One of his more promising efforts involves the use of plasmonic-enhanced organic photovoltaic materials. These devices don’t match traditional solar cells in terms of energy production but they are less expensive and — because they are made (or processed) in liquid form — can be applied to a greater variety of surfaces. Currently, solar power is produced with either thick polycrystalline silicon wafers or thin-film solar cells made up of inorganic materials such as amorphous silicon or cadmium telluride. Both are expensive to manufacture, Gan said.
His research involves thin-film solar cells, too, but unlike what’s on the market, he’s using organic photovoltaic materials such as polymers and small molecules that are carbon-based and less expensive.
“Compared with their inorganic counterparts, organic photovoltaics can be fabricated over large areas on rigid or flexible substrates,” Gan said, and applied to surfaces as easily as paint is on walls.
There are drawbacks to organic photovoltaic cells. They have to be thin due to their relatively poor electronic conductive properties, so without sufficient material to absorb light, it limits their optical absorption and lowers power conversion efficiency.
Their power conversion efficiency needs to be 10 percent or more to compete in the market, Gan said.
To achieve that benchmark, Gan and other researchers are incorporating metal nanoparticles and/or patterned plasmonic nanostructures into organic photovoltaic cells.
Recent material studies suggest they are succeeding, he said. Gan and his co-authors argue that, because of these breakthroughs, there should be a renewed focus on how nanomaterials and plasmonic strategies can create more efficient and affordable thin-film organic solar cells. |