A fundamental understanding of hot carrier relaxation in metal nanostructures is essential for realizing their application potential in energy conversion and photocatalysis. Despite previous investigations of the relaxation of hot carriers generated by surface plasmon resonance (SPR) excitation and interband transitions (IBTs), the hot carrier relaxation lifetimes and their associated mechanisms remain unclear. Herein, we demonstrate two distinct hot carrier relaxation channels in gold plasmonic nanostructures. The experimental observations reveal that the hot carrier relaxation is faster following SPR excitation than that from IBTs in gold nanoparticles and nanorods. The experimental results and theoretical calculations indicate that the numerous plasmon-induced hot carriers undergo surface-mediated carrier–carrier scattering in large gold nanostructures, whereas almost all IBT-induced hot carriers experience bulk carrier–carrier scattering. These findings advance our understanding of hot carrier relaxation and contribute to a clearer microscopic description of scattering channels in plasmonic nanostructures.

中文翻译：

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金纳米结构中两种热载流子的弛豫通道


对金属纳米结构中热载流子弛豫的基本理解对于实现它们在能量转换和光催化中的应用潜力至关重要。尽管之前对表面等离子体共振 （SPR） 激发和带间跃迁 （IBT） 产生的热载流子的弛豫进行了研究，但热载流子弛豫寿命及其相关机制仍不清楚。在此，我们展示了金等离子体纳米结构中两个不同的热载流子弛豫通道。实验观察表明，SPR 激发后的热载流子弛豫比金纳米颗粒和纳米棒中的 IBTs 更快。实验结果和理论计算表明，许多等离激元诱导的热载流子在大型金纳米结构中经历了表面介导的载流子-载流子散射，而几乎所有 IBT 诱导的热载流子都经历了散载流子-载流子散射。这些发现促进了我们对热载流子弛豫的理解，并有助于更清晰地微观描述等离子体纳米结构中的散射通道。