Size dependent photoemission study by electrochemical coarsening of nanoporous gold

The generation and utilization of hot charge carriers in plasmonic materials have emerged as a topic of significant importance, with profound implications across multiple disciplines, including optoelectronics, photovoltaics, photocatalysis, and sensing. In this study, we investigate the hot electro...

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Bibliographic Details
Published in:arXiv.org 2024-04
Main Authors: Ebrahimi, Fatemeh, Wu, Xinyan, Pfeiffer, Maurice, Renner, Hagen, Mameka, Nadiia, Eich, Manfred, Petrov, Alexander
Format: Article
Language:English
Subjects:
Charge materials
Coarsening
Current carriers
Electron transfer
Electrons
Gold
Hot electrons
Ligaments
Optoelectronics
Photoelectric effect
Photoelectric emission
Photoelectrons
Photovoltaic cells
Quantum efficiency
Thin films
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Summary:The generation and utilization of hot charge carriers in plasmonic materials have emerged as a topic of significant importance, with profound implications across multiple disciplines, including optoelectronics, photovoltaics, photocatalysis, and sensing. In this study, we investigate the hot electron transfer from nanoporous gold (npAu) in dependence of the structure size, utilizing both the nanoscale feature size and the interconnected nature of this material. We employ photoelectron injection from nanoporous gold into the electrolyte under UV illumination as a test electron transfer process. Nanoporous gold thin films with sub-10 nm initial ligament diameter are stepwise coarsened by potential cycles in a photoelectrochemical setup, thereby allowing us to precisely probe the influence of ligament diameter on the photocurrent response. The resulting ligament diameter variations are confirmed by scanning electron microscopy (SEM) analysis. As the ligament diameter increased from 8 to 16 nm, there was a corresponding decrease in quantum efficiency proportional to the inverse ligament diameter squared. Such dependency is expected for electrons excited by surface collisions. For the small ligament diameter of 10 nm we estimate an emission efficiency of excited 6sp electrons as 3.14%, reaching 23% for the surface excited electrons.
ISSN:2331-8422