Room temperature humidity sensing performance of polyaniline–holmium oxide composite

Polyaniline-holmium oxide composite was synthesized using in situ chemical polymerization method. The composite was characterized by spectroscopic techniques such as XRD, FTIR and Raman, whereas morphology was studied by FESEM, TEM and the thermal stability by TGA. The composite under study was tested for humidity sensing characteristics, which exhibited a linear behavior of resistivity with rise in relative humidity from 11 to 97% RH. Maximum humidity sensing response was found to be 95% at 97% RH, with the improved limit of detection of 7.68 with that of polyaniline (12.06), along with a fairly response and recovery times of 32 and 46 s, respectively, very low humidity hysteresis loss of 1.2% and a stable performance over a period of 1 month were indeed remarkable. Sensing mechanism of the composite has been discussed using Grotthuss reaction. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.