Zinc-based transparent coating could cut cost of solar cells

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Researchers at Oxford University have won a materials science prize to develop a high-technology coating with the potential to reduce the manufacturing costs of new-generation solar photovoltaic cells.

Prof Peter Edwards, head of Inorganic Chemistry at Oxford University and Fellow of St Catherine’s College, Oxford, will use the £25,000 Materials Science Venture Prize, awarded by the Worshipful Company of Armourers and Brasiers, to develop manufacturing processes for his group’s transparent conducting oxide coatings.

Currently, Indium tin oxide (ITO) is used by over 97 per cent of the transparent conducting oxide market as it possesses a near-ideal combination of high visible-light transparency and high electrical conductivity. The total market for ITOs is estimated to be worth $26.8bn by 2016.

However, indium metal is relatively scarce, expensive and has a highly volatile price. China produces over half of the world’s indium and has recently reduced its export quotas.

The new coatings were developed as part of a programme to investigate low-cost, earth abundant materials and inexpensive deposition routes which could be used for large-area transparent conducting oxide coatings for products such as solar photovoltaic cells. These coatings are based on silicon-doped zinc oxide and provide an alternative to indium tin oxide.

In a statement, Prof Edwards said, ‘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.’

‘This new coating could seriously reduce costs for manufacturers and consumers in a very exciting and growing industry, said Prof Bill Bonfield, chairman of the Armourers & Brasiers Venture Prize judging panel.

The Oxford University researchers have worked with Dr Jamie Ferguson of Isis Innovation, the University’s technology transfer company, to protect and commercialise the coatings.

Dr Ferguson 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 Prof Edwards’ transparent conductors offer the chance to strengthen our advanced materials manufacturing base by producing highly competitive new-generation materials.’

The venture prize funding 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.

Organic LEDs are a new lighting and display technology and have the advantage of being bright, requiring less power, and being suitable for displays and flat panel monitors.