The Effect of Dye Molecules and Surface Plasmons in Photon-Induced Hot Electron Flows Detected on Au/TiO2 Nanodiodes

We report the combined influence of dye molecules and surface plasmons on hot electron flows generated by the absorption of photons. The study was enabled by the deposition of merbromin and rhodamin B on Au/TiO2 Schottky diodes that exhibit connected island-shaped gold thin films. The short-circuit photocurrent and incident photon-to-electron conversion efficiency (IPCE) measured on Au/TiO2 diodes show significant amplification of the photocurrent when the dye molecules are present on the modified Au islands/TiO2, indicating that the combination of dye molecules and surface plasmons increases the energy conversion efficiency. The positions of the IPCE peaks are in good agreement with the absorbance spectrum of the dye molecules and surface plasmons, suggesting that the detection of hot electron flows can be used as a novel sensing mechanism to characterize charge transport through organic-inorganic and metal-oxide interfaces.