With oil and gas production in gradual decline, only the sun can help bridge the energy gap that fossil fuels will leave behind, suggests Dublin physicist, Prof Shay Curran
The Trinity graduate who is now an associate professor at the University of Houston understands the great potential of the sun given his work in nanotechnology and the development of new types of solar cells.
Tonight Prof Shay Curran delivers a free public lecture entitled, The Role of Nanotechnology in Solar Energy Generation at Dublin Institute of Technology.
The sun pours more energy onto the Earth's surface in an hour than the planet uses in a year, so only the sun can deliver a way out of a future energy crisis, he argues.
"I am going to discuss what to do about energy," he explains prior to the talk. Fossil fuel costs are rising and we are heavily dependent on imports. Oil and gas are also a key source of climate changing carbon.
"At the moment there is no solar initiative," says Curran, but he believes one should be launched. Until this happens he is applying 15 years of experience with nanomaterials in an effort to build a new type of solar panel that is both cheap and flexible.
Existing solar panels are based on inorganic chemistry. They are made of rigid silicon and while effective, giving conversion efficiencies of between 12 and 20 per cent they are very expensive.
He is going "organic" in a chemistry sense, producing thin film solar cells combining modified fullerenes suspended in a polymer layer. "We are sticking to the organics because they are much simpler, cheaper and flexible substances," he says.
When Curran says flexible he means flexible. He envisages uses such as coatings on tent fabrics where the tent itself provides the electricity, or fabric-like sheets that can be thrown over a roof top to generate electricity for the home. Imagine a beach towel that also powers an MP3 player or a radio powered by the sun.
Organic cells deliver far less electricity - so far. You would need two or 2.5 times as much surface area than with an inorganic photovoltaic cell and organics currently operate at just over five per cent efficiency.
"At the end of 2005 we achieved the highest efficiency for organic photovoltaics in the world, at just over five per cent," he states. "If we manage to get to 10 per cent efficiency we will change the world of photovoltaics."
The materials are straightforward enough, he suggests. "We take a polymer, dissolve it in a solvent, add fullerenes and spin coat it to produce a thin film. It is that simple," he says.
There is a technical reason for having a thin device, as thick polymer composites will not deliver an electron flow. The moving electrons get bogged down in the polymer.
"The issue you have is mobility. You have to have very thin devices. We work with 100 nanometre thick devices," he says. That is a coating just 100 millionths of a metre thick, really too small a size to comprehend.
Even smaller are the fullerenes embedded in the polymer that support the electron flow. A fullerene is a molecule containing just 60 atoms of carbon. Named after the architect Richard Buckminster Fuller, round fullerenes are also know as "buckyballs" and tubular designs are called buckytubes.
Curran uses buckyballs that have an attachment, a "functional group" that both helps get an even distribution of fullerenes through the polymer but also makes them less reactive. "In a plastic if you stick on an attachment on the buckyball you get a great solar cell. They are very happy to generate electrons for you," he says.
"The theoretical maximum efficiency for the substances we are using is 15 per cent," he adds so there is plenty of potential for improvement.
Efficiency levels will rise as the research progresses, he believes. "We will do this by introducing new materials and by changing the architecture of the photovoltaics, say producing tubes rather than flat panels."
He is also looking at mixed photovoltaics, combining lower efficiency substances that respond to specific wavelengths. These responses add together to produce a higher total efficiency. "By being a little bit more sophisticated with the devices you can get a higher efficiency."
Prof Curran's lecture takes place today at 4pm. It is free but space is limited. Book a place by phoning Sinead Hennessy at 01-4023022 or by e-mail on sinead.hennessy@dit.ie