Washable Nanostructured Sensing Layer in a Reusable Printed Ammonia Sensor Label

Ammonia (NH₃) in its aqueous solution form is used in various day‐to‐day applications such as laboratory reagents, fertilizers, and household cleaning due to its solubility in water. Hence, it is extremely important to have a large‐scale sensing system to avoid unintended health hazards. In this article, a printed washable TiO₂ nanoparticle (NP) layer‐based sensing solution to detect evaporated ammonia from its aqueous solution has been demonstrated in this regard. The response has a range of 1 to 25% w/v and is found to be considerably linear in the low concentration level of the ammonia solution. The sensitivity is found to be 0.47/% in the linear region. The sensor illustrates considerably easy fabrication, reusability, and gas adsorption on the sensing layer. Printed electrodes are employed on a flexible polyethylene terephthalate substrate with a washable sensing layer. It is observed that the longevity of the electrodes is considerably high. A maximum 7.5% variation in the response is observed for the reused sensor after washing. Further, it is found that the electrodes are stable enough to be used up to 4 months in ambient conditions. The sensor can be useful to monitor the leakage of NH₃ solution in industrial complexes and also in households.