Unleashing plasmonic hot carriers in a matchstick-shaped heterostructure

Abstract

The dynamics of hot carriers at the interface between plasmonic nanostructures and semiconductor quantum dots presents an innovative way for modulating light–matter interactions at the nanoscale. Utilizing real-time time-dependent density functional theory simulations, this study elucidates the mechanisms underlying the decay of localized surface plasmons and the dynamics of hot carriers within a composite structure comprising a gold nanorod and a Cd₃₃Se₃₃ quantum dot. Our results demonstrate that the interface formation leads to the broadening and red-shift of the localized surface plasmon (LSP) of the gold nanorod. In particular, this LSP is capable of extending into the Cd₃₃Se₃₃ QD. A significant finding of this study is the energy-dependent segregation of hot electrons and holes. At an initial 5.0 fs, hot carriers are absent, yet they commence to appear at 10.0 fs. By 20 fs and 30 fs, the distributions of hot carriers remain largely unchanged. Through LSP decay and the dynamics of hot carriers, our research offers novel insights into hot carrier dynamics of heterostructures.