Nat. Mater. https://doi.org/cw5j (2018)

Strategies for replacing fossil fuels in the Earth’s energy cycle use the production of energy carriers from renewable sources — either by photoelectrochemistry or photovoltaic energy production. Devices for both approaches have been presented, but integrating them in a single apparatus with matched performance and without efficiency losses has remained elusive. Now, Ian Sharp and colleagues have come up with a layout that allows light-induced water-splitting and production of electricity simultaneously.

Sharp et al. integrated a transition metal oxide photoanode onto a silicon wafer to form a hybrid photoelectrochemical/voltaic cell with three termini. In this assembly, carriers not used for the photoelectrochemistry can be extracted as electrical current through the third contact, circumventing current mismatches without having a detrimental impact on the hydrogen evolution. This device boosts the overall usable energy output and provides another step toward efficient solar light harvesting.