Dual-Defect Synergic Cr_xTi_yO₂ Nanostructures Boosting High SERS Performance.

Area of Science:

• Materials Science
• Spectroscopy
• Nanotechnology

Background:

• Semiconductor-based surface-enhanced Raman spectroscopy (SERS) substrates are emerging as alternatives to noble metal-based ones.
• Defect engineering, including vacancy creation and elemental doping, is key to optimizing semiconductor SERS performance.
• The synergistic effects of multiple defect types on SERS enhancement remain poorly understood.

Purpose of the Study:

• To investigate the synergistic effects of Ti vacancies and Cr doping in nanostructured Cr_xTi_yO₂ for enhanced SERS.
• To elucidate the mechanism by which dual defects improve SERS signal amplification.
• To develop a novel pathway for designing high-performance semiconductor SERS substrates.

Main Methods:

• Fabrication of nanostructured Cr_xTi_yO₂ with controlled Ti vacancies and Cr doping.
• Characterization of the dual-defect synergistic boosted SERS substrate.
• Detection of methylene blue (MB) and 4-mercaptobenzoic acid (4-MBA) using the developed substrate.
• Density Functional Theory (DFT) calculations to confirm the electronic structure modifications.

Main Results:

• The optimal Cr_x3Ti_yO₂ substrate demonstrated high sensitivity, detecting MB at 10^-11 M and 4-MBA at 10^-8 M.
• The substrate exhibited excellent reproducibility and stability.
• DFT calculations confirmed that dual defects optimize the band structure and enhance carrier separation, promoting charge transfer.

Conclusions:

• Dual defect engineering in Cr_xTi_yO₂ synergistically enhances SERS performance by optimizing electronic properties and charge transfer.
• This work provides a new strategy for designing advanced semiconductor-based SERS substrates through multidefect synergy.
• The findings contribute to the development of sensitive and reliable chemical detection platforms.