Emerging Semiconductor Materials for Photoelectrochemical Water Splitting

Lead by Prof. David Tilley

We investigate “emerging” semiconductor-based materials for photoelectrochemical water splitting, with a focus on those materials comprised of Earth-abundant elements and fabricated using simple and scalable methods. Thus far we have targeted copper-based materials, due to the abundance of copper and facile preparation methods for copper oxides and copper sulfides. We recently reported a favorable heterojunction partner (CdS) for emerging material CuO (Figure 1) that enabled record photovoltages to be obtained. The materials are characterized under simulated AM 1.5 G solar irradiation (100 mW/cm2). The current density–voltage characteristics are shown in Figure 2, where the onset of hydrogen producing photocurrents occurs at approximately +0.45 V/RHE and 1.68 mA/cm2 of photocurrent are produced at 0V/RHE. This level of photocurrent would correspond to ~2% solar-to-hydrogen (STH) efficiency in a tandem cell where the electrical bias is provided by an additional photovoltaic junction.

figure current density
Figure 2: Current density-voltage curve of a CuO/CdS heterojunction photocathode in pH 7 phosphate buffer under chopped simulated AM 1.5 G solar radiation (100 mW/cm2). (Chemistry of Materials, 2017)