Graphene Oxide/Zinc Phthalocyanine Selective Singlet Oxygen Visible-Light Nanosensor for Raman-Inactive Compounds

Area of Science:

• Materials Science
• Analytical Chemistry
• Spectroscopy

Background:

• Surface-enhanced Raman spectroscopy (SERS) typically requires specific analyte properties for detection.
• Detecting Raman-inactive compounds via SERS has been a significant challenge in chemical analysis.
• Oxidative platforms can facilitate SERS detection of a broader range of analytes.

Purpose of the Study:

• To develop a novel phthalocyanine-based hybrid nanofilm for SERS applications.
• To utilize the hybrid nanofilm as an oxidative platform for detecting Raman-inactive compounds.
• To enhance the sensitivity and scope of SERS analysis.

Main Methods:

• Fabrication of a hybrid nanofilm via self-assembly of zinc(II) 2,3,9,10,16,17,23,24-Octa[(3',5'-dicarboxy)-phenoxy]phthalocyaninate (ZnPc*) and graphene oxide (GO) using zinc acetate.
• Characterization using atomic force microscopy, UV-vis, and fluorescence spectroscopies.
• Assessment of singlet oxygen generation and redox activity using fluorescence probes and tetramethylbenzidine (TMB) oxidation.

Main Results:

• The hybrid nanofilm structure prevents contact quenching, preserving excited triplet states.
• Visible light irradiation of the nanofilm selectively generates singlet oxygen.
• Ultrasensitive SERS detection of oxidized TMB (TMB+1) was achieved using the hybrid nanofilm with silver nanoparticles as hot-spots.

Conclusions:

• The novel phthalocyanine-based hybrid nanofilm serves as an effective visible-light-driven oxidative platform for SERS.
• This approach enables the fine resolution and detection of Raman-inactive compounds.
• The developed platform significantly expands the range of detectable analytes for rapid, ultrasensitive SERS screening.