Humidity Optical Sensing Through Silica‐Based Network by Sol–Gel Route

ABSTRACT This work aims to develop a low‐cost optical humidity sensor based on a SiO 2 matrix synthesized via the sol–gel process. The choice of silica is due to its capacity to adsorb water molecules, leading to variations in its physical and optical properties. In this preliminary phase, experimental measurements were carried out to characterize the optical behaviour of the material, reducing the humidity over time. As a proof‐of‐concept, the variation of optical transmittance was monitored over time as a function of the reduction of humidity, starting from a humidity‐saturated condition of the silica.