Technology

A scientific breakthrough

The Peafowl light harvesting cell is the first direct plasmonic solar cell.

A direct plasmonic solar cell converts light into electricity using plasmonic nanoparticles as the active, photovoltaic material. Plasmonic nanoparticles can absorb up to ten times more light than other known materials. Since the Peafowl light harvesting cell is so efficient at converting the light it intercepts into electricity, it can produce electricity even when very little light is intercepted. This is the key to the ultra-high transparency of the cell.

Direct plasmonic solar cells should not be confused with plasmonic-enhanced solar cells that use plasmons to boost performance of other technologies, where the photovoltaic effect occurs in another material.

The Peafowl light harvesting cell is similar in structure to conventional organic solar cells and can therefore be inexpensively manufactured through a printing process in room temperature.

You can download a scientific paper on the technology that is co-authored by our founder Jacinto Sá here. You can also download our technical briefs below.

Peafowl Plasmonics light harvesting

There are many different kinds of solar cells on the market – silicon cells are the most well-known, but there are also organic solar cells, thin-film solar cells (e.g CIGS, CdTe), perovskite solar cells etc.

Yet, our technology differs from all other solar cell technologies in a fundamental way.

The core of our technology – the process for how light is converted to electricity – is different. In other technologies, the mechanism is based on that when a photon is absorbed by the active material, a certain amount of energy is used up to excite an electron from an electronic level to an empty level, and that electron becomes one of the electrons in the electricity current that the cell generates. For a given material, a specific amount of energy is needed to excite (“kick out”) an electron. If the photon has less energy than needed, no electron will be excited by it. If the photon has excess energy compared to what is needed, the excess will be wasted as heat.

Our light harvesting cells build on a mechanism of plasmonic electron resonance. Instead of each photon exciting one specific electron, each photon contributes to the collective excitation of electrons in the material, that produce the current. A result of this different mechanism, is that for a high-energy photon, all of the energy can be converted to electricity – nothing is wasted. There is a limit for how little energy a photon must have for conversion to occur (to produce a cell voltage), but it is much lower than what is typical for other solar cells.

The use of plasmonic electronic resonance from energy conversion enables us to have a much more efficient process since more energy can be converted from the same amount of photons. This means we need to capture much less light to produce the same amount of electricity than an organic solar cell.

*Note: There are also a type of cells called “plasmonic-enhanced solar cells”, that should not be confused with our technology. These are regular solar cells that use plasmonic nanoparticles to scatter light before it is absorbed by the active material. Our cells are direct plasmonic solar cells, where the energy conversion happens directly on the plasmonic nanoparticles.