Recording power from sunshine with dyes influenced by nature

• As sunlight filters through a forest canopy, chlorophyll is hard at work recording the power of photons. Inspired by nature, scientists at NTNU are working on light-capturing dyes for solar cells to create electricity.

These aren't the sort of solar cells you'll see on the roofing system of a structure. In those silicon solar cells, light hits a couple of semiconductor layers and liberates electrons to jump between the layers. It's the motion of these electrons that creates an electric present. A dye-sensitized solar cell (DSSC) works in a comparable method, but one of the semiconductor layers is changed with a photosensitive dye that soaks up the light and launches electrons instead.

Dye-sensitized solar cells tend not to be as efficient at transforming light into electricity as their silicon counterparts. Yet they operate in low light conditions, and can be transparent and also flexible, so are much better fit to some applications. To really maximize DSSCs, a study project partially funded by the Research study Council of Norway (RCN) is trying to find means to step up their efficiency.

In a paper published in the journal Dyes and also Pigments, NTNU Ph.D. prospect David Moe Almenningen and colleagues, Odd Reidar Gautun, Bård Helge Hoff and Svein Sunde have shown that adding a certain molecule to the dyes can boost its light harvesting residential properties-- though thus far the added light comes at a price.

To harvest light a dye requirements to serve as an electron benefactor and an electron acceptor.

" When this molecule is struck by a ray of sunshine, then the electron moves from the electron-rich part to the electron-poor component," claims Almenningen.

By including something in-between the benefactor and also acceptor, chemists are able to enhance the quantity of light the cell harvests.

Almenningen's research study is investigating the enhancement of compounds featuring thiophenes, a molecule similar to benzene yet including sulfur. Thiophenes are electron-rich, so would certainly be expected to boost the light harvesting properties of the dye, he says. And also current experiments reveal that they do: the dye with one of the most thiophenes was the one that collected most light.

Not a renovation - yet.

Nevertheless, it ends up that increasing the amount of light a dye captures doesn't immediately indicate much better solar cells. In other words: you could get even more electrons, but they don't always go where you want them to.

In his experiments, Almenningen found that though it soaked up the most light, the dye with the most thiophenes really made the least reliable solar cell.

" You think you're doing something fantastic by boosting the light harvesting ability, yet then there are other reactions going on in the solar cell that are negatively impacted by these adjustments," he states.

Offers prospective advantages.

He as well as his colleagues intend to find a way to stay clear of those counterproductive impacts as well as make the most of the improved light collection. Their following action is to try modifying the dye chemically so the electrons can only go in one direction. If this is successful, it can lead to a lot more reliable solar cells.

Locating a method to increase the performance of DSSCs is just one of the barricades to extensive use. The present greatest performance is around 12%, compared with closer to 20% for a traditional business silicon solar cell.

If researchers are able to harness the light captured by dyes in these solar cells more effectively, DSSCs would potentially offer a benefit over standard crystalline solar cells when it pertains to scaling up: they are cheap to make, because they don't need a tidy area or vacuum modern technology.

One appealing avenue for DSSCs would be to integrate them right into buildings to capture the dimmer light that is usually found inside your home.

" That's where these solar cells shine," claims Almenningen. "Additionally they look quite pretty. You can tailor any type of shade you desire, they can be translucent.".

For Almenningen, however, the incentive is in figuring out exactly how changing the chemical structure impacts the efficiency of the dye: "The chemistry by itself is what's remarkable.".