Nano-Sized Gold Particles to Convert Light into Electricity

So far photovoltaic solar cells have been the major players involved in the conversion of light into electricity. However a rather sophisticated invention by material scientists at University of Pennsylvania, USA may now shift this focus towards a nano-sized molecular circuit of gold!

What are we talking about here?

A system comprising of an array of nano-sized molecules of gold that respond to electromagnetic waves of light by creating surface plasmons that induce and project an electrical current across the gold molecules.

Never heard of Plasmons before?

No worries. Let us clarify the term for you.

Plasmons are density waves of electrons, created when light hits the surface of a metal under precise circumstances. A plasmon is therefore a collective excitation of the electronic ‘fluid’ in a piece of conducting material, which can be likened to the ripples on the surface of a pond which are a collective mode of the water molecules of the liquid. Plasmons can theoretically encode a lot of information, more than what’s possible for conventional electronics.

So how was this system put together?

The researchers arranged an array of light sensitive, gold nanoparticles, and linked them on a glass substrate. Then the space between the nano particles was minimized to an optimal distance. Optical radiation was then used to excite conductive electrons, called plasmons, to ride the surface of the gold nanoparticles and focus light to the junction where the molecules are connected.

The plasmon effect increasesthe efficiency of current production in the molecule by a factor of 400 to 2000 percent, which can then be transported through the network to the outside world.

The result?

A high efficiency, energy harvesting nano-sized circuit that can power itself, potentially through sunlight!

It can also be used for computer data storage where data can be stored according to the wavelengths of light.

Finally the developers believe that if the efficiency of the system could be scaled up without any additional limitations, they could quite possibly manufacture a one-amp, one-volt sample that is only an inch long and has the diameter of a human hair!

News and Image via: University of Pennsylvania (Link 1) (Link 2)

Spectrum Image Credit: NASA