Investigations on humidity sensing of nanostructured tin oxide synthesisedviamechanochemical method

Abstract

In this article, nanocrystalline tin oxide powder was prepared by a mechanochemical method. The synthesised powder was characterised using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD shows the crystalline nature of the synthesised material. The crystallite size was estimated using Debye-Scherrer equation and its minimum value was 9 nm. Surface morphologies of the sensing pellets were investigated using SEM. Pellets as well as thick films were used as sensing elements for humidity sensing measurement. Thick film was prepared on alumina substrate using screen printing technique. Solid-state pellets as well as films were subjected to humidity-sensing measurements in a specially designed humidity chamber. Variations in resistance with relative humidity (%RH) were measured. The effects of annealing on the surface morphologies as well as on the sensitivity of the sensor were also investigated. Hysteresis and ageing effects on experimental results were found 60% and 64%, respectively, for the sensing element prepared after annealing at 600 � C.

Humidity Sensing Behavior of Endohedral Li-Doped and Undoped SWCNT/SDBS Composite Films

“…From the sensitivities shown in Figure 8 resistance changes of up to ≈3%/%RH and ≈4%/%RH were calculated for undoped SWCNT/SDBS and Li@SWCNT/SDBS films, respectively. These values are equal or slightly higher than reported for resistive humidity sensors based on other materials, for example, graphene (0.31%/%RH [6]), MWCNT films (up to 1.3%/%RH [39]), MWCNT/PEDOT:PSS composites (≈1.1%/%RH [12]), SWCNTs (≈3%/%RH [40]), SnO2 (≈2–3%/%RH [41]). We assumed that strong interaction between water molecules and SWCNTs/SDBS induced the resistance change in our samples.…”

Wearable CNTs-based humidity sensors with high sensitivity and flexibility for real-time multiple respiratory monitoring

“…Here, the electrical conductivity could be generated by H + ions generated through the dissociation of humidity molecules [ 34 ] that were first chemically adsorbed on the amine surface and increased by the transfer of the generated H + ions through the humidity phase that is physiosorbed, as shown in Additional file 1 : Fig. S13 (Grotthuss chain reaction) [ 34 , 35 ]. Consequently, a higher level of humidity would increase the number of physically adsorbed humidity molecule layers, allowing faster proton hopping among adjacent water molecules in a continuous water layer and increasing the resistance [ 34 ].…”

Hydrothermal Synthesis of Fe2O3 for the Humidity Sensing Application

“…Metal oxides are the promising material for the various applications in the field of electrical and optical device development. Also, to control environmental conditions, metal oxide nanostructures are extensively used as Humidity Sensor [1][2][3]. As a result, it is a challenging task of design a good humidity sensor.…”