Plasmon Induced Resonant Energy Transfer and Hot Electron Injection in Plasmon Enhanced Photocatalysis

Localized surface plasmon resonance (LSPR) is ideal for improving solar energy harvesting because of the strong, tunable absorption and scattering cross sections. The energy stored in the collective electron oscillations can be transferred to a semiconductor, allowing photoconversion at wavelengths near and above the band edge of the semiconductor. In this presentation we will investigate the mechanisms and optimization of plasmon enhanced photocatalysis using a combined transient absorption and action spectrum/IPCE analysis. Specifically, by controlling the spectral overlap, energy band alignment, and thickness of insulating barriers in metal@semiconductor nanostructures the two possible energy transfer pathways, hot electron injection and plasmon induced resonant energy transfer, are mapped out as well as the corresponding charge relaxation dynamics. A connection is made between the initial plasmonic energy transfer measured on ultrafast time scales to the resulting enhancement in photocatalysis, guiding the efficient design of plasmon enhanced photocatalysts.