High-performance humidity sensor for multipurpose applications by recycling of potato peel bio-waste

This study suggests the development of a biocompatible and eco-friendly humidity sensor fabricated by using a naturally available potato peel bio-waste as the substrate and the humidity sensitive material. Entire fabrication process of this potato peel-based humidity sensor (PPHS) took less than two minutes owing to the facile and handmade patterning of silver interdigitated electrodes on the surface of dry potato peel. The fabricated humidity sensor yielded a high sensitivity (70 kΩ/ % RH) due to the presence of abundant polar hydrophilic functional groups. The achieved results were stable for more than seven days and repeatable data was obtained for three different samples. Furthermore, a quick response/recovery time of 0.96/1.65 s was recorded for nose breathing with a small hysteresis of only 0.21 % for adsorption and desorption process. The sensor exhibited a good linearity (R2 = 0.997) in the practical applications-based humidity sensing range of 40–85 % RH. Efficient use of PPHS was successfully demonstrated in multiple applications including medical diagnosis, skin care, real-time environment monitoring and touchless sensing owing to its biocompatibility and nonhazardous nature. In addition to the above listed multifunctional applications of PPHS, economic use of potato peel in commercial devices can help in recycling the worldwide wastage of this bio-waste.