Cheaper Plastic Solar Cells Being Developed

Today's solar cells are expensive because they are made from silicon-based, or inorganic, semiconductors.  Under development now are solar cells that will be made from organic, or carbon-based, semiconductors made from polymers.  Two different types of polymers are involved.  One is electron deficient, an organoborane polymer, and the other is electron rich, a thiophene polymer.   These new solar cells will be cheaper to create and produce.

The current project reported on by LiveScience in partnership with the National Science Foundation is a project between Diane Hinkens, Qiquan Qiao and Seth Darling,

The organoborane and thiophene polymers are chain-like molecules made from carbon, boron, sulfur and hydrogen. These polymers have alternating double bonds and are flat, characteristics necessary for electrons to travel through the backbones of the polymers and produce electricity.  When we connect the organoborane and thiophene polymers, each with opposing electronic properties, we will create a "molecular p-n junction," key to collecting and using electrons for electricity.

By synthesizing the p-n junction within the polymer molecules, the group hopes to overcome the limitations of current organic solar cells.  Additionally, they will try to incorporate molecules known to absorb different wavelengths of light into the polymer chains. By doing this, the hope is that these polymers will be able to absorb nearly the entire spectrum of visible light thereby harnessing much more of our sun's energy.

These solar cells may be inexpensive to produce because the organic polymers can be created using low-cost techniques like reel-to-reel processing, similar to the method behind newspaper printing, which results in a material that is lightweight and mechanically flexible.