What if we could outsource the manufacturing process to the very things we’re manufacturing? That’s the tantalizing promise of self-assembling systems, in which scientists use the laws of nature to get components to organize themselves into, say, a computer chip. Or in this case, a solar panel. Researchers have announced the creation of self-assembling solar cells that rely on the a principle known to everyone who’s ever made a vinaigrette salad dressing: that oil and water don’t mix.
The researchers’ efforts to made a self-assembling solar panel had been unsuccessful for years, because the components were just the wrong size. Above a certain size it’s possible to use gravity to drive self-organization; on the nanoscale it’s possible to use chemical processes, like the base pairing of DNA, to drive the assembly process. That leaves an awkward range of devices on the micrometer scale in between that aren’t heavy enough for gravity to drive assembly, but too big to be pushed around by substances like DNA [Ars Technica].
To get around this problem, the researchers designed a kind of conveyor belt. They made a solar cell substrate with regular depressions lined with low-temperature solder, which were designed to receive the individual solar cell elements. Each element had gold on one side and silicon on the other. The silicon side was painted with a hydrophobic molecule that is repelled by water, and was painted the gold side with a hydrophilic, or “water-loving,” molecule. When the elements were dumped into a vial containing oil and water, the elements neatly lined up in a row at the boundary between the two liquids. Each element had its gold side pointed towards the water.
In the study, published in the Proceedings of the National Academy of Sciences, the researchers describe how the solar cell took over the work from there. The conveyor belt process is to simply dunk the [substrate] through the boundary and draw it back slowly; the sheet of elements rides up along behind it, each one popping neatly into place as the solder attracts its gold contact. The team made a working device comprising 64,000 elements in just three minutes…. The method tackles what [experts say] is the most challenging problem – the proper alignment of thousands of parts, each thinner than a human hair [BBC News].
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Image: PNAS / Robert J. Knuesel and Heiko O. Jacobs
January 13th, 2010 at 2:50 pm
Ummm. . . To me it sounds like they already had control over the parts (one side was coated with gold) and then lost control of them (they were randomly oriented). The first rule of designing any manufacturing process is that once you have control over a part, you don’t let go. I don’t see the big deal here, but we really need more information about what the whole process looks like.
January 13th, 2010 at 4:08 pm
BCL – You are missing the point. This article focuses on one part of a process that is similar to the way that a biological cell is built. There are many parallel chemical processes that occur in a living cell, for example the production of protein molecules. Those proteins then self assemble into larger structures that make up a cell. In fact, the phrase “water loving” is often used in biology texts to describe the way cell walls are built from lipids. The next step would be to eliminate having to “control” the assembly of the individual solar cell elements, and have them self assemble. Ultimately, you’d like to pour a few raw materials into some kind of environment were finished solar arrays are the result.
May 5th, 2011 at 5:23 am
Whats up, I would like to thank you for an informative blog about a topic I have had an interest in for a long time now.I have been lurking and reading through the posts avidly so decided to express my gratitude for providing me with some very good reading material. I look forward to more, and taking a more active role in the discussions here, whilst learning too!!
July 8th, 2011 at 5:00 am
The government FIT is pretty generous and there are many sharks in the installing free solar business – so before you sign up please do make sure that you have done your sums and cost projections and got them right.
August 16th, 2011 at 7:57 am
What a beautiful work of love! Thank you for using your talents for the Glory of God. And dont get discouraged with the negative comments. Pray for them that they may connect with the Truth of how much God Loves Them.God Bless You.