Molecule‐Assembled Plasmonic Gold Nanoparticle Network for Piezophototronic and Human Activity Detections

Abstract

Strain‐based complex functionalities in response to external physical stimuli are significant for the development of intelligent robotic systems. Herein, an assembly of gold nanoparticles through ligand interaction with short linker molecule 2‐picolylamine (PA) is developed. With subnanometer spacing between the nanoparticles (NPs), the network exhibits strain sensitive carrier tunneling between them. Based on these NP networks and a lithographically patterned polydimethylsiloxane (PDMS) microstructure, a multistimuli‐responsive tactile sensor is developed that effectively transduces mechanical strain to electrical responses, and can identify variable weights, detect finger touch patterns, and is ultrasensitive to vibrational movements. Physical activities such as jogging, leg movements, and sit‐to‐stand postures are identified using the system. A significantly high gauge factor of 243 ± 10 associated with the Au NP–PA network is recorded. In addition, the sensor exhibits strain‐dependent plasmonic photodetection with a responsivity of 309 mA W−1 at a tensile strain of 3.7%. The multistimuli‐responsive Au NP–PA network demonstrated here opens up new perspectives on the development of intelligent multifunctional systems.