Size-Tunable Covalent Organic Framework Nanoparticles for Assembling One-Dimensional Photonic Crystals With Visual...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• One-dimensional photonic crystals (1D PCs) are sensitive to environmental changes, making them promising for sensing applications.
• A key challenge is linking microscopic analyte-framework interactions to macroscopic optical signals for intuitive detection.

Purpose of the Study:

• To develop a size-controlled synthesis of uniform nanoscale covalent organic frameworks (COFs) for enhanced 1D PC sensing.
• To create a COF-based 1D PC system capable of visual detection and differentiation of volatile organic compounds (VOCs).

Main Methods:

• A stepwise-induced synthesis strategy was employed for size-controlled fabrication of uniform nanoscale COFs (60-80 nm).
• The COF layer was integrated with mesoporous materials, including metal-organic frameworks (MOFs), to create hybrid 1D PCs.
• The optical response of the fabricated COF/MOF 1D PC to various VOC concentrations was analyzed.

Main Results:

• Achieved high-quality, uniform nanoscale COF layers enabling tunable color variations and saturation in 1D PCs.
• Demonstrated excellent compatibility of COFs with other materials, resulting in bright-colored 1D PCs.
• The COF/MOF 1D PC successfully differentiated 12 VOCs and visually detected concentrations from 0-80 g m⁻³ with <1s response time.
• Transferred COF-based 1D PCs to flexible substrates, maintaining visual VOC sensing capabilities.

Conclusions:

• The developed COF-based 1D PCs offer an effective platform for intuitive, real-time visual sensing of VOCs.
• This technology holds significant potential for practical VOC monitoring in demanding industrial environments.
• The integration of COFs with 1D PCs represents a breakthrough in advanced chemical sensing.