North Carolina State University use a food additive to make an efficient, semi-printed plastic solar cell. Better yet the new solar cells can be created without the use of environmentally hazardous halogen solvents and can be manufactured at room temperature, which has strong implications for large-scale commercial production.
Plastic solar cells, or organic photovoltaics, are popular because they are lightweight, flexible, transparent and inexpensive to manufacture, making them useful in multiple applications.
Unfortunately, the halogen-containing solvents used in their manufacture are an obstacle to large-scale commercialization. These solvents are key to making sure that the solar cell’s morphology, or structure, maximizes its energy efficiency; however, they are environmentally hazardous. Additionally, the use of these harsh chemicals requires a controlled environment, which adds to production costs.
Schematic illustration of semi-printed plastic solar cells in air, using food additive o-MA as solvent. Image credit: Long Ye, NC State. Click image for the largest view.
Long Ye, a postdoctoral research scholar in physics at NC State and lead author of a paper describing the work in Chemistry of Materials, wanted to find out if nontoxic solvents could provide equally efficient morphology in the manufacturing process. Ye and his colleagues developed a proof of concept semi-printed plastic solar cell that utilized o-methylanisole (o-MA) as the solvent. O-MA is a commonly used flavoring agent in foods, and is nontoxic to humans.
The researchers used soft X-ray techniques to study the morphology of their solar cell. They found that the o-MA based solar cell had similar morphology, crystalline features and device performance to those produced by halogenated solvents. The solar cell’s overall efficiency rating was around 8.4 percent.
Additionally, their cell could be produced via blade coating at ambient, or room temperature. Blade coating is a process that uses a glass blade to spread a thin layer of the photovoltaic film onto either a rigid or flexible substrate, and the process is compatible with large-scale commercial manufacturing.
Ye said, “Two of the key requirements for mass producing these solar cells are that the cells can be produced in the open air environment and that the process doesn’t pose health or environmental hazards. Hopefully this work can help pave the way for printing solar cells in ambient air.”
Other than dust contamination the blade technique should get a lot of manufacturer attention. The idea of using something as mundane as a food additive chemical is simply astonishing serendipity. Or just raw genius.
These kinds of breakouts are the most rewarding because they have attributes strongly suggesting they will scale up and find a welcoming consumer happy to get the benefits.
There is a large array of low power demanding applications that solar cells can support, and your humble writer is getting really tired of buying and replacing alkaline batteries.