Unveiling enhanced humidity sensing in Sb2O3 doped α-Fe2O3 composites

In this study, highly sensitive, and relative humidity ($\text{\%}$ RH) sensing material based on $\alpha$-Fe₂O₃-Sb₂O₃ composite is demonstrated. The composites were prepared using the conventional solid-state reaction route with different atomic weight concentrations of Sb₂O₃ in $\alpha$-Fe₂O₃ (0, 3, 5 & 7%) to assess its impact on humidity sensing. The structural and optical properties of these composites were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, FTIR spectroscopy, and UV–Vis diffuse reflectance spectroscopy. XRD and Raman showed the multiphase nature of these composites. The band gap of the composites increased with the Sb content. These compounds exhibited humidity sensitivity greater than 88% for a lower Sb content. SEM revealed that the porous structure and large surface area of that composite facilitated better interaction with water molecules, which was the key to this improved performance. These results indicate that 3 wt% Sb₂O₃ significantly enhances the humidity-sensing efficiency of $\alpha$-Fe₂O₃, making it an optimal candidate for the development of efficient humidity sensors.