A new material in solar cell design

They’re flexible, cheap to produce and simple to make – which is why perovskites are the hottest new material in solar cell design. Engineers at the University of New South Wales have achieved a new world efficiency record in solar cell design.

Dr Anita Ho-Baillie, Senior Research Fellow at the UNSW School of Photovoltaic and Renewable Energy Engineering and Program Manager for Perovskite Solar Cell Research at the Australian Centre for Advanced Photovoltaics (ACAP), has claimed for UNSW the highest efficiency rating with the largest perovskite solar cells to date.

She said her UNSW team had achieved a 12.1 per cent efficiency rating for a 16 cm2 perovskite solar cell, the largest single perovskite photovoltaic cell certified with the highest energy conversion efficiency, independently confirmed by the international testing centre in Bozeman, Montana.

“Perovskites came out of nowhere in 2009, with an efficiency rating of 3.8 per cent, and have since grown in leaps and bounds. These results place UNSW amongst the best groups in the world producing state-of-the-art high performance perovskite solar cells. And I think we can get to 24 per cent within a year or so.”

Perovskite is the fastest-advancing solar technology to date, and is attractive because the compound is cheap to produce and simple to manufacture, and can even be sprayed onto surfaces.

Although perovskites hold much promise for cost-effective solar energy, they are currently prone to fluctuating temperatures and moisture, making them last only a few months without protection. Dr Ho-Baillie’s team is working to extend perovskites durability.

Most of the world’s commercial solar cells are made from a refined, highly purified silicon crystal and, like the most efficient commercial silicon cells (known as PERC cells and invented at UNSW), need to be baked above 800˚C in multiple high temperature steps.

Perovskites are made at low temperatures and are 200 times thinner than silicon cells.

Perovskite is a mineral of calcium titanium oxide (CaTiO3) that was discovered in the Ural Mountains in 1839 and named for Russian mineralogist Lev Perovski. Now the term ‘perovskite’ refers to any mineral with the same type of crystal structure as CaTiO3.

“We will capitalise on the advantages of perovskites and continue to tackle issues important for commercialisation, like scaling to larger areas and improving cell durability,” said ATSE Fellow, Professor Martin Green AM, Director of ACAP.

 Anita Ho-Baillie with Martin Green.

Anita Ho-Baillie with Martin Green.