Highly Sensitive TbCrO₃ Capacitive Humidity Nanosensor Prepared by Sol–Gel Combustion

Nanoporous TbCrO₃, a new ferroelectric humidity sensor, was developed by modified sol–gel combustion method at 900 °C. The nanostructured TbCrO₃ underwent characterization through multiple techniques, such as crystalline and phase study by powder X-ray diffractometer, particle size, size distribution, and morphology by transmission electron microscopy, surface area analyzer, and scanning electron microscope and optical analysis were employed by UV–vis diffuse reflectance spectroscopy. These tasks were employed to ascertain the phase purity, size distribution of particles, and the tunable energy photo bandgap of the prepared nanostructures. Diffraction investigations of TbCrO₃ samples brought out exactly and clear in the previous literature peaks of highly crystalline orthorhombic structure. Room temperature ferroelectric loop and high surface area exhibit good dielectric relaxor properties of TbCrO₃ nanoparticles. Not one but two bandgaps values were found at around ∼1.8 and 2.7 eV with the help of K-M function through diffuse reflectance technique. For the first time, it was found to have ultra-high humidity sensitivity. Sensors of TbCrO₃ nanoparticle show excellent humidity sensing behavior in the range of 4%–7%, which promptly increased up to 80% and then reached a stable value.