The next generation of solar cells may be flexible, transparent and more energy efficient, says Silvija Gradečak, the Thomas Lord Associate Professor in Materials Science and Engineering, whose Laboratory for Nanophotonics and Electronics at MIT is working to develop semiconducting nanowires for solar cells, as well as for light emitting diodes (LEDs) that can replace inefficient light bulbs.
“Nanostructured materials would enable development of solar cells that are flexible, can be produced in large scale using roll to roll processing, and are potentially transparent, meaning that we could use them on surfaces like windows, cars, etc. The new class of nanostructured solar cells is not necessarily competing with the existing silicon technology, but it would enable development of devices that do not exist on the market right now. The goal is to develop solar cells that absorb as much solar light as possible and at the same time, we are developing LEDs that are producing light in as efficient a manner as poassible,” Gradečak says.
Gradečak’s lab focuses on three pillars: growth, characterization and devices. “Nanostructured materials are unique because of their dimensions, and because of that nano dimensionality, they have unique properties that are very distinct from their bulk counterparts. The main challenge remains how to modify their structure, the chemistry, the doping on the atomic scale for a desired application. The main research goals in my group are to develop the growth techniques and methods that will allow us to modify the structure and the chemistry of nanomaterials on the atomic scale. To accomplish that goal, we combine different synthesis methods, characterization and device fabrication,” she says.
“Our goal is to understand the complexity of the nanowire synthesis that will enable us to modify the materials in a predefined way,” Gradečak says. “Nanowires themselves can act both as the absorption medium, meaning that they can absorb the light, and at the same time, they can transport the charges to the corresponding electrodes because of their one dimensionality.”