Al doped Sr and Cd metal oxide nanomaterials for resistive response of humidity sensing.

In this present work, Al–Sr and Al–Cd nano-materials (NMs) were fabricated trough co-precipitation route. The synthesized NMs were subjected to various advanced techniques such as XRD, XPS, SEM, DRS and BET. XRD patterns showed prominent peaks for Al, Sr and Cd elements within the synthesized samples. SEM images depicted nano size agglomerated particles for Al–Sr and tubular layered structure for Al–Cd-NMs with the average particle size in the range from (40–45) nm. The elemental content within the fabricated samples was investigated in detail via XPS technique. Surface area adsorption (SAA) parameters obtained from BET analysis were ∼122.32 m2/g, 162.41 m2/g (surface area), 0.1231 cm3/g, 0.4312 cm3/g (pore volume) and 0.8996, 0.9982 nm (pore size) for Al–Sr and Al–Cd-NMs. Energy band gaps ∼2.58 (for Al–Sr) and 2.53eV (for Al–Cd) were obtained through DRS. Furthermore, the fabricated samples were tested for humidity sensing ability. The NMs were indicated with decreased resistance as (987–344) MΩ and (924–290) MΩ for Al–Sr and Al–Cd respectively. Response/recovery time ∼60s/44s for (Al–Sr) and ∼29s/45s for (Al–Cd) was calculated. Both the samples were found highly stable for a longer period of 105 days (with the time gap of 20 days) with the variation in resistance less than 2%. Stable microstructure, quick response-recovery behaviour and low hysteresis categorize these two NMs well suited for resistive response of humidity sensing at industrial level. [Display omitted] • Al–Sr and Al–Cd nano-materials. • Surface area adsorption. • Humidity sensing. • Response/recovery time. [ABSTRACT FROM AUTHOR]