Enhanced Colorimetric Detection of Volatile Organic Compounds Using a Dye-Incorporated Photonic Crystal-Based Sensor...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Volatile organic compounds (VOCs) are biomarkers for various diseases.
• Colorimetric sensing offers facile recognition of VOCs, but visual discernment of color changes can be challenging.
• Existing methods often require data amplification for accurate VOC detection.

Purpose of the Study:

• To develop highly sensitive colorimetric sensor arrays for VOC detection.
• To enhance the visual discernibility of color changes upon VOC exposure.
• To enable facile and intuitive VOC identification through pattern recognition.

Main Methods:

• Fabrication of dye-incorporated colloidal photonic crystals (dye-cPhCs) on a wafer scale using spin-coating of silica nanoparticles in a photo-cross-linkable monomer.
• Utilizing gradient shear flow to create densely-packed nanoparticle arrays.
• Leveraging the overlap between the photonic bandgap edge and dye absorption peak for augmented dye absorption.

Main Results:

• The sensor array generates distinct color difference maps for acetaldehyde, acetone, and acetic acid without data amplification.
• Achieved limits of detection of 1 ppm for acetaldehyde, 0.1 ppm for acetone, and 0.02 ppm for acetic acid.
• Demonstrated VOC diagonalization through visually intuitive pattern recognition and principal component analysis.

Conclusions:

• Dye-cPhCs provide a sensitive and visually interpretable platform for colorimetric VOC sensing.
• The developed sensor arrays offer a promising approach for non-invasive disease diagnostics through VOC detection.
• The method allows for direct visual pattern recognition, simplifying VOC analysis.