little cost.

''Silicon is the most common semiconductor, but it has not been useful for detecting ultraviolet light until now,'' said Munir Nayfeh, a professor of physics at Illinois and a researcher at the Beckman Institute for Advanced Science and Technology. ''Ultraviolet light is usually absorbed by silicon and converted into heat, but we found a way to make silicon devices that absorb ultraviolet light and produce electrical current instead.''

Combining silicon nanoparticles with conventional silicon wafers could offer the best of both material systems, Nayfeh said. "Placing a thin layer of nanoparticles on the front of a silicon solar cell, for example, could improve the cell’s efficiency and its lifetime."

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Des physiciens d'une université de l'Illinois sont parvenus à améliorer les performances des cellules solaires de plus de 60%, et ce grâce à un simple film de silicone fluorescent appliqué sur la surface des cellules.

Munir Nayfeh, professeur de physique à l'université, explique que "sur des cellules conventionelles, les rayons ultraviolets sont renvoyés, ou filtrés par le silicium, en produisant de la chaleur potentiellement dommageable, mais pas d'électricité." Grâce à ce dispositif, la lumière ultraviolette produit bel et bien de l'énergie. Les films peuvent être appliqués sur n'importe quel type de cellules, à un coût négligeable, assurent les chercheurs.

 "Avec un film d'un nanomètre d'épaisseur, détaille Munir Nayfeh, les particules luminescentes, de couleur bleue, ont révélé un pouvoir d'optimisation de 67% sur les rayons ultraviolets, mais de moins de 3% seulement sur la lumière visible ". Les rouges, de 2,85nm d'épaisseur, dépassent quant à elles les 65% d'augmentation, et 10% en plus sur les rayons visibles.

A suivre de près-

-source:www.octillioncorp.com-

Solarparc construit un champ de 10 MW en l'Allemagne méridionale
Juillet 2007 : Après l'implentation d'une ferme solaire de 1.9 MW en avril, Solarparc AG - qui projette, construit et gère de grands parcs solaires et éolien en Allemagne - a 10 MW de projets solaires en Bavière.
Chacun des projets  utilise des modules de SolarWorld AG, qui possède 29%de Solarparc.

Alors bientôt chez nous?

BRUSSELS, Belgium, July 18, 2007. The European Union installed 2,102,535 kW of glazed solar thermal collectors last year, an increase of 47% over 2005.

The continent now has 13,453,805 kW of thermal capacity installed, according to the European Solar Thermal Industry Federation in its latest market statistics for the 27 EU member states and Switzerland. Market development last year “exceeded expectations and solar thermal heating and cooling has clearly grown out of being a niche market.”

“We are seeing growth across Europe,” says ESTIF president Gerhard Rabensteiner. “France is continuing its breathtaking growth that started in 2000; in Germany, new installations increased by 58% last year; even markets such as the UK and Ireland have finally woken up.”

Source -refocus-