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."
WOW! (Score:3, Interesting)
TFA isn't particularly enlightning, but the news is indeed slashdot worthy but raises many questions.
While not currently aimed at solar panel technology
Why not?
their research has uncovered a way to turn optical radiation into electrical current that could lead to self-powering molecular circuits
Battery-free gizmos? It doesn't say, but it seems like the photons wouldn't have to be optical wavelengths. However, how much current does this tech produce? "we could conceivably manufacture a 1A, 1V sample the diameter of a human hair and an inch long"
WOW, that's a lot of power from a tinty surface. 1 amp at one volt is one watt; a device using this tech the size of a phone battery could run an air conditioner if there were any way to keep the thing from melting.
At the end of TFA it links the study [acs.org].
Old News (Score:2, Interesting)
Re:"Self-powering" (Score:5, Interesting)
Still, it's a cool concept...
Re:WOW! (Score:2, Interesting)
150 watts per square-inch (call it about 150 human hairs per-inch) is not in the realm of reality. That would vaporize you. The sun produces 1,353 watts per square meter on earth, discounting the atmosphere. One square meter = 1,550 square inches. So the sun produces less than 1 watt per square inch. Imagine if the sun were 150x hotter. It would not be pleasant.
TFA uses Bad Math! (Score:3, Interesting)
Consider the article's quoted claim of a 1A, 1V sample 1 inch long and the diameter of a human hair. This is plainly ridiculous.
Solar radiation intensity in near-Earth space is 1353 W/m^2 (on Earth, under all that atmosphere, it's more like 120 W/m^2). This represents the maximum possible energy input to a solar cell, of whatever design.
A human hair is about 0.001 inch in diameter, so a 1-inch piece held lengthwise covers an area of 0.001 in^2, or 6.45E-7 m^2. At the stated solar irradiance, that area will receive 873 uW of solar irradiance at MOST, in orbit, and rather less on Earth. Unless their solar cell has a 120,000% efficiency, they'll come up rather short on the 1-watt claim (1 V * 1 A = 1 W) in TFA.
I call Fuzzy Math, at least on that particular claim. The rest of their idea may well be good; let's hope the fellow who said this was misquoted, though...
Re:TFA uses Bad Math! (Score:3, Interesting)
Sun's output is nearly identical to blackbody at 5800 degrees C. In atmosphere near ground, about half the energy is in visible light spectrum, half in near-infrared. Energy falls quickly from peak in yellow-green to essentially zero at 280 nm (ultraviolet C) and shorter wavelengths. Energy slopes gently to zero from peak in yellow to nearly zero at 3000 nm (which is infrared C). Anyway, parent post neglects fact that concentration by lenses or mirrors is common practice, typical CPV setup easily works with several hundred Suns worth of energy per square unit measure.