Ternary Heterojunction-Reinforced Room-Temperature Flexible NH₃ Sensor with Enhanced Sensitivity and Ultralow...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Flexible ammonia (NH3) sensors are crucial for continuous monitoring.
• Existing sensors often lack high sensitivity, selectivity, or stability at room temperature.

Purpose of the Study:

• To develop a high-performance, room-temperature flexible NH3 sensing chip.
• To investigate the dual heterojunction enhancement mechanism for improved sensor performance.

Main Methods:

• Fabrication of a flexible NH3 sensor on a PET substrate using Au interdigitated electrodes.
• Synthesis of PPy/(001) TiO2/MXene (PTM) ternary nanocomposites with 3D nanostructures.
• Utilizing dual heterointerfaces (PPy/(001) TiO2 and PPy/MXene) for enhanced sensing.

Main Results:

• The PTM-based sensor achieved a high response (164.42% to 10 ppm NH3) and an ultralow detection limit (5 ppb) at room temperature.
• Demonstrated excellent selectivity, long-term stability, and mechanical durability (1.9% response decline after 500 bending cycles).
• Maintained high sensitivity under high humidity and was successfully applied for food spoilage monitoring and breath analysis.

Conclusions:

• The PTM-based flexible NH3 sensor exhibits superior performance characteristics for room-temperature operation.
• The dual heterojunction design significantly enhances sensor sensitivity and stability.
• The sensor shows strong potential for practical applications in food safety and noninvasive medical diagnostics.