Nanotechnology to provide cheap solar energy

Research into new types of solar cells produced by nanotechnology was described by Professor Darren Bagnall at the World Renewable Energy Conference in Glasgow.

Professor Bagnall and his Nano Group at School of Electronics and Computer Science (ECS) have conducted extensive research into how nanotechnologies can contribute to the creation of solar cells which can be manufactured on cheap flexible substrates rather than expensive silicon wafers by using nanoscale features that trap light.

Speaking in the conference session on Photovoltaic Technology, Professor Bagnall delivered a presentation entitled: Biomimetics and plasmonics: capturing all of the light. He described how his group has investigated biomimetic optical structures, which copy the nano structures seen in nature so that they can develop solar cells which allow efficient light-trapping. One type of structure is based on an anti-reflective technique exploited by moth eyes. Others are based on metallic nanoparticles that form plasmonic structures.

'It is essential that a solar cell absorbs all of the light that is available,' he said. 'Thicker devices absorb more light and unfortunately the need to use thick layers (particularly in the case of silicon) drives up the cost and often degrades the electronic properties of devices. Effective light-trapping will allow many alternatives and systems to be considered and will allow lower quality (cheaper) material.’