Chromic materials for responsive surface-enhanced resonance Raman scattering systems: a nanometric pH sensor

Area of Science:

• Nanotechnology
• Spectroscopy
• Chemical Sensing

Background:

• Surface-enhanced resonance Raman scattering (SERRS) offers high sensitivity for chemical detection.
• Chromic materials can change optical properties in response to environmental stimuli.
• Integrating chromic materials with metal nanostructures presents challenges.

Purpose of the Study:

• To report the use of chromic materials for responsive SERRS-based nanosensors.
• To demonstrate the potential of nano-chromic SERRS for ultrasensitive optical sensing.
• To fabricate an ultrasensitive pH optical sensor using methyl yellow.

Main Methods:

• Fabrication of nano-chromic SERRS nanosensors.
• Utilizing methyl yellow as a halochrome indicator.
• Employing computational calculations to address integration challenges.
• Measuring SERRS and surface-enhanced Raman scattering (SERS) spectra.
• Correlating SERRS signals with proton concentration.

Main Results:

• Demonstrated the potential of nano-chromic SERRS for pH sensing.
• Successfully fabricated an ultrasensitive pH optical sensor.
• Established a strong correlation between SERRS and proton concentration (pH 2-6).
• Achieved high sensitivity with femtolitre volumes and near single-molecule detection.

Conclusions:

• Chromic materials are effective for responsive SERRS nanosensors.
• The developed methyl yellow-based sensor is ultrasensitive for pH detection.
• Resonance Raman conditions enable femtolitre volume sensing and single-molecule sensitivity.