Speak Up Energy

Engineers at the University of California, San Diego have demonstrated that nanoparticles can increase the efficiency with which sunlight can be converted into electricity in thin-film photovoltaics, opening new prospects for solar electricity.The new solar energy device created by electrical engineers at UC San Diego could boost thin-film solar cell efficiency by increasing the number of photons (light carriers) that the cells absorb as well as the number of excited electrons it collects. The UCSD engineers are attempting to break “the theoretical limit of 31% efficiency” for conventional single junction solar cells and reach “45% sunlight-to-electricity conversion efficiencies”.

Another of the engineers’ breakthroughs is that they managed to grow nanowires directly on metal electrodes, what they say is crucial for mass use of nanowires in photovoltaic devices. They note that this is an important step toward “next-generation photovoltaics that conform to the curved surfaces like rooftops, cars or other supporting structures”. However, Clint Novotny, an engineer on the project, thinks “we are at least a decade away from this becoming a mainstream technology”. In March 2007 EU leaders signed up to a binding EU-wide target to source 20% of the bloc’s energy needs from renewables such as solar, hydro and wind power by 2020. It is widely hoped that nanotechnology will lead to novel, more powerful and cost-effective production, conversion, storage and use of energy. It is already affecting technology in batteries as it enables them to store more energy.

The initial findings of the UCSD project were published in February 2008 in Nano Letters, an American Chemical Society publication reporting on research results related to the theory and practice of nanosciences. The engineers recently received $885,000 (€573,000) from the US Department of Energy to carry out further research on the subject.

From EurActiv

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