Creating Electric Power From Light Using Gold Nanoparticles 77
cyberfringe writes "Professor of Materials Science Dawn Bonnell and colleagues at the University of Pennsylvania have discovered a way to turn optical radiation into electrical current that could lead to self-powering molecular circuits and efficient data storage. They create surface plasmons that ride the surface of gold nanoparticles on a glass substrate. Surface plasmons were found to increase the efficiency of current production by a factor of four to 20, and with many independent parameters to optimize, enhancement factors could reach into the thousands. 'If the efficiency of the system could be scaled up without any additional, unforeseen limitations, we could conceivably manufacture a 1A, 1V sample the diameter of a human hair and an inch long,' Prof. Bonnell explained. The academic paper was published in the current issue of ACS Nano. (Abstract available for free.) The significance? This may allow the creation of nano-sized circuits that can power themselves through sunlight (or another directed light source). Delivery of power to nanodevices is one of the big challenges in the field."
I can do it too! (Score:2, Informative)
Yes
more science PR nonsense (Score:5, Informative)
I know Dawn, and I have no idea if the reporter is taking statements out of context or what...
1) This isn't photovoltaic (power generating), and nothing like photovoltaics was demonstrated. Instead, what they showed was that the resistance of a film of gold nanoparticles can be modulated by shining light on it. This isn't overstated in the actual paper, and the explanation they give is good (surface plasmons creating excited states in the polymer between the particles, in the case of red and green light). They used low power diode lasers to see the photoresponse.
2) Scaling of the system: in the paper, they tried a few different sized devices, and say they saw the same response from each of them. This is actually really bad, as you would hope to get more of this kind of response from a larger system.
3) The 1V, 1A comment: Totally crazy. They're seeing less than 1pA at 1V right now, and as they pointed out, are not seeing any scaling behavior, let alone good scaling. It's irresponsible to make (or print) this comment. If doubling the size of the device doesn't change the photoresponse, you should not assume a device 1000 times as big gives 1000 times more response.
Re:WOW! (Score:3, Informative)
Wrong.
An inch-long hair is only 90 micrometers wide. So that is 0.00354330709 square inches, so you would need something 282 times as bright as the sun.