Engineers at the University of New South Wales in Sydney are claiming to have broken the world efficiency record for perovskite solar cells.

The 12.1% efficiency rating was for a 16cm2 perovskite solar cell, the largest single perovskite photovoltaic cell certified with the highest energy conversion efficiency, and was independently confirmed by the international testing centre Newport Corp, in Bozeman, Montana.

Speaking at the Asia-Pacific Solar Research Conference in Canberra, Anita Ho-Baillie, a senior research fellow at the Australian Centre for Advanced Photovoltaics (ACAP), said the cell created by her team at UNSW is at least 10 times bigger than the current certified high-efficiency perovskite solar cells on record.

Her team has also achieved an 18% efficiency rating on a 1.2cm2 single perovskite cell, and an 11.5% for a 16cm2 four-cell perovskite mini-module, both independently certified by Newport.

Perovskite is a structured compound, where a hybrid organic-inorganic lead or tin halide-based material acts as the light-harvesting active layer. They are the fastest-advancing solar technology to date, and are attractive because the compound is cheap to produce and simple to manufacture, and can even be sprayed onto surfaces.

“The versatility of solution deposition of perovskite makes it possible to spray-coat, print or paint on solar cells,” said Ho-Baillie. “The diversity of chemical compositions also allows cells be transparent, or made of different colours. Imagine being able to cover every surface of buildings, devices and cars with solar cells.”

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 multi high-temperature nature steps. Perovskites, on the other hand, are made at low temperatures and 200 times thinner than silicon cells.

But 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. Along with every other team in the world, Ho-Baillie’s is trying to extend its durability.

Nevertheless, there are many existing applications where even disposable low-cost, high-efficiency solar cells could be attractive, such as use in disaster response, device charging and lighting in electricity-poor regions of the world. Perovskite solar cells also have the highest power to weight ratio amongst viabale photovoltaic technologies.

“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 Martin Green, Director of the ACAP and Ho-Baillie’s mentor. The project’s goal is to lift perovskite solar cell efficiency to 26%.

The research is part of a collaboration backed by $3.6 million in funding through the Australian Renewable Energy Agency’s (ARENA) ‘solar excellence’ initiative.