Control of tunneling gap between nanocrystals by introduction of solution processed interfacial layers for wearable sensor applications

In this study, we introduce a strategy to introduce solution-processed interfacial layers in nanocrystal (NC) thin films to fabricate high-performance strain sensors. SiO ₂ interfacial layers are chemically introduced in ligand-exchanged Ag NC thin films to increase the tunneling gap or inter-particle distance between each Ag NC. In this way, the charge-transport mechanism is manipulated, leading to unique electromechanical properties with a high gauge factor. All solution-processed strain gauge sensors with high stability, durability, and sensitivity are fabricated. The sensor successfully measured delicate movements such as finger motions, demonstrating its possible application in electronic skin.