Humidity sensing of Mg doped MCM-41 on silver sputtered thin films

Abstract

The as-synthesized mesoporous silica nanoparticles were doped with varying concentration of xMgCl2 (x = 0 – 1 g). The samples were coated onto silver sputtered interdigitated films (IDEs) on the glass. The comb-shaped interdigitated electrodes were prepared by R.F sputtering at 7.2 × 10−2 mbar with power at 60 W. The thickness of the thin film was around ~ 100 nm. The Mg doped MCM-41 samples were coated on to the IDEs to study humidity sensing at ambient room temperature. The obtained samples were characterized using Fourier-transform infrared spectroscopy (FTIR), Small Angle X-Ray Scattering (SAXS), N2 adsorption–desorption isotherms and High-resolution Transmission Electron Microscopy (HRTEM). The impedance of Mg doped MCM-41 (0.5) sample changed more than four order of magnitude over the relative humidity 11% to 93% RH performed at the ambient temperature 25 °C. In the whole series only xMg–MCM-41, where x = 0.5 was the best candidate for sensing humidity. Studies of impedance show that the combination of Mg doped MCM-41 on indigenously prepared interdigitated electrodes are a step towards the manufacturing process of high-performance humidity sensors.