Un Ieng Wai, Dubi Yonatan, Sivan Yonatan
School of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel.
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel.
Nanoscale. 2022 Mar 31;14(13):5022-5032. doi: 10.1039/d1nr07822d.
Understanding the intricate relationship between illumination and temperature in metallic nano-particles is crucial for elucidating the role of illumination in various physical processes which rely on plasmonic enhancement but are also sensitive to temperature. Recent studies have shown that the temperature rise in optically thick ensembles of metal nanoparticles under intense illumination is dominated by the thermal conductivity of the host, rather than by the optical properties of the metal or the host. Here, we show that the temperature dependence of the thermal conductivity of the host dominates the nonlinear photothermal response of these systems. In particular, this dependence typically causes the temperature rise to become strongly sublinear, reaching even several tens of percent. We then show that this effect can explain experimental observations in several recent plasmon-assisted photocatalysis experiments. Under certain conditions, we show that thermal emission may also contribute to photothermal nonlinearity. This shows that any claim for the dominance of non-thermal electrons in plasmon-assisted photocatalysis must account first for this photothermal nonlinear mechanism.
理解金属纳米颗粒中光照与温度之间的复杂关系对于阐明光照在各种依赖等离子体增强但对温度也敏感的物理过程中的作用至关重要。最近的研究表明，在强光照射下，光学厚的金属纳米颗粒集合体中的温度升高主要由主体的热导率决定，而不是由金属或主体的光学性质决定。在这里，我们表明主体热导率的温度依赖性主导了这些系统的非线性光热响应。特别是，这种依赖性通常会导致温度升高变得强烈亚线性，甚至达到几十%。然后我们表明，这种效应可以解释最近几个等离子体辅助光催化实验中的实验观察结果。在某些条件下，我们表明热发射也可能导致光热非线性。这表明，任何关于等离子体辅助光催化中非热电子占主导地位的说法都必须首先考虑这种光热非线性机制。
