Stete Felix, Kesarwani Shivani, Ruhmlieb Charlotte, Askes Sven H C, Schulz Florian, Bargheer Matias, Lange Holger
Institut für Physik & Astronomie, Universität Potsdam, Potsdam, Germany.
Institut für Physikalische Chemie, Universität Hamburg, Hamburg, Germany.
Nat Commun. 2025 Sep 1;16(1):8168. doi: 10.1038/s41467-025-63327-z.
In addition to enhanced fields and possible charge transfer, the concentration of photothermal energy at the nanoscale is a central feature of plasmon-driven photochemistry. It is well known that light energy can be efficiently concentrated in metal nanoparticles to length scales far below the wavelength of light. Here we demonstrate that the energy absorbed by a gold nanoparticle can be further localized within a bimetallic gold-paladium nanoparticle system by the dissipation of energy into the attached palladium satellite nanoparticles. After pulsed excitation of the gold core, the satellites collect nearly all photothermal energy and heat up by 180 K while the light-absorbing gold core remains much colder. By comparing transient absorption dynamics of a series of bimetallic nanoparticles with a three-temperature model, we can precisely assess the temperatures of the electronic and vibrational subsystems. We find a strong inverted temperature gradient that opposes the direction of energy input and concentrates the light energy at the active catalytic nanosite.
除了增强的场和可能的电荷转移外，纳米尺度上光热能的集中是等离子体驱动光化学的一个核心特征。众所周知，光能可以有效地集中在金属纳米颗粒中，达到远低于光波长的长度尺度。在此，我们证明，通过将能量耗散到附着的钯卫星纳米颗粒中，金纳米颗粒吸收的能量可以在双金属金-钯纳米颗粒系统中进一步局域化。在对金核进行脉冲激发后，卫星颗粒收集了几乎所有的光热能并升温180K，而吸收光的金核则保持相对较低的温度。通过用三温度模型比较一系列双金属纳米颗粒的瞬态吸收动力学，我们可以精确评估电子和振动子系统的温度。我们发现了一个强烈的反向温度梯度，它与能量输入方向相反，并将光能集中在活性催化纳米位点上。
