Carbon Nanotube-Based Gas Sensors: Sensing Mechanisms, Functional Interfaces, Gas-Specific Performance, and...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Carbon nanotubes (CNTs) are highly investigated nanomaterials for gas sensing.
• Their unique properties (1D geometry, large surface area, tunable electronic character) enable sensitive detection.
• CNTs can transduce trace gas adsorption into electrical signals near room temperature.

Purpose of the Study:

• To provide a system-oriented review of carbon nanotube (CNT)-based gas sensors.
• To link CNT structure, synthesis, fabrication, sensing mechanisms, functional interfaces, and device performance.
• To highlight recent advancements in flexible, wearable, and room-temperature CNT gas sensors.

Main Methods:

• Review of CNT structure, synthesis, and film/device fabrication techniques.
• Analysis of sensing mechanisms: charge transfer, Schottky-barrier modulation, carrier-lifetime effects, field-enhanced ionization.
• Examination of functional interfaces (noble metals, metal oxides, polymers, graphene) and device performance metrics (sensitivity, selectivity, humidity tolerance).

Main Results:

• CNTs enable sensitive gas detection at room temperature.
• Flexible and wearable CNT sensors fabricated on various substrates (polymer, paper, textile) show promise.
• Performance comparison across devices based on target gas, operating conditions, and key metrics.

Conclusions:

• Significant progress in room-temperature and flexible CNT gas sensors.
• Remaining challenges include reproducibility, selectivity, humidity compensation, and power consumption.
• Future directions focus on robust, scalable, and intelligent CNT-enabled sensing systems.