MIT unveils breakthrough printable solar cell technology
1 min read
Researchers at the Massachusetts Institute of Technology (MIT) have developed materials that make it possible to produce photovoltaic cells on paper or fabric nearly as simple as printing a document.
An inexpensive, simple solar cell has been created on a sheet formed from special 'inks' deposited on the paper. By clipping wires to the paper and shining light on it, an lcd clock can be displayed. It can be folded and, when unfolded, generates electricity once more in sunlight.
The new technique to create the solar cells, reported in a paper in Advanced Materials, represents a major departure from current systems which require exposing substrates to potentially damaging conditions, either in the form of liquids or high temperatures. The new printing process uses vapours instead of liquids and lower temperatures (less than 120°C). These conditions make it possible to use ordinary untreated paper, cloth or plastic as the substrate on which the solar cells can be printed.
In order to create an array of photovoltaic cells on the paper, five layers of material need to be deposited onto the same sheet of paper in successive passes using a mask – also made from paper – to form the patterns of cells on the surface. The process takes place in a vacuum chamber and the vapour deposition process can be carried out inexpensively and on a vast commercial scale.
In the paper, 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 1000 times, with no significant loss of performance. By contrast, a commercially produced solar cell on the same material failed after a single folding.
MIT's Professor of Electrical Engineering, Vladimir Bulovic, who worked on the project, said that 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," he noted. For example, in remote developing world locations, weight makes a big difference in how many cells could be delivered in a given load.
