2024-04-19 スイス連邦工科大学ローザンヌ校(EPFL)
＜関連情報＞
- https://actu.epfl.ch/news/energy-scientists-unravel-the-mystery-of-gold-s–3/
- https://www.nature.com/articles/s41377-024-01408-2
結晶性金薄膜からのフォトルミネッセンスにおける量子力学的効果 Quantum-mechanical effects in photoluminescence from thin crystalline gold films
Alan R. Bowman,Alvaro Rodríguez Echarri,Fatemeh Kiani,Fadil Iyikanat,Ted V. Tsoulos,Joel D. Cox,Ravishankar Sundararaman,F. Javier García de Abajo & Giulia Tagliabue
Light: Science & Applications Published:19 April 2024
DOI:https://doi.org/10.1038/s41377-024-01408-2
Abstract
Luminescence constitutes a unique source of insight into hot carrier processes in metals, including those in plasmonic nanostructures used for sensing and energy applications. However, being weak in nature, metal luminescence remains poorly understood, its microscopic origin strongly debated, and its potential for unraveling nanoscale carrier dynamics largely unexploited. Here, we reveal quantum-mechanical effects in the luminescence emanating from thin monocrystalline gold flakes. Specifically, we present experimental evidence, supported by first-principles simulations, to demonstrate its photoluminescence origin (i.e., radiative emission from electron/hole recombination) when exciting in the interband regime. Our model allows us to identify changes to the measured gold luminescence due to quantum-mechanical effects as the gold film thickness is reduced. Excitingly, such effects are observable in the luminescence signal from flakes up to 40 nm in thickness, associated with the out-of-plane discreteness of the electronic band structure near the Fermi level. We qualitatively reproduce the observations with first-principles modeling, thus establishing a unified description of luminescence in gold monocrystalline flakes and enabling its widespread application as a probe of carrier dynamics and light-matter interactions in this material. Our study paves the way for future explorations of hot carriers and charge-transfer dynamics in a multitude of material systems.
