Researchers print solar cells on paper

In the journal Advanced Materials, researchers at MIT have announced that they’ve come up with a way to create solar cells by printing photovoltaic inks on standard office printer paper or fabric, drastically reducing the cost of solar cell manufacture and opening up a wide variety of unconventional applications.

Unlike a standard ink-jet printing technique, the MIT process coats the paper using vapor-disposition at temperatures below 120 Celsius. The “printing” process takes place in a vacuum chamber where five layers of PV material are deposited in successive passes.

The result is a resilient but flexible solar cell that can can continue to generate electricity even when folded or bent. To test the cell’s durability, the MIT researchers printed a solar cell on a sheet of soda bottle (PET) plastic and then folded and unfolded it 1,000 times, with no significant loss of performance. They also ran a paper printed cell through the high tempratures inside a laser printer with similar results. In addition, the printed cells show a long shelf life as those created a year ago continue to generate electricity.

Professor of Electrical Engineering Vladimir Bulović, one of a team of MIT researchers involved in the project, said the main benefit of printed solar cells is that they can be mass produced cheaply and eliminate the cost of the expensive substrates of conventional solar cells.

Conceivably, just about any “printable” surface could be used to generate electricity. For example, the researchers said applications include everything from wall paper and window shades to billboards, building materials or the casings of consumer electronic devices, as coatings or lamination don’t reduce the materials ability to generate power.

In the past, there have been other attempts to create solar cells on paper, but the MIT breakthrough is the first to successfully use uncoated paper including tissue, tracing paper and even newsprint. On the downside, the printed cells have an efficiency of only 1 percent but that should be enough juice to charge many consumer electronic devices, Bulović said.

The paper describing the process was co-authored by MIT’s Karen Gleason, the Alexander and I. Michael Kasser Professor of Chemical Engineering and professor of Electrical Engineering Vladimir Bulović as well as graduate student Miles Barr and six other students and postdocs at MIT. The work was supported by the Eni-MIT Alliance Solar Frontiers Program and the National Science Foundation.
www.mit.edu