Enhancement of hot electron flow in plasmonic nanodiodes by incorporating PbS quantum dots.

Enhancement of hot electron generation using plasmonic nanostructures is a promising strategy for developing photovoltaic devices. Here we show that hot electron flow generated in plasmonic Au/TiO2 nanodiodes by incident light can be amplified when PbS quantum dots are deposited onto the surface of the nanodiodes. The effect is attributed to efficient extraction of hot electrons via a three-dimensional Schottky barrier, thus giving new pathways for hot electron transfer. We also demonstrate a correlation between the photocurrent and Schottky barrier height when using PbS quantum dots with varying size and ligand treatments, which allows us to control the electric properties (e.g. band gap and Fermi level, respectively) of the PbS quantum dots. This simple method introduces a new method for further improvement of the power conversion efficiency of thin-film photovoltaic devices.