The quest for economic, large-scale hydrogen
production has motivated the search for new materials and device
designs capable of splitting water using only energy from the sun.
Here we introduce an all solution-processed tandem water
splitting assembly composed of a BiVO4 photoanode and a
single-junction CH3NH3PbI3 hybrid perovskite solar cell. This
unique configuration allows efficient solar photon management,
with the metal oxide photoanode selectively harvesting high
energy visible photons, and the underlying perovskite solar cell
capturing lower energy visible-near IR wavelengths in a single-pass
excitation. Operating without external bias under standard AM
1.5G illumination, the photoanode−photovoltaic architecture, in conjunction with an earth-abundant cobalt phosphate catalyst,
exhibits a solar-to-hydrogen conversion efficiency of 2.5% at neutral pH. The design of low-cost tandem water splitting
assemblies employing single-junction hybrid perovskite materials establishes a potentially promising new frontier for solar water
splitting research