Researchers at the Massachusetts Institute of Technology (MIT) have demonstrated a solar cell so light and thin that it can rest atop a soap bubble.

Though it may take years before the device is developed into a commercial product, the laboratory proof-of-concept shows a new approach to making solar cells that could help power the next generation of portable electronic devices.

The MIT team has achieved the thinnest and lightest complete solar cells ever made, they say. To demonstrate just how thin and lightweight the cells are, the researchers draped a working cell on top of a soap bubble, without popping the bubble.
Credits:Photo: Joel Jean and Anna Osherov

With an "all-in-one" fabrication process, the solar cell, the substrate that supports it, and a protective overcoating are created at the same time.

The substrate is made in place and never needs to be handled, cleaned, or removed from the vacuum during fabrication, thus minimizing exposure to dust or other contaminants that could degrade the cell’s performance.

In the initial proof-of-concept experiment, the MIT researchers used a common flexible polymer called parylene as both the substrate and the overcoating, and an organic material called DBP as the primary light-absorbing layer.

The entire process takes place in a vacuum chamber at room temperature and without the use of any solvents, unlike conventional solar-cell manufacturing, which requires high temperatures and harsh chemicals. Both the substrate and the solar cell are “grown” using established vapor deposition techniques.

Different materials, however, could be used for the substrate and encapsulation layers, and different types of thin-film solar cell materials, including quantum dots or perovskites, could be substituted for the organic layers used in initial tests.

The key innovation, according to researchers, is the in-line substrate manufacturing process, not the materials used.


Also: Learn about a NASA Design for Improving Solar Sails.