Shape-controlled CoFe2O4 nanoparticles as an excellent material for humidity sensing

Abstract

The humidity sensing performance of cobalt ferrite nanoparticles (CoFe2O4 NPs) with controlled morphology obtained via a solution route is reported in this work. The humidity sensing properties of the presented CoFe2O4 NPs ferrite sensor were investigated by exposing it to a broad humidity range of 8-97% at room temperature. CoFe2O4 NPs with spherical, cubic, and hexagonal shapes have been successfully achieved by tuning the growth conditions like reaction time and amount of solvent. These CoFe2O4 NPs exhibit morphology-dependent chemi-resistive humidity sensing behaviors. The highest humidity sensitivity value of ∼590 along with response/recovery value of 25/2.6 s at room temperature was obtained for CoFe2O4 hexagonal (CF-H) shape as compared to CoFe2O4 spherical (CF-S) and CoFe2O4 cubic (CF-C) shapes. Freundlich adsorption isotherm model was well fitted with the experimental results which turned up in support of a plausible humidity sensing mechanism. The morphology-dependent CoFe2O4 nanostructures exhibit promising sensing capabilities which ensure them as a potential candidate for magnetic recording media and next-generation humidity sensors.