New path to photovoltaics raises possibility of improved efficiency

Developed at Duke University in North Carolina, the technique builds upon research from the 1990s to allow engineers to construct thin-film samples of perovskites, materials of interest to photovoltaic developers because they have the potential to be as efficient as conventional crystalline-silicon solar cells but much cheaper.

The activity of perovskites derives from the properties of complexes of transition metals with organic compounds; these complexes tend to be complex in structure and somewhat unstable, making them difficult to synthesise. This has limited investigation of perovskites to simpler and more robust compounds, such as methylammonium lead iodide (MAPbI₃), the most common perovskite used in research, which can match the efficiency of silicon with a film 100^th of the thickness of a silicon crystal.

"Methylammonium lead iodide has a very simple organic component, yet is a very high-performing light absorber," said Prof David Mitzi, of the department of mechanical engineering and materials science at Duke. "If we can find a new manufacturing approach that can build more complex molecular combinations, it will open new realms of chemistry for multifunctional materials."