Rapid humidity sensing activities of lithium-substituted copper-ferrite (Li−CuFe2O4) thin films

In this study, nanocrystalline lithium-substituted copper ferrite (LiCuFe2O4) nanoparticles with high surface area were synthesized by using a facile and cost-effective wet chemical co-precipitation method followed by crystallization at 900 °C. The powder X-ray diffraction pattern endows the crystalline behavior with minimum crystallite size of 13 nm. The scanning electron microscopy image has confirmed an irregular nanoparticles formation where as the transmission electron microscopy image has identified cubical shaped crystals of polycrystalline nature, approved from the respective selected area electron diffraction spectrum. Thin films of LiCuFe2O4 are envisaged as humidity sensors where moderate sensitivity of 2.2 MΩ/% RH towards the entire range of humidity and fast response/recovery time of 7/36 s is obtained. Notably, as-fabricated humidity sensor of LiCuFe2O4 has confirmed ∼99% reproducibility, confirming its chemical stability and mechanical robustness for commercial viability. •Simple and cost effective method has been used to fabricate the humidity sensor.•The prepared material exhibits negligible aging effect and better reproducibility.•Fabricated humidity sensor shows fast response and stability over a long time.