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DOE OSTI · 1801243

A molecular tandem cell for efficient solar water splitting

Wang, Degao·Hu, Jun·Sherman, Benjamin D.·Sheridan, Matthew V.·Yan, Liang·Dares, Christopher J.·Zhu, Yong·Li, Fei·Huang, Qing·You, Wei·Meyer, Thomas J.
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Abstract

Artificial photosynthesis provides a way to store solar energy in chemical bonds. Achieving water splitting without an applied external potential bias provides the key to artificial photosynthetic devices. We describe here a tandem photoelectrochemical cell design that combines a dye-sensitized photoelectrosynthesis cell (DSPEC) and an organic solar cell (OSC) in a photoanode for water oxidation. When combined with a Pt electrode for H 2 evolution, the electrode becomes part of a combined electrochemical cell for water splitting, 2H 2 O → O 2 + 2H 2 , by increasing the voltage of the photoanode sufficiently to drive bias-free reduction of H + to H 2 . The combined electrode gave a 1.5% solar conversion efficiency for water splitting with no external applied bias, providing a mimic for the tandem cell configuration of PSII in natural photosynthesis. The electrode provided sustained water splitting in the molecular photoelectrode with sustained photocurrent densities of 1.24 mA/cm 2 for 1 h under 1-sun illumination with no applied bias.

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Wang, Degao, Hu, Jun, Sherman, Benjamin D., Sheridan, Matthew V., Yan, Liang, Dares, Christopher J., Zhu, Yong, Li, Fei, Huang, Qing, You, Wei, Meyer, Thomas J.. 2020-06-16. A molecular tandem cell for efficient solar water splitting. https://doi.org/10.1073/pnas.2001753117

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