MIT unveils durable solar cells printed on paper
July 13, 2011
We've been following MIT's progress on creating solar cell-coated paper since 2010, and we're excited to report the current findings of the project. What looks and feels like an ordinary sheet of paper with a fine layer of colored rectangles, is no ordinary piece of paper at all - once connected to a couple of wires, it instantly generates solar electricity. Additionally, the technology is almost as cheap and easy as printing a family snapshot from an inkjet printer. You can even fold it up, slip it in your pocket, then unfold it again for later use.
The printing process uses vapors at relatively low temperatures (less than 120C/ 248F), to transfer five fine layers of photovoltaic cells onto a piece of untreated paper, plastic or even fabric. The process takes place in a vacuum chamber where the layers are sprayed onto the same sheet of paper in successive passes, "creating a vapor-deposition process that can be carried out inexpensively on a vast commercial scale," according to MIT.
During an experiment to test the durability of the solar cells, a team of MIT students printed the cells onto a sheet of PET plastic (a thinner version than what is commonly used for soda bottles) and folded and unfolded it 1,000 times. Remarkably, there was no impact of each fold on the performance of the solar cells. In contrast, a commercially produced solar cell on the same PET plastic failed after the first fold.
"We have demonstrated quite thoroughly the robustness of this technology," says MIT Professor of Electrical Engineering Vladimir Bulović. Due to the low weight of the paper or plastic, "we think we can fabricate scalable solar cells that can reach record-high watts-per-kilogram performance," he added. "For solar cells with such properties, a number of technological applications open up."
Furthermore, by laminating the solar paper, the researchers were able to demonstrate that the system can be protected from rain and wind, and thus easily used outdoors. This achievement in itself could offer an economical solution to current solar energy systems that use glass or other expensive materials as a base.
The MIT team are currently conducting further research to improve the solar paper cell's efficiency, which currently sits at 1 percent. The team are confident that they can achieve a higher efficiency rate, although the present output is already "good enough to power a small electric gizmo," according to Bulović.
Watch the video to see the paper solar cells in action whilst being folded into a paper plane.