‘Breakthrough’ takes perovskite PV to 27+ percent efficiency

Hailed as a breakthrough, scientists at the University of Oxford have developed an ultra-thin solar cell that delivers over 27 percent conversion efficiency. Based on perovskites, the cell stacks multiple, slightly differing layers on top of each other to capture more of the solar spectrum than a single layer can. “We believe that, over time, this approach could enable the photovoltaic devices to achieve far greater efficiencies, exceeding 45 percent,” says Oxford physicist Shuaifeng Hu.

The world’s most advanced commercial solar cells approach 27 percent efficiency as well (not to be confused with module efficiency, which is lower). These silicon-based wafers are roughly 150 micrometers thick. The Oxford perovskite stack, by contrast, is just over one micron thick and flexible so that it can be applied to a wide range of surfaces.

“By using new materials that can be applied as a coating, we’ve shown we can replicate and outperform silicon whilst also gaining flexibility. This is important because it promises more solar power without the need for so many silicon-based panels or specially built solar farms,” says Junke Wang, another researcher who contributed to the development of the new PV technology.

Historically, the Achilles heel of perovskites is durability. The press release doesn’t address this potential issue. However, the material’s efficiency has been independently verified by Japan’s National Institute of Advanced Industrial Science and Technology (AIST), ahead of the publication of a scientific paper detailing the findings later this year.

The Oxford group leader, Henry Snaith, is the co-founder and chief scientific officer of Oxford PV. Founded in 2010 to commercialize perovskite photovoltaics, this company has started large-scale manufacturing of perovskite photovoltaics at its factory in Brandenburg-an-der-Havel, near Berlin, Germany. Its operations involve perovskite-on-silicon tandem solar cells.