An Introductory Review of Carbon Nanotube-Based Sensors: Mechanisms, Fabrication, and Applications

Abstract

Carbon nanotubes (CNTs) have attracted significant attention in sensor technologies due to their exceptional electrical conductivity, mechanical flexibility, and high surface reactivity. This review provides an in-depth overview of CNT-based sensors, covering their working principles, fabrication techniques, and major application areas. We begin by exploring the fundamental mechanisms underlying CNT sensing behavior—such as piezoresistivity, tunneling effects, and percolation conduction—followed by a discussion of common fabrication methods, including solution processing, printing, and composite integration. Key applications are highlighted, including wearable strain sensors for human motion detection, gas sensors for environmental monitoring, and self-sensing materials for structural health diagnostics. While CNT-based sensors offer clear advantages in sensitivity and form factor versatility, challenges such as material uniformity, signal stability, and long-term durability remain. We conclude by discussing future directions and strategies to overcome these limitations, aiming to guide the development of robust, scalable CNT-enabled sensing systems. This review serves as a timely resource for researchers and engineers seeking to understand and advance CNT-based sensor technologies.