Au–Pt core–shell nanoemitters on silicon for photoelectrochemical solar energy conversion

Electrochemical self-organization principles were applied for nanofabrication of Au–Pt core–shell nanoemitters on pre-structured porous SiO2/Si interfaces. The silicon templates were fabricated by oscillatory photocurrent cycles in fluoride containing solutions, permitting subsequent local electrodeposition of rectifying metal heterocontacts into the pores. Enhanced light absorption of this Au–Pt/SiO2/Si nanoarchitecture is deduced from Mie scattering analysis and Finite Difference Time Domain simulations in dependence on the Pt-shell thickness. Test operation as photoelectrochemical cells in I−/I3− redox electrolytes shows conversion efficiencies of 11.6% improving thus the performance of the cells without plasmonic enhancement. It is thereby proven that self-organized electrochemical conditioning on the nanoscale can be successfully applied for preparation of advanced photovoltaic systems, opening thereby new avenues for low-cost production also of solid-state devices.