  In this study, the effect of Sr- and Ni-doping on microstructural,
morphological and sensing properties of ZnO nanorods has been investigated.
Nanorods with different Sr and Ni loadings were prepared using a simple wet
chemical method and characterized by means of scanning electron microscopy
(SEM), X-ray diffraction (XRD) and photoluminescence (PL) analysis. XRD data
confirmed that Sr- and Ni-doped samples maintainsthe wurtzite hexagonal
structure of pure ZnO. However, unlikes Sr, Ni doping modifies the nanorod
morphology, increases the surface area (SA) and decreases the ratio of
IUV/Igreen photoluminescence peak to a greater extent. Sensing tests were
performed on thick films resistive planar devices for monitoring CO and CO2, as
indicators of indoor air quality.The effect of the operating temperature,
nature and loading of dopant on the sensibility and selectivity of the
fabricated sensors towards these two harmful gases were investigated. The gas
sensing characteristics of Ni- and Sr-doped ZnO based sensors showed a
remarkable enhancement (i. e. the response increased and shifted towards lower
temperature for both gases) compared to ZnO-based one, demonstrating that these
ZnO nanostructures are promising to fabricate sensor devices for monitoring
indoor air quality.
