Artificial photosystems are advanced by the development of conformal catalytic materials that promote desired chemical transformations, while also maintaining stability and minimizing parasitic light absorption for integration on surfaces of semiconductor light absorbers. Here, we demonstrate that multifunctional, nanoscale catalysts that enable high-performance photoelectrochemical energy conversion can be engineered by plasma-enhanced atomic layer deposition. The collective properties of tailored Co₃O₄/Co(OH)₂ thin films simultaneously provide high activity for water splitting, permit efficient interfacial charge transport from semiconductor substrates, and enhance durability of chemically sensitive interfaces. These films comprise compact and continuous nanocrystalline Co₃O₄ spinel that is impervious to phase transformation and impermeable to ions, thereby providing effective protection of the underlying substrate. Moreover, a secondary phase of structurally disordered and chemically labile Co(OH)₂ is introduced to ensure a high concentration of catalytically active sites. Application of this coating to photovoltaic p+n-Si junctions yields best reported performance characteristics for crystalline Si photoanodes.

Nature Materials (2016) doi:10.1038/nmat4794
Received 03 March 2016 Accepted 04 October 2016 Published online 07 November 2016

http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat4794.html