论文标题
单等离子体纳米颗粒中的能量分辨飞秒热电子动力学
Energy-Resolved Femtosecond Hot Electron Dynamics in Single Plasmonic Nanoparticles
论文作者
论文摘要
来自纳米级金属的热载体的有效激发和收获是许多新兴的光化学，光伏和超快光电应用的核心。然而，尽管界面和内部等离激元场，激发分布和散射过程之间存在丰富的相互作用，但仍缺乏无处不在的纳米金结构中相关飞秒动力学的直接实验证据。为了探索纳米级结构对这些动力学的影响，我们采用了一种新技术，用于同时进行单血浆纳米颗粒的时间，角度和能量分辨光发射光谱。光电子速度分布揭示了纳米棒和纳米壳的几何形状中的散装弹道热电子传输，没有表面效应的迹象。在〜1-2 eV范围内观察到的能量分辨动力学，并通过动力学鲍尔茨曼理论推断到较低的能量，提供了纳米级金中热载体寿命的首次直接测量。值得注意的是，我们发现具有小至10 nm的尺寸的颗粒是研究内固有金属动力学的示例性平台。
Efficient excitation and harvesting of hot carriers from nanoscale metals is central to many emerging photochemical, photovoltaic, and ultrafast optoelectronic applications. Yet direct experimental evidence of the relevant femtosecond dynamics in ubiquitous tens-of-nanometer gold structures remains lacking, despite the rich interplay between interfacial and internal plasmonic fields, excitation distributions, and scattering processes. To explore the effects of nanoscale structure on these dynamics, we employ a new technique for simultaneous time-, angle-, and energy-resolved photoemission spectroscopy of single plasmonic nanoparticles. Photoelectron velocity distributions reveal bulk-like ballistic hot electron transport in nanorod and nanoshell geometries, with no evidence of surface effects. Energy-resolved dynamics observed in the ~1-2 eV range and extrapolated to lower energies via kinetic Boltzmann theory provide the first direct measurements of hot carrier lifetimes within nanoscale gold. Remarkably, we find that particles with dimensions as small as 10 nm serve as exemplary platforms for studying intrinsic metal dynamics.
