New plastic solar cell introduced

Researchers at the California Institute of Technology have developed a way to create solar panels with three valuable qualities:

1. They are very good at absorbing light
2. They are mostly made of cheap plastic and only use a very small amount of expensive semiconductors
3. They are flexible

How do they do that?

At a microscopic level, the surface of their new solar cells resemble the very rough nanowire-based solar panels. But instead of using exotic materials like indium gallium phosphide to create the cells, they use mostly plastic with a bit of silicon. These cells are then configured in arrays to build solar panels.

This structure is very good at absorbing light because there is a lot of surface area since it is not just smooth.

These solar cells have, for the first time, surpassed the conventional light-trapping limit for absorbing materials. We’ve surpassed previous optical microstructures developed to trap light. (Harry Atwater, Caltech)

The light-trapping limit of a material refers to how much sunlight it is able to absorb. The silicon-wire arrays absorb up to 96 percent of incident sunlight at a single wavelength and 85 percent of total collectible sunlight.

Part of the reason why so much light is absorbed is because each of the silicon wires (30 and 100 microns in length and only 1 micron in diameter) is a good solar cell on its own, and the light that isn’t absorbed is scattered and hits other wires. The panel is like a whole bunch of little wires joined together.

The flexibility of the panels is also important because it means that they can be manufactured using roll-to-roll processes which reduce production costs compared to non-flexible panels. These processes are in place all over the world already and could easily be converted for this type of solar panel production.

Following some additional testing, these solar cells will be available at the consumer level. Everything looks good so far and it is hoped that this cheaper material and process will be distributed within the year.