Spray-on solar power for the masses

Spray-on solar cells illustration

We're developing new techniques to manufacture solar power at high volume.

Experts at the Department of Physics and Astronomy and Department Chemical and Biological Engineering have developed a spray-on method of producing solar cells that can potentially combine high efficiency and low-cost.

These spray-on solar cells use material called perovskite, which is almost as effective in generating photovoltaic electricity as conventional silicon solar-cells, yet much cheaper to produce. The spray- painting method developed by our scientists reduces wastage and potentially allows for high-volume manufacturing on flat or curved surfaces.

Lead researcher Professor David Lidzey said: "This process is designed to address the challenge of large-scale manufacturing. We've found an exciting technology that takes a lab-based process to practical mass application."

Perovskite is the name given for mineral calcium titanium oxide, which was discovered in Russia’s Ural mountains by Gustav Rose in 1839. He named the mineral after 19th-century Russian mineralogist L.A. Perovski.

This process is designed to address the challenge of large-scale manufacturing. We've found an exciting technology that takes a lab-based process to practical mass application.

Professor David Lidzey, Department of Physics and Astronomy

Today, perovskite is used to describe any compound that shares the same crystalline structure as calcium titanium oxide. We’re using a synthetic perovskite to work as an absorber in solar cells.

But for perovskite to be used effectively in a solar cell, it has to be layered with other materials.

Professor Lidzey said: "Think of a solar cell like a sandwich with various layers. One of those layers - the perovskite - absorbs light, with the other layers transporting the charges generated in the perovskite and permitting them to be extracted from the device to an external circuit where they can be used to do useful work. Without the transport layers, the cell’s efficiency is reduced, so we are now developing and testing a range of new spray-on charge transport layers."

The development of spray-on perovskite solar cells has huge potential, according to Professor Lidzey. "We already know that perovskite offers the potential to combine the high performance of mature solar cell technologies with low production costs. The fact it can be spray-coated also means that manufacturers can apply it to a range of surfaces, including corrugated structures."

He said: "The best perovskite cells now have a power conversion efficiency in excess of 20 per cent. This is not so far behind that of silicon at 25 per cent - the material that dominates the world- wide solar market."

Solar energy is rapidly becoming a serious alternative to fossil fuels and the solar energy market is expanding at a pace to match. In Asia, for example, photovoltaic energy is so inexpensive it competes with oil and gas.

Professor Lidzey said: "I believe that new thin-film photovoltaic technologies are going to have an important role to play in driving the uptake of solar-energy, and that perovskite based cells are emerging as likely thin-film candidates."