Photovoltaic organic solar cells have the potential to be truly green, but often their manufacturing processes are not so green.
Petroleum- and silicon-based solar cells can be bad for the environment and nearly impossible to recycle. One possible solution to creating a truly green solar cell could be to use natural materials. On the other hand, organic solar cells, based on natural materials, are notoriously inefficient.
Researchers at Purdue University and Georgia Institute of Technology have developed a recyclable organic solar cell that is made from tree-derived cellulose. The new material, a cellulose nanocrystal, smooth enough not to interrupt solar power generation, has led to the development of an organic photovoltaic solar cell with a record 2.7% efficiency.
Additionally, because the solar cell is based on cellulose sourced from trees, it is completely recyclable if it breaks or stops working for some reason. Just put the old organic solar cell in water and, after a few minutes, the solar cell completely dissolves and can be separated into its constituent parts.
An efficiency record of 2.7% may not sound like much. When you consider that the processes that make the solar cell are green and that the cell is completely recyclable, the result is a truly sustainable solar cell. The next step will be to further develop the organic solar cell to 10% efficiency.