Synthesis of La2O3-Cr2O3-SrO nanocomposite by pyrolysis of metal carboxylates; its characterization, DFT studies and significance in humidity sensing

•Nanostructured composite La2O3-Cr2O3-SrO has been first time prepared using an easy and cost-effective method.•Humidity sensing properties of the films were studied at room temperature via less power-consuming technique.•The average sensitivity was found as ∼ 9.369 MΩ/%RH using electrical mode and ∼ 3.604 µW/%RH using optical mode for the entire range of %RH.•Sensing results were ∼ 98% reproducible and DFT studies confirmed them.•The exceptional performance of the reported sensor is accredited to the strong hydrophilicity and highly porous morphology. This article informs the synthesis of La2O3-Cr2O3-SrO nanocomposite by pyrolysis of metal carboxylates as precursors. Various characterization techniques have been used to investigate the morphological, structural, and optical properties in detail. This investigation reveals that the proposed material can be a promising candidate for sensing applications due to its highly porous morphology, very small particle size, and excellent sensitivity. Subsequently, a well-developed film was employed as a humidity sensor considering both the electrical and optical principles. The average sensitivities were observed as 9.369 MΩ/%RH and 3.604 µW/%RH for one-layered films in case of electrical mode and optical mode respectively with response/recovery times as 15/56 s for the entire range of %RH. The sensing results were found ∼ 95.71% reproducible. Also, DFTstudies were performed to confirm the material’s potency. The exceptional performance of the reported sensor is accredited to the strong hydrophilicity and highly porous morphology.