A new molecule developed by Ohio State University scientists can harvest energy from the entire visible spectrum of light, capturing up to 50% more solar energy than current solar cells. Unlike available photocatalysts, the rhodium-based molecule operates with radiation wavelengths that span the ultraviolet to the red/near-infrared.

The single-molecule rhodium catalyst absorbs photons and stores two electrons to produce hydrogen. A prototype system was tested by shining LED light onto an acid solution containing the active molecule, resulting in hydrogen gas generation. The catalytic process is marked by two stepwise excited-state redox events, which is not typically observed with current homogeneous photocatalysts. The approach is almost 25 times more efficient with low-energy near-infrared light than previous single-molecule systems operative with ultraviolet photons.

The researchers will next examine the use of less expensive alternatives to rhodium and develop a photocatalyst with a longer service life.

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