Fast and Flexible Resistive Humidity Sensors on Quasi-1D Zr _{1– <i>x</i>} Ti _<i>x</i> S ₃ Nanoswords

The transition-metal chalcogenide (TMC) family of materials has proven to be fruitful for applications of low-dimensional crystals and films. While the devices based on them usually require sophisticated production procedures combined with precisely controlled environments and high-resolution lithography, we propose a much simpler and more versatile approach. Here we demonstrate how Zr1–xTixS3 solid solution crystals produced by the chemical vapor transport technique could be easily used for fast, high-response, and robust humidity sensors in all of the available measurement ranges. This material has a monoclinic crystalline structure with a P21/m space group and crystallizes in high surface area, thin, and long sword-like or necktie ribbons. Brief ultrasound treatment in 2-propanol produces an ink that could be used on any kind of substrate, including flexible ones, by drop-casting. We show a sensitivity to water vapor with R/R0 higher than 1000 times with a fast response rate close to 100 ms and low recovery times shorter than 0.95 s. The sensors produced in such a manner are stable in ambient air and do not require specific storage conditions.