Perovskite solar cell technology has made great strides over the past few years, with a hybrid cell made up of layers of different perovskite materials recently hitting a reported peak efficiency of 26 percent. Now researchers at the Australian National University (ANU) have developed a new manufacturing technique that boosts the efficiency of both perovskite and perovskite-silicon tandem cells.

From humble beginnings of under four percent efficiency in 2009, solar cells made with crystalline perovskite materials have shot to well over 20 percent this year. Not only that, they're cheaper and easier to make than silicon cells, and flexible enough for potential spray-on applications. But ANU researchers say that working in tandem, the two materials can pool their strengths to create a better solar cell.

"The prospect of adding a few additional processing steps at the end of a silicon cell production line to make perovskite cells is very exciting and could boost solar efficiency from 25 per cent to 30 per cent," says Dr Tom White, lead author of the study. "By combining these two cells, the perovskite cell and the silicon cell, we are able to make much better use of the solar energy and achieve higher efficiencies than either cell on its own."

To build in that boost, the ANU team's new recipe calls for a pinch of the element indium to be added to one of the cell's layers, which is claimed to result in a 25 percent increase in its power output. With perovskite better at converting visible light into electricity, and silicon more efficient in the infrared part of the spectrum, a combination of both is a promising path going forward.

"We have been able to achieve a record efficiency of 16.6 per cent for a semi-transparent perovskite cell, and 24.5 per cent for a perovskite-silicon tandem, which is one of the highest efficiencies reported for this type of cell," says White.

The research was published in the journal, Advanced Energy Materials.

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