The worst part of my job as a materials scientist is going to conferences. They are often turgid affairs conducted in the ballrooms of hotels so identical to one another that you cant tell whether you are in Singapore or Manchester. The same speakers are there, for the most part droning on about the same thing they droned on about at the last conference. I should know, I am one of them. But occasionally, just occasionally, someone says something so radically new that it causes you sit up and actually listen. Your neighbours are no longer fiddling with their smartphones; there is the proverbial buzz in the air. This was the scene at the Materials Research Society conference in Boston last December, where a breakthrough in perovskite solar cells was announced. If perovskites mean nothing to you read on, as they may have a very big impact on your future fuel bill. If we could capture approximately 1% of the sunlight falling on to the British Isles and turn it into electricity we would meet our current energy demands. The reason no one suggests doing this rather than building wind, nuclear or conventional power stations is the cost. We currently use silicon solar cells to turn sunlight into electricity but they are expensive and require subsidies. (...) Materials scientists have been exploring other semiconductor technologies for a long while, trying to find something cheaper and better than silicon. Until recently the best bet was dye-sensitised solar cells. These have been around since the 1980s, but they have not managed to make a big impact on the energy market because, although they are cheap because they dont require billion-dollar clean-room facilities, their efficiency is generally low. This is where the new perovskite solar cells come in. There are exotic-sounding compounds, such as methylammonium trihalogen plumbates, that have a quite simple crystal structure called a perovskite. Like the dye-sensitised solar cells, these solar cells are easy and cheap to make, but they have another trick up their sleeve – they dont need a complicated diode architecture to achieve high efficiencies. Materials researchers in Oxford, led by Dr Henry Snaith, have recently shown that they can make simple perovskite solar cells with efficiencies pushing 20%. This is big news, because 20% makes them competitive with existing commercial silicon solar cells while being much cheaper to make in high volumes. They are also more suitable for incorporating into roofing materials and glass panels than silicon and so have the clear potential of being as fundamental to our city architecture as steel, concrete and asphalt. In other words, they could well be the materials that will make it possible to collect the 1% of solar energy we need as a nation, at a cost that can compete with fossil fuels. Hearing research results such as this makes you grudgingly admit conferences are worth going to, and indeed gets you wondering whether we might look back in 10 years and pinpoint this as the time the solar energy revolution really ignited. One of my industry colleagues believes so; after the talk he immediately Skyped his research group, told them to stop what they were doing and get working on perovskite solar cells. The race to commercialise them is on.
Posted on: Sun, 02 Mar 2014 11:08:15 +0000
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