An iron-based chemical can absorb and convert light into electrons with 92% efficiency — making it a promising material for solar cells.

Light-harvesting 'sensitizers' in solar cells are typically made of rare elements, which are expensive to scale up. To find a cheaper alternative, Kenneth Wärnmark at Lund University in Sweden and his colleagues engineered an iron-based sensitizer that captures photons and transfers their energy to electrons in a similar way to those based on rare elements. The sensitizer converts photons with 92% efficiency: 12% better than the previous best sensitizer based on iron.

Some electrons quickly combined with positive charges, limiting the effective current generated. Still, the authors say that using abundant materials such as iron as a sensitizer for photovoltaics opens up possibilities for low-cost solar energy.

Nature Chem. http://dx.doi.org/10.1038/nchem.2365 (2015)