Solar panels are typically heavy, which makes them expensive to install, and rigid, which limits where they can be used. In the current issue of Nature Scientific Reports, researchers describe a novel, potentially cheap way to make solar cells that are both lightweight and flexible.

The technique is meant to work with thin-film solar cells. The active part of thin-film cells—the part that gathers sunlight and generates electricity—is thin enough to be flexible, but the cells usually have to be manufactured on rigid materials such as glass to achieve the highest quality. 

Researchers led by Xiaolin Zheng, a professor of mechanical engineering at Stanford University, demonstrated a way to transfer the active materials of the solar cell from a rigid substrate onto another surface, such as a sheet of paper or plastic, the roof of a car, or the back of a smartphone. As with other solar cells, wires would then be connected to deliver power, but flexible solar cells could be used on curved surfaces, and, because they’re lightweight, they would be easier to install than conventional panels.

Although Zheng has demonstrated that the process can transfer solar cells even to cheap surfaces such as paper, in practical applications, the materials used would be limited by the need to protect the cells from the elements.