Ultra-Thin Solar Cells Can Be Bent Around A Pencil (computerworld.com.au) 51
angry tapir quotes a report from Computerworld: Scientists in South Korea have developed solar cells thin enough they can be bent around a pencil. The cells could help usher in the use of solar energy in small portable gadgets where space is at a premium. The cells are fabricated onto a flexible substrate that is just a micrometer thick -- one-half to one-quarter the thickness of other "thin" solar cells and hundreds of times thinner than conventional cells. [The team at the Gwangju Institute of Science and Technology in South Korea managed to reduce the thickness by directly attaching the cells to the substrate without the use of an adhesive. They were stamped onto the substrate and then cold welded, a process that binds two materials together through pressure, not heat. The scientists tested the cells and discovered they can almost be folded in half -- wrapped around a radius as small as 1.4 millimeters. A paper describing the work was published on Monday in Applied Physics Letters, a journal of the American Institute of Physics.]
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I don't know why they went for the pencil example. Bendable solar cells seems like something you can have large areas of on your clothes.
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And [dressing with solar cells] as long as they don't fail and set up in fire the dress...
Seriously, there is so many cases where dressing "gadgets" and "electrical thingies" near your skin is a so horrible idea...
Hence, the "pencil" example they used.
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On electric cars (Score:2)
These would go great on electric cars. They wouldn't be enough to charge the batteries for putting the car in motion, but they would be enough to power sensors, displays, entertainment systems.
And cars stay out in the sun a whole lot of time.
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Or Pittsburgh.
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Already here. Most of these run things like fans and such, but Toyota is working with one that will recharge the actual battery.
http://electrek.co/2016/06/20/toyota-prius-plug-prime-solar-panel/
“Sun power only amplifies the eco-car cred of one of the greenest vehicles. The cells charge the car even when it is parked and can boost fuel efficiency by as much as 10 percent by allowing longer electric-only driving times. The technology will only be offered in the Japan and European versions of the car
Re: Hundreds of times thinner? (Score:1)
Reading comprehension? 100 micrometers is just 1/10 millimeter.
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Know the truth, there is no pencil.
At last! (Score:4, Funny)
This is huge news for those of us that suffer from arthritis. No more struggling with those ridiculously thin pencils! Freedom at last!
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Plus, you can at last power your pencil without cumbersome batteries.
Several other questions need to be answered.... (Score:4, Insightful)
. . . like cost and durability ? If they are thin and flexible but degrade or fail easily (or are temperature sensitive, or the substrate breaks down under prolonged UV exposure, for example. . .) then it's only a nifty tech demonstrator.
Likewise, if the cost per watt is an order of magnitude higher than other, less-flexible technologies.
It's a complicated balancing act, and articles like this simply don't give much more information than a press release. Neat Tech ? Sure. Usable Tech ? Insufficient information. . .
This opens up new uses (Score:5, Interesting)
The whole point of bendability is not that people are going to start wearing solar cells on their clothing (though we could see "charging hats" for hikers), but that it becomes practical to stick cells directly onto objects that flex slightly in use, like shingles. Solar shingles could make rooftop PV a default standard for new construction.
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A far better use for the solar energy hitting a roof is a heat collector for domestic hot water. No need for expensive PV panels and batteries, just a thermostat and a small pump; energy is stored is an insulated tank until needed.
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Shingles flex? I thought they are hard clay blocks.
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That's just the tile variety. There are many other shingle materials that flex.
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It would also make it easier to apply them to curved surfaces, ie car roofs. From the article, they've tested bending them up to 1000 times, so I doubt they would hold up long on something that bends as often as clothing.
Still not suited to my application. (Score:2)
The trouble is that the solar cells only have a single direction of flexibility; as such, they cannot be applied to compound surfaces. I would like to see panels that can be applied to an aerodynamic surface, like that of a velomobile.
Still more important though, is to focus on weight, efficiency, and cost. To get about 300W I still need close to 6 square feet of panel. Further, even a lightweight panel system weighs over ten pounds.
Yes, an electric assist touring bicycle is avery special purpose; but, it
How much sunlight can it get that way? (Score:2)
Having it wrapped around a pencil certainly seems like a poor way to use a solar cell.
Efficency? (Score:2)
From the article, these are composed of thousands of GaAS micro-cells. Each cell is about 15% efficent. However, they appear to be spaced far enough apart to cover only about 1/4 of the area. That makes the array 3.75% efficent at best. Maybe future work can move them closer together.
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I don't see any mention of efficiency or spacing in any of the directly linked articles. Can you link the one you are referring to?
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http://scitation.aip.org/content/aip/journal/apl/108/25/10.1063/1.4954039
Um, we did this at the UW last year (Score:1)
And it's patented.
I've held them in my hand, at the UW CEI conference on campus.
Pressure = heat (Score:2)
"They were stamped onto the substrate and then cold welded, a process that binds two materials together through pressure, not heat."
So, heat is a localized-effect of the pressure which eventually binds the two materials.
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The article said "Pressuring (80kPa) at 170C for 20min establishes cold-welding, i.e., bonding and an electrical connection, between the bottom electrode of the microcells and the substrate electrode while melting the PR over the solar microcells, as illustrated in Fig. 1(c)." 170 C is very hot for a human, but very cold for a welding process.
http://scitation.aip.org/content/aip/journal/apl/108/25/10.1063/1.4954039