Solar Cells: The Next Generation

This week I’m celebrating with my cohorts in the Advanced Technology Institute at the University of Surrey about defining the next generation of solar cells.

Solar Cells: TNG; will be inorganic in organic.

Star Trek pun intended.

We’re boldly going where no one has gone before: defining things.

Let me be absolutely clear, we’re not (just) inventing the next generation of solar cells, we’re predicting the future of solar cells. Here, I’m going to tell you why that’s important.


Traditional Solar Cell, picture credit: Scott Robinson

But first, the science part. The solar cells you will be familiar with are these huge bulky black things, bolted to rooftops all around the country. Because they cost so much, they have become a bit of a status symbol for the Guardian reader-about-town. Debate still rages as to whether or not they will ever pay themselves off (they will, by the way. Just ask your kids).

Before the first crane ever hoisted one of these things into position, however, researchers were busy looking at alternative materials. Sights were firmly set on the intriguing world of organic semiconductors. They’re cheap, they’re easy to manufacture. They’re much less bulky, and even have the potential to be flexible.

The reason that organic solar cells aren’t on rooftops now is because organic semiconductors operate in their own little realm of materials physics. There are so many avenues of research to pursue, it can be quite exciting, and a bit too easy to get lost.

In the field of organic semiconductors, you can almost take most of the physics you think you know, and throw it out the window. The key thing is, the electrons aren’t attached to things any more. When electrons suddenly get loose of their usual constraints, they become a lot less predictable. If electrons were teenage boys, in an organic semiconductor; they’d be out all night, drunk, getting into gangs, meeting girls, and having unprotected sex.

This is exciting stuff, to a researcher. The best thing about organic semiconductors (from a scientist’s perspective), is that the materials can be easily manipulated so that we can get the best out of them. One of the avenues of research involves doping them with inorganic nuggets – like quantum dots, or carbon nanotubes. It makes them work even better.

The idea of putting inorganic nuggets into organic materials is relatively new, but is gathering interest because it has so much potential. Different nuggets have different effects, and this inspires further research, which inspires further research, ad infinitum. When a researcher starts to explore the physical properties of these things, it’s very easy to get lost down some little track, some fascinating avenue that you simply must understand  – “it’s very important that I understand exactly where he was when he dropped his kebab, and how far the trails of salad extend…” Early results opened the floodgates and papers are pouring out, with every scientist keen to make his mark on the field.

It’s not hard to spot when a research topic is on the rise; any idiot can say ‘nanostructuring solar cells really hot right now’ but it takes someone with vision to say ‘this stuff is going to define the next generation.’

Having a definition for the next generation of technology sets a clear goal to all of the researchers in a field. Scientists that once wandered a disparate and lonely path suddenly have something to work to. Scientists, as well as funding bodies can look at a piece of work, or a grant proposal, and know how it fits into a very broad research area, not just a particular niche field.

Look at my old research area, organic magnetoresistance. Don’t be put off by the wordiness of the phrase, all it means is that when you put an organic semiconducting device in a magnet, it suddenly works better. It sounds pretty darn useful, doesn’t it? So why aren’t we already using this fantastic property to make our solar cells more efficient? Because the scientists have gotten lost in the details. It’s a brilliant science mystery, so the researchers trying to pin down the underlying mechanism spend a lot of time squabbling with each other about who has the correct theory, rather than who can produce the biggest effect.

I’m not saying that the details aren’t important, I’m just saying that you need to keep them in perspective. Research councils are results oriented. If your research isn’t going to have impact, it isn’t going to be funded. If someone went along to the organic magnetoresistance boys and said “Right, chaps, the next generation of organic solar cells is going to use the organic magnetoresistance effect to improve efficiency by 5%,” they might just jump up from the optical bench, realise that there is already a winning theory, and focus on turning this effect into something useful to everybody.

But this story isn’t about organic magnetoresistance. It’s about inorganics in organics. By ensuring that solar cell researchers are all working towards a common goal, here at the ATI we are trying to help make the best use of research funds. We are providing a logical timeline to the evolution of organic solar cells, with clear steps in the advancement of knowledge. We set the tone for what is expected of the research. We tell the funding bodies what’s important at the moment. We provide a route for scientists to associate their research with those important topics, and gain that funding.

Essentially, we’re lassoing a herd of scientists that could easily have gone wild. Now that we’ve all agreed on what we want to do and how we want to do it, I reckon we’ll be manufacturing efficient solar cells out of organic semiconductors on a rooftop scale within the next 10 years.

You can read more about this story in the University of Surrey Press Release, get a few more details from the ATI news page, or hear about it in their own words.


About nicolajrolfe

Dr. Nicola J. Rolfe is currently looking for her next opportunity to make a big splash in East Kent industry.
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