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Zinc could replace 'rare earths' in solar cells, screens

Pete Wilton

Costly and rare indium, used in solar cells, and screens for TVs, computers, and mobile phones, could be replaced with abundant and cheap zinc, scientists at Oxford University believe.

Because of its combination of high transparency and high electrical conductivity indium tin oxide (ITO) dominates the global market for coatings for solar cells and LCD displays. The market for the material is estimated to be worth $26.8bn by 2016.

However indium, a so-called 'rare earth' metal, is relatively scarce and expensive and its supply is tightly controlled - China produces over half of the world’s indium and recently reduced its export quotas.

Peter Edwards and colleagues at Oxford University's Department of Chemistry have been investigating how to make alternative coatings from cheaper, more abundant materials. Their research has come up with new coatings based on silicon-doped zinc oxide.

The Oxford team has been working closely with Oxford University Innovation, the University's technology transfer company, to protect and commercialise its research. The team has just won the Materials Science Venture Prize, awarded by the Worshipful Company of Armourers and Brasiers, to develop manufacturing processes for the group's coatings.

Peter comments: 'Zinc is a much more abundant material than indium, and our silicon-doped zinc oxide material offers electrical conductivities around two thirds of ITO, with comparable optical transparency. In addition to solar cells, our new coating could be used with lighting displays and LCD displays used in smart phones, computers and televisions.'

Jamie Ferguson of Isis Innovation said: 'There is an exciting opportunity here for the UK – which already has strong glass and high-technology manufacturing industries – to capitalise on new technologies. Projects such as Professor Edwards' transparent conductors offer the chance to strengthen our advanced materials manufacturing base by producing highly competitive new-generation materials.'

The £25,000 prize money will be used to trial manufacturing techniques and demonstrate the use of the new thin film coatings in photovoltaic products, organic light emitting diodes and LCD displays. The work will be led by Peter Edwards and Vladimir Kuznetsov at the Department of Chemistry.