Energy Harvesting Technologies

Advancing Energy-Harvesting Technologies

Nanomaterials — tiny particles of metals, oxides or organic molecules that have their own unique physical and chemical properties — are the new building blocks for constructing advanced devices that "harvest" solar energy and store it for future use in solar cells.

Scientists at the University of Notre Dame’s Center for Nano Science and Technology have engineered new organic and inorganic nanomaterials that enhance the collection and storage of light energy. A multidisciplinary research team led by Prashant Kamat, professor of chemistry and biochemistry, and senior scientist at the Notre Dame Radiation Laboratory, is mapping out these fundamental behaviors at the nanoscale — an understanding that is critical for the development of affordable, high-capacity, next-generation solar cell products.

"We are developing semiconductor nanoparticles and metal nanoparticles that can be constructed into variously shaped nanostructures — solid and hollow spheres, prisms, rods and wires — for the design of solar energy conversion devices," says Kamat. "We have one of the leading laboratories in the world for studying how electrons are transferred across boundaries of different materials, and how such processes affect the conversion of light energy in semiconductor nanostructures." This knowledge can then be used to manufacture more efficient, higher-performance solar cells.

The research team also is conducting work regarding the catalytic properties of gold and other metals at the nanoscale. For example, depositing gold nanoparticles on titanium-oxide nanostructures can boost the energy capacity of semiconductors. Gold-based molecular clusters also have been used to increase the photoconversion efficiency of solar cells. Researchers at the center are also exploring how carbon nanotubes increase the efficiency of photoelectrochemical solar cells by improving energy transport along nanostructured semiconductors — a technology that will make solar cells more powerful and longer-lasting in the future.

This energy research at the University of Notre Dame is providing the community with a better understanding of the photo-induced processes in semiconductor and metal nanostructures. These processes are crucial to the design of advanced light-harvesting devices that can deliver high-power conversion efficiency in solar cells, compared to existing technologies.

"The sun is our ultimate source of energy," says Kamat. "We believe our work with semiconductor nanomaterials and light—harvesting devices will pave the way toward efficiently and economically capturing sunlight and converting it into fuel or electricity, eliminating our need for fossil fuels, and ultimately creating a healthier environment."