This news comes thanks to the work of an MIT team that demonstrates this printed document features a colored array of cell rectangles that power an LCD clock when wires are clipped to one end and a light is shined on the paper.
As MIT News puts it, “Almost as cheaply and easily as printing a photo on your inkjet, an inexpensive, simple solar cell has been created on that flimsy sheet, formed from special “inks” deposited on the paper. You can even fold it up to slip into a pocket, then unfold it and watch it generating electricity again in the sunlight.”
This is remarkable news for solar and renewable energy enthusiasts who find they continually have to accept the high costs that go hand-in-hand with solar technology.
The new technology, developed by a team of MIT researchers, was published July 8 in the journal Advanced Materials. The paper is co-authored by Karen Gleason, the Alexander and I. Michael Kasser Professor of Chemical Engineering; Professor of Electrical Engineering Vladimir Bulović; graduate student Miles Barr; and six other students and postdocs. Of importance, this work was supported by the Eni-MIT Alliance Solar Frontiers Program and the National Science Foundation.
The MIT team indicates this technique marks a huge departure from the systems that have been used so far to create most solar cells. Traditional cell technology requires exposing the substrates to potentially damaging conditions, either in the form of liquids or high temperatures.
The new printing process uses vapors, not liquids, and temperatures less than 120 degrees Celsius, say the developers, adding: “These ‘gentle’ conditions make it possible to use ordinary untreated paper, cloth or plastic as the substrate on which the solar cells can be printed.”
The process is considerably more complex than printing out a term paper, say the researchers. In order to create such an array of photovoltaic cells on the paper, five layers of material must be deposited onto the same sheet of paper in successive passes, using a mask (also made of paper) to form the patterns of cells on the surface. For do-it-yourself scientists, the process has to take place in a vacuum chamber.
According to MIT News, “The basic process is essentially the same as the one used to make the silvery lining in your bag of potato chips: a vapor-deposition process that can be carried out inexpensively on a vast commercial scale.”
The resilient solar cells still function even when folded up into a paper airplane. In their paper, the MIT researchers also describe printing a solar cell on a sheet of PET plastic (a thinner version of the material used for soda bottles) and then folding and unfolding it 1,000 times, with no significant loss of performance. By contrast, a commercially produced solar cell on the same material failed after a single folding.
“We have demonstrated quite thoroughly the robustness of this technology,” says Vladimir Bulović. In addition, because of the low weight of the paper or plastic substrate compared to conventional glass or other materials, “we think we can fabricate scalable solar cells that can reach record-high watts-per-kilogram performance. For solar cells with such properties, a number of technological applications open up.”
Indeed, a new design highway is being built for the solar industry.
This Gleason Lab video from Advanced Materials shows a paper solar cell circuit is dynamically folded and unfolded while the voltage is simultaneously measured on the meter. The paper photovoltaic is illuminated from below with simulated solar illumination.
Congratulations to all members of this MIT design team and its backers.
Photo via Patrick Gillooly