Selective surface-enhanced Raman scattering in a bulk nanoplasmonic Bi₂O₃-Ag eutectic composite

Abstract

<jats:title>Abstract</jats:title><jats:p>A recent surge of interest in surface-enhanced Raman scattering (SERS) has stimulated the search for new systems that can be utilized to fabricate high-performance optical devices. However, the two-dimensional design of the vast majority of SERS-based assemblies has significantly hindered their real-life applicability, motivating the development of three-dimensional volumetric materials. Here, we report selective SERS observed in a volumetric Bi<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>-Ag eutectic composite obtained by the micro-pulling-down method utilizing directional solidification of eutectics. The enhancement of the Raman signal originates from the localized surface plasmon resonance, LSPR, resulting from silver nanoparticles embedded in the composite. The plasmonic origin of the enhancement is confirmed by characteristic features, such as (i) an enhancement magnitude &gt;10<jats:sup>3</jats:sup>, (ii) the correspondence between the Raman bands’ intensity upon excitation by different wavelengths and the localized surface plasmon resonance (LSPR) intensity, and (iii) the occurrence of overtones, which are absent in the as-grown material that does not exhibit LSPR. The examined Bi<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>-Ag eutectic-based composite is obtained by directional solidification using a simple crystal growth technique. It is the first case of a bulk SERS-active material fabricated by crystal growth techniques, which opens new perspectives towards scalable three-dimensional optical elements with tunable properties based on Raman scattering.</jats:p>

Observation of High-Order Overtones and Combinations in Surface-Enhanced Raman Scattering: The Essential Role in Elucidation of the Chemical Mechanism

“…The demand for contemporary SERS measurements in the range of higher wavenumbers is conditioned by the limit of recent observations of overtones for the second order. , The overtones of higher orders have been recorded only for inorganic species consisting of heavy elements. − For these compounds, they are affected by localized surface plasmon resonance due to small Raman shifts and cannot be considered as true signs of the chemical contribution. A coordinated theoretical and experimental study of intensive high-order modes may be helpful to validate the necessity of including the higher-order Albrecht terms and can give an insight into the anharmonicity and the excited-state dynamics.…”

Epitaxial Growth of 2D Ultrathin Metastable γ‐Bi2O3 Flakes for High Performance Ultraviolet Photodetection

“…The typical Raman spectrum of 2D γ-Bi 2 O 3 flakes on different substrates were collected under a laser excitation wavelength of 532 nm (Figure S5, Supporting Information), which showed four active Raman modes for 2D γ-Bi 2 O 3 flake, including an A 1 mode at 89.8 cm −1 , an E 1 mode at 123.3 cm −1 , an A 2 mode at 313.8 cm −1 , and a weak E 2 mode at 463.2 cm −1 (Figure 4a; Figure S6, Supporting Information). [30,[40][41] The A 1 vibration mode is ascribed to the vibration of Bi atoms and the E 1 , A 2 , and E 2 are ascribed to the stretching modes of BiO bonds. [30,42] Thickness dependent Raman spectra of 2D γ-Bi 2 O 3 flakes were also collected, with sample thickness ranging from 5 to 25 nm (Figure 4a).…”

An overview of surface-enhanced Raman scattering substrates by pulsed laser deposition technique: fundamentals and applications

“…Recently, three-dimensional (3D) nanostructures with high specific surface area are regarded as one of the solutions to promote giant enhancement of SERS [ 68 , 69 , 129 , 130 ]. Furthermore, the local electromagnetic field could be facilitated by additional charge transfer between the metallic NPs and the adjacent 3D nanostructures [ 68 , 69 ].…”