Flexible tactile sensors based on gold nanoparticles-precipitated carbon nanotubes with low contact resistance and high sensitivity

Flexible tactile sensors are receiving considerable interest due to their potential in diverse fields, including physiological monitoring and wearable electronics. Despite numerous studies to broaden their practical use, it remains difficult to simultaneously attain high sensitivity and a wide-range pressure detection. In this study, we have fabricated a tactile sensor with highly porous three-dimensional conductive architecture based on carbon nanotubes (CNTs) functionalized with gold nanoparticles (AuNPs). The zero-dimensional AuNPs, directly precipitated onto the CNT surface, exerted minimal effect on the sensor's initial resistance. Upon applying pressure to the tactile sensor, the contact resistance among the AuNPs-precipitated CNTs changes significantly, resulting in a high sensitivity of 23.23 kPa^-1 in the low-pressure range (0.05-500 kPa) and 11.06 kPa^-1 in the high-pressure range (500-1125 kPa). The sensor also exhibits outstanding sensing characteristics, including low hysteresis and excellent repeatability. Leveraging these advantages, the sensor has successfully detected pulse wave signals, neck/jaw muscle movements, and walking motions, confirming its practical applicability in wearable healthcare technologies.