Ultrafast Dynamics of Photoexcited Hot Carrier Generation and Injection in AgNWs@TiO2@GNS Nanostructures

The generation and injection of hot electrons in plasmonic nanostructures have received a wide-range potential application in the next generation of ultrafast nanophotonics as well as energy harvesting, storage and conversion. In many cases, the energetic carriers with high energy beyond Fermi level are desirable for photochemical reactions due to the tremendous efficient hot electron injection. However, directly electron–electron scattering lifetime observations have few reported and hot electrons generally suffer from a low generation efficiency in conventional plasmonic nanostructures. This paper reports on the fabrication of hybrid AgNWs@TiO2@Au core–shell nanostructures and the investigation of the ultrafast dynamics of their energetic carriers based on interband and intraband excitations through transient absorption spectroscopy measurements. Finally, the different electronic transition processes are discussed in terms of ultrafast decay response, which is necessary to design proper nanostructures aimed at efficient hot electron injection.