Metal-Organic Framework/Au Core/Shell Nanocubes for Spatially Aligned Molecular Analysis and Molecular-Fingerprint...

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Controlling molecular spatial configuration on metal surfaces is crucial for quantitative Surface-Enhanced Raman Scattering (SERS).
• Existing methods for achieving controlled molecular arrangements for SERS are not well-established.
• Metal-organic frameworks (MOFs) offer potential for precise molecular organization.

Purpose of the Study:

• To develop a platform for quantitative SERS by controlling molecular spatial configuration.
• To synthesize and characterize zeolite imidazole framework-8 (ZIF-8)/Au core/shell nanocubes (ZACS NCs) for SERS applications.
• To investigate the SERS signal generation and quantitative capabilities of the ZACS NCs.

Main Methods:

• Synthesis of ZIF-8/Au core/shell nanocubes (ZACS NCs) using ZIF-8 as a template.
• Uniform gold nanoshell deposition on ZIF-8 nanocubes facilitated by (100) facets and CTAC.
• Characterization of ZACS NCs, including analysis of the interfacial Au/Zn alloy layer.
• Single-particle and micro-Raman spectroscopy to analyze molecular vibrational modes and laser polarization dependence.
• Correlation of particle concentration with SERS intensity to verify quantitative signal generation.

Main Results:

• Uniform ZIF-8/Au core/shell nanocubes (ZACS NCs) were successfully synthesized.
• An interfacial Au/Zn alloy layer modulated the plasmonic properties of the ZACS NCs.
• Raman moieties of 2-methylimidazole (2-mIM) ligands exhibited laser polarization angle dependence.
• Highly linear relationships between particle concentration and SERS intensity were observed for ZIF-8 vibrational moieties.
• The ZACS NCs demonstrated effective detection and differentiation of various targets using 2-mIM ligand peaks.

Conclusions:

• The spatially aligned and periodic molecular configuration within ZIF-8/Au nanocubes enables quantitative SERS signals.
• ZACS NCs represent a versatile plasmonic porous material for advanced sensing applications.
• This approach opens new possibilities for designing materials for precise molecular arrangement and enhanced spectroscopy.