A fully inkjet-printed transparent humidity sensor based on a Ti₃C₂/Ag hybrid for touchless sensing of finger motion

Inkjet-printing was used to prepare a flexible and transparent humidity sensor with a Ti₃C₂/Ag hybrid as the humidity-sensitive film and poly(diallyldimethylammonium chloride) (PDDA) as the adhesive layer. The sensor demonstrates an ultrahigh sensitivity (106 800%), a rapid response (80 ms), and excellent bending resistance. We demonstrate that an array of sensors can track moving fingers in a non-contact way and map the distance of the fingers away from the sensor surface. Therefore, our humidity sensors have great potential for novel human-machine interfacing such as touchless control of electronics and collision control between robots and humans in a cobot setting.