Insightful studies of AuCu nanostructures deposited on Ti platform: Effect of rapid thermal annealing on photoelectrochemical activity supported by synchrotron radiation studies

Abstract

In this work, we present the influence of annealing atmospheres during rapid thermal annealing (40 °C/s) on nanostructured Ti platforms modified by 10 nm layer of AuCu alloy obtained via magnetron sputtering. The AuCu/Ti platform annealed under hydrogen atmosphere exhibits the best photoelectrochemical activity under visible light, i.e. 27 times higher photocurrent than for pure Ti dimpled platform, and the lowest reflectance with minimum at ca. 750 nm. Synchrotron radiation studies allow for inspection in three zones, such as the upper (2–3 nm) and deeper (5–7 nm) surface layers as well as the bulk structure (12–15 nm). Taking into account hydrogenated AuCu/Ti platforms gold presence was confirmed in the upper and deeper surface layers as well as in bulk whereas AuxCuy nanoalloy only in the deeper layer. In the case of copper, Cu2O or Cu were distinguished in the upper and deeper surface layers, where Cu+1/Cutot ratio reaches 70 % in the upper layer and drops to about 40 % at a depth of 5–7 nm. Hydrogenation has a positive effect on photovoltaic performance by efficient acceptor–donor configuration of AuCu doping on/into TiO2 semiconductor showing its potential ability as photoanode in solar cells.