Hot Carrier Generation and Extraction of Plasmonic Alloy Nanoparticles

TLDR: This work experimentally compares the HEI efficiency from Ag, Au, and Ag/Au alloy nanoparticles to TiO2 photoanodes for the photoproduction of hydrogen and finds that the Ag/ au alloy PNPs extend the stability of Ag in water to larger applied potentials while, at the same time, increasing the interband threshold energy of Au.

Abstract: The conversion of light to electrical and chemical energy has the potential to provide meaningful advances to many aspects of daily life, including the production of energy, water purification, and optical sensing. Recently, plasmonic nanoparticles (PNPs) have been increasingly used in artificial photosynthesis (e.g., water splitting) devices in order to extend the visible light utilization of semiconductors to light energies below their band gap. These nanoparticles absorb light and produce hot electrons and holes that can drive artificial photosynthesis reactions. For n-type semiconductor photoanodes decorated with PNPs, hot charge carriers are separated by a process called hot electron injection (HEI), where hot electrons with sufficient energy are transferred to the conduction band of the semiconductor. An important parameter that affects the HEI efficiency is the nanoparticle composition, since the hot electron energy is sensitive to the electronic band structure of the metal. Alloy PNPs are of parti...