Role of post-transition metal (Bi2O3) on the structural, microstructural and humidity sensing behavior of Bi@Zinc ferrites composite for room temperature operatable humidity sensors

The adsorption process is the most significant component of the amazing surface phenomena of that are displayed by bismuth-substituted zinc ferrites. Adsorption is the underlying principle that makes humidity sensors possible. As a result, rare earth-doped ferrites are an excellent choice for use in applications involving humidity sensors. Considering this, the current study involves the preparation of bismuth (Bi3 +) oxide-substituted zinc ferrites by the solution combustion technique. The typical formula for these ferrites is Bi@ZnFe2O4 (x = 0-0.05). An investigation of the influence of the Bi substitution on the structural, microstructural, and humidity characteristics was carried out. Up to 0.2 mol/% dopants, the X-ray diffraction analysis showed evidence of the creation of a cubic spinel structure. The Scherer technique, which has a range of 20 to 39 nm, was used to determine the average crystallite size of the sample. When nanoparticles are included in samples, the total amount of surface area that is necessary to favour adsorption processes in the samples is significantly increased. Micrographs taken using a scanning electron microscope revealed that the surfaces in question had a porous and irregular structure, as evidenced by the existence of holes and pores. The superparamagnetic behavior of the sample was confirmed by vibrating magnetometer. We noticed a decrease in resistance as the relative humidity increased from 11 to 97%, and we saw an increase in the sensing response as the relative humidity increased. Both of these trends were detected over the whole range of relative humidity. It has been determined that the highest humidity hysteresis occurs when the relative humidity is 54%. The amount of time it took for the sensor to respond was timed at 79 s, and the amount of time it took to recover was timed at 91 s. There is not much of a disparity between the sensing response and recuperation time. The higher concentration of Bi i. e 0.03 mol% exhibits excellent humidity sensing behavior. Because Bismuth is non magnetic material, due to this material morphology increases. Morphology increases the humidity behaviour of the samples increases in our results.

Automated summary

This study focuses on the preparation of bismuth-substituted zinc ferrites and investigates the influence of Bi substitution on the structural, microstructural, and humidity characteristics. The results show that the highest humidity sensing behavior is exhibited by samples with a concentration of 0.03 mol% Bi, which is attributed to the non-magnetic nature of bismuth and the morphological changes in the samples.