A High-Performance Si Microwire Photocathode Coupled with Ni–Mo Catalyst
Shaner, M. R., McKone, J. R., Gray, H. B. & Lewis, N. S. Functional integration of Ni–Mo
We have designed and demonstrated
Significance & impact
Top: (a) Scanning-electron micrographs of a silicon
Bottom: Current-density versus potential (J–E) behavior of the
- The design consists of a n+p-Si
microwirearray with a Ni–Mo/TiO2catalyst/light-scattering bi-layer structure. TiO2 light-scattering nanoparticlesare used to simultaneously achieve high fill factors and light-limited photocurrentdensities from photocathodesthat produce H2 (g) directly from sunlight and water. Photoelectrochemicalcharacterization was performed in 1.0 M H2SO4 under simulated 1 Sun AMG1.5 conditions.
- The best-performing
microwiredevices exhibit short-circuit photocurrentdensities of −14 .3 mA·cm−2, photovoltagesof 420 mV, and a fill factor of 0.48, whereas the equivalent planar Ni–Mo-coated Si devices, without TiO2, display negligible photocurrentdue to complete light blocking by the catalyst layer.