SERS-enhanced piezoplasmonic graphene composite for biological and structural strain mapping

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Thin-film optical strain sensors offer non-electrical deformation mapping with high resolution.
• Graphene-based sensors are emerging for precise mechanical measurements.
• Surface-enhanced Raman scattering (SERS) provides sensitive molecular detection.

Purpose of the Study:

• To develop a highly sensitive optical strain sensor using graphene and metallic nanoislands.
• To investigate the piezoplasmonic effect for strain detection.
• To enable simultaneous electrical stimulation and optical strain monitoring in cellular studies.

Main Methods:

• Fabrication of graphene films decorated with metallic nanoislands.
• Functionalization of nanoisland gaps with benzenethiolate to create SERS hot spots.
• Quantification of strain-induced changes in SERS signal via a plasmonic gauge factor.

Main Results:

• Demonstrated sensing of tensile deformations below 0.04% with a resolution of less than 0.002%.
• Observed attenuation of SERS signal due to strain-induced gap widening and electric field reduction.
• Achieved a highly sensitive piezoplasmonic effect, surpassing conventional mechanical sensors.

Conclusions:

• The developed nanoisland-graphene composite acts as a highly sensitive piezoplasmonic strain sensor.
• The sensor's dual electrical and optical properties allow for integrated cell stimulation and mechanical response monitoring.
• This technology holds promise for advanced biomechanical and materials science applications.