Artificial photosynthesis, or solar water splitting via a photoelectrochemical cell, represents a promising approach to sustainably satisfy escalating global energy demands. Despite much promise, most semiconductor-based photocatalytic devices suffer from insufficient absorption of solar insolation, preventing widespread utilization of this vast solar resource. We address this disparity by augmenting traditional semiconductor-based (Cu2O) device architectures with plasmonic core@dielectric shell (Au@SiO2) nanoparticles. Plasmonic nanoparticles possess tunable optical properties throughout the visible spectrum due to a phenomenon known as localized surface plasmon resonance (LSPR), enabling these noble metal nanostructures to serve as optical antennae within photoelectrochemical cells. Integration of these plasmonic elements within the Cu2O photocathode imparts a three-fold enhancement in photoelectrochemical activity within the plasmonic device as a result of increased light absorption within the Cu2O nanowires. Photoluminescence studies coupled with optical simulations via the discrete dipole approximation (DDA) confirmed that the increased visible-light absorption in the plasmonic device was due to the electromagnetic near-field enhancement mechanism. The insights gleaned from these studies are relevant to various plasmonic-metal/semiconductor systems and further the eventual establishment of general plasmonic design rules for constructing more efficient photoelectrochemical devices.

Plasmon-enhanced Cu2O photocathodes for solar water splitting

249th National Meeting (2015)

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