Chalmers: Nanotech to make solar cells cheaper

Research lead

Scientists at Chalmers University of Technology in Sweden have shown how to make better and cheaper solar cells by exploiting the fact that the electrons in nanoparticles of noble metals oscillate together at the same pace as the frequency of the light.

Photovoltaic solar cells are constructed of layers that absorb sunlight and convert it to electrical current. Thinner solar cells that can absorb more sunlight could yield both cheaper and more plentiful electricity. 

One way to enhance the absorption of the light harvesting material in a solar cell is to make use of nanoparticles of noble metals. Nanoparticles of noble metals have special optical properties that allow them to function as tiny antennas to catch the light, and then via their oscillations, or plasmons, to pass the energy on as electricity. Plasmons are particularly strong at certain so-called plasmon resonance frequencies, which in turn are influenced by the form, size, and surroundings of the particles.

“What we’ve done is to make use of nanotechnology to produce the particles and we’ve therefore been able to determine the properties and see how they can enhance the absorption of light of different colours,” says researcher Carl Hägglund.

The best solar cells in use today are already highly efficient, so development depends on using less material and lowering production costs.

Using solar cells made of specially designed gold nanoparticles Hägglund showed that that a layer only a few nanometres thick is required for the particles to be able to absorb light in an efficient way.