Effect of Light Irradiation on Hot Electron-Mediated Photoreduction of Silver Ions on Single Gold Nanorods without a Reducing Agent

Abstract

This study investigated the hot electron-mediated photoreduction of silver (Ag) ions on gold nanorods (AuNRs) exposed to a silver nitrate (AgNO3) solution under white light irradiation without a reducing agent and the effect of white light irradiation on the structural and spectral changes in single AuNRs. The hot electron-mediated Ag deposition was confirmed to occur upon white light irradiation, producing AuNRs@Ag (core@shell) structures. No noticeable changes in the size of AuNRs@Ag in the transverse and longitudinal directions were observed as compared with bare AuNRs. The Ag deposition on AuNRs led to an increased scattering intensity as well as a blue shift and line width broadening of the localized surface plasmon resonance (LSPR) peak. Additionally, we investigated the effect of using different light-on/off cycle conditions on the LSPR properties during the formation of the Ag layer on AuNRs. Moreover, increasing the AgNO3 concentration resulted in more pronounced LSPR peak shifts. Overall, fundamental information on the effect of the light irradiation method used for the hot electron-mediated Ag deposition without a reductant on the structural and LSPR changes is provided at the single-particle level.