2D template stabilises Perovkite for solar cells

“Right now, we think that this is state-of-the-art in terms of stability,” said Rice engineer Aditya Mohite (right).

The key was to grow its FAPbI₃ from a solution containing a custom two-dimensional perovskite, designed to promote the growth of well-ordered bulk 3D perovskite crystals.

Solar cells made without 2D templating degraded significantly after two days in sunlight and air, said the university, while templated solar cell materials had not started to degrade after 20 days. “By adding an encapsulation layer to the 2D-templated solar cells, stability was further improved to timescales approaching commercial relevance.”

Efficiency, measured in a p-i-n structure, was 24.1%.

Perovskite instability?

“Perovskite crystals get broken in two ways: chemically destroying the molecules that make up the crystal, and structurally by re-ordering the molecules to form a different crystal,” said fellow Rice researcher Isaac Metcalf (left). “Of the various crystals that we use in solar cells, the most chemically stable are also the least structurally stable and vice versa. FAPbI₃ is on the structurally unstable end of that spectrum.”

Rice University worked with Lawrence Berkeley National Laboratory, University of California San Diego, University of Lille, Centrale Lille Institut, University of Artois, Northwestern University, Purdue University, University of Rennes, Brookhaven National Laboratory, University of Washington and Northwestern University.

Further information can be found in the Science paper ‘Two-dimensional perovskite templates for durable, efficient formamidinium perovskite solar cells‘ – full access required payment.