Band Structure Engineering within Two-Dimensional Borocarbonitride Nanosheets for Surface-Enhanced Raman Scattering

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) typically relies on plasmonic metal nanoparticles.
• Developing metal- and plasmon-free SERS platforms is crucial for broader applications.
• Band structure engineering offers a potential strategy to enhance SERS performance.

Purpose of the Study:

• To demonstrate a band structure engineering strategy for metal- and plasmon-free SERS using 2D borocarbonitride (BCN).
• To investigate the charge transfer process and its impact on SERS enhancement.
• To evaluate the potential of BCN as a stable and sensitive SERS substrate.

Main Methods:

• Fabrication of two-dimensional (2D) borocarbonitride (BCN) as a SERS substrate.
• Band structure engineering of BCN to align its conduction band with the LUMO of target molecules.
• Characterization of SERS performance, fluorescence quenching, and stability under various conditions.

Main Results:

• Achieved remarkable SERS performance when BCN's conduction band aligned with the target molecule's LUMO, attributed to Herzberg-Teller coupling.
• Observed efficient charge transfer, leading to fluorescence quenching and enabling sensitive detection of 20 types of analytes.
• Demonstrated excellent thermal (300 °C) and chemical (pH 0-14) stability of the BCN substrate.

Conclusions:

• Band structure engineering is an effective strategy to enhance SERS performance in plasmon- and metal-free semiconductor substrates.
• 2D BCN shows great promise as a robust and highly sensitive platform for detecting trace chemical and bioactive molecules.
• This work provides new insights into utilizing semiconductor properties for advanced SERS applications.