In this paper, we present the effect of varying humidity levels on the electrical parameters and the multi frequency response of the electrical parameters of an organic-inorganic composite (PEPC+NiPc+Cu₂O)-based humidity sensor. Silver thin films (thickness ~200 nm) were primarily deposited on plasma cleaned glass substrates by the physical vapor deposition (PVD) technique. A pair of rectangular silver electrodes was formed by patterning silver film through standard optical lithography technique. An active layer of organic-inorganic composite for humidity sensing was later spun coated to cover the separation between the silver electrodes. The electrical characterization of the sensor was performed as a function of relative humidity levels and frequency of the AC input signal. The sensor showed reversible changes in its capacitance with variations in humidity level. The maximum sensitivity ~31.6 pF/%RH at 100 Hz in capacitive mode of operation has been attained. The aim of this study was to increase the sensitivity of the previously reported humidity sensors using PEPC and NiPc, which has been successfully achieved.

In this study, porous cationic hydrogen (H⁺) conducting polymer blend electrolytes with an amorphous structure were prepared using a casting technique. Poly(vinyl alcohol) (PVA), chitosan (CS), and NH₄SCN were used as raw materials. The peak broadening and drop in intensity of the X-ray diffraction (XRD) pattern of the electrolyte systems established the growth of the amorphous phase. The porous structure is associated with the amorphous nature, which was visualized through the field-emission scanning electron microscope (FESEM) images. The enhancement of DC ionic conductivity with increasing salt content was observed up to 40 wt.% of the added salt. The dielectric and electric modulus results were helpful in understanding the ionic conductivity behavior. The transfer number measurement (TNM) technique was used to determine the ion (t_ion) and electron (t_elec) transference numbers. The high electrochemical stability up to 2.25 V was recorded using the linear sweep voltammetry (LSV) technique.

Herein this study, pure and manganese- (Mn-) doped ZnO (2 wt. %) nanoparticles have been synthesized using the chemical precipitation method and characterized for the photodegradation of methyl green (MG) pollutant dye under natural sunlight. The structural analysis via XRD patterns has revealed that both intrinsic and Mn-doped ZnO (2 wt. %) samples have hexagonal wurtzite structures with appropriate phase purity, clearly indicating the absence of any external impurity. The incorporation of Mn in the host ZnO lattice has decreased the crystallite size (21.10 → 18.76 nm), and nanoparticle-type surface features with sizes in the 50–100 nm range have been observed through FESEM-based surface morphological studies. Both aforementioned observations have merit in providing more active area and a high surface area to volume ratio for photocatalytic reaction. The investigation of photophysical properties indicates that in Mn-doped ZnO nanoparticles, the absorption peak is blue-shifted by 5 nm (365 → 360 nm), due to the widening of the bandgap. The degradation kinetics of MG dye follow the pseudo-second-order kinetics, and the degradation efficiency has been observed to be 62.78% mediated by pure ZnO and 66.44% by Mn-doped ZnO (2 wt. %) photocatalyst under 60 minutes of sunlight irradiation. Specifically, the rate of photocatalytic reaction (K) ~0.01792 min^-1 and [ ]~0.97992 has been achieved for pure ZnO, whereas slightly higher (K) ~0.02072 min^-1 and [ ]~0.97299 have been observed for Mn-doped ZnO, respectively. Conclusively, the synergistic interactions with multiple charge transfer pathways, improvement of e⁻/h⁺ pair charge separation, improved surface area, and efficient generation of hydroxyl radicals are supposed to be responsible for the highly efficient photocatalytic activity of the Mn–doped ZnO photocatalyst for MG dye.