Plastic sure has gotten a bad rap lately — it takes petroleum to produce it, most kinds are notoriously difficult to recycle and it can leach harmful chemicals like BPA. But that hasn’t stopped researchers from using plastic for good — many are trying to make inexpensive, organic solar cells from the substance. Now, a team of University of Washington researchers has overcome a major hurdle is making those plastic solar cells a reality by creating a way to study plastic cell structure at the nano-level. The team’s findings could significantly speed up the plastic cell development process.
Plastic solar cells are generally made by combining two materials to form a thin film, and then baking them together. As the materials bake, tiny bubbles and channels about 10,000 times smaller than the size of a human hair start to form. The structure of the bubbles and channels affects how effectively the cell will convert light into electricity. But so far, researchers haven’t been able to combine the right materials, apply the right amount of heat, or bake the thin film for the right amount of time to achieve a 10 percent efficiency threshold (the efficiency necessary to actually make these cells cheap enough and efficient enough to implement in products).
That’s where David Ginger and his team of researchers come in: They developed a way to actually observe the bubbles and channels forming, allowing scientists to determine right away whether the materials they’re working with will ever achieve a 10 percent efficiency. The system relies on an atomic force microscope that uses a needle that resembles a severely shrunken record player needle (about 10 to 20 nanometers wide–a human hair is about 60,000 nanometers wide). The needle’s tip is coated with platinum or gold, and it traces back and forth across the solar cell to record the structure of the bubbles and channels that are forming. By creating this image, researchers can learn more about the optimal structure for a plastic solar cell, and what materials and conditions it takes to form said cell.
It may still be awhile before plastic solar cells are cheap and efficient enough to actually use. But researchers assert that once the tech is optimized, the cells could be placed in purses or backpacks to charge small electronic devices like cell phones and mp3 players, and eventually could contribute a significant amount of power to the grid. Perhaps once the cells prove they can generate significant power, plastic may slightly improve its reputation as an environmental curse.
Lead Photo by Mary Levin for University of Washington