• Question: In what way are the plastic solar cells you are making better?

    Asked by willgidman1 to Jarv on 11 Mar 2012.
    • Photo: Jarvist Moore Frost

      Jarvist Moore Frost answered on 11 Mar 2012:

      I guess there’s really two questions here: “Why might plastic solar cells be better than silicon?” and “In what way do we need to improve plastic solar cells?”

      Silicon solar cells are great. We make them with similar methods to those we’ve developed for making silicon chips for electronics. As they’re essentially made out of chunks of rocks layered between metal and glass, they last for years and years. However, they have to last years and years as they take so much energy and effort to make! We make them in massive complicated factories filled with robots and vacuum ovens, vast quantities of energy and loads of different people construct them in a process that takes hundreds of steps. It’s very difficult to see how we could make enough solar cells cheaply enough in a short time frame (decades) to help seriously decarbonise our power sources.

      In the 1950s we had the plastic revolution. Instead of things being made out of expensive metal and labour-intensive wood we started synthesising (synthesising is something that a chemist says when they have cooked a new molecule out of its component parts) vast quantities of plastics, and making things by melting the plastic and squeezing or injecting it into molds. It’s so much cheaper that we can make plastic things we use just once. Obviously, this had environmental issues of its own!

      In a similar way, if we can find ways to make good enough plastic solar cells, we could very quickly produce lots and lots of them. As the methods of making them would be more like printing a newspaper (or making a screen print in Art!) than building a silicon foundry, we should be able to scale up production and share the knowledge between countries and regions more quickly.

      So if we can just get them working well enough, in just a few short years they could be produced everywhere & be making a massive difference!

      That’s the reason why I’m interested in plastic solar cells. They’re also probably be lighter weight and more flexible, which may help with applications to niche markets (like mobile phone chargers).

      So why aren’t we using them already?
      Well, current plastic solar cells do not produce enough power (they are less efficient than silicon) and they do not last long enough, the materials we make them out of degrade in sunlight, and in the presence of water. Not good for putting on a roof!

      To solve both of these problems we need new materials. Rather than rely on finding these by chance, I try to figure out ways to simulate these materials on a computer, and get the computer to try all the different possibilities so that we don’t have to.