Experimental and theoretical study of Fe doping as a modifying factor in electrochemical behavior of mixed-phase molybdenum oxide thin films

Here, the sol–gel derived spin-coated undoped and Fe-doped molybdenum oxide thin films were investigated. The XRD spectra revealed that the prepared films were crystallized into mixed phases of orthorhombic α-MoO 3 and oxygen-deficient molybdenum oxide (MoO 2.8 ). The FESEM and AFM images showed that the addition of Fe dopant led to the transformation of morphology from shapeless elongated nanoparticles to homogeneously distributed truncated cubic nanoparticles on the surface of the films. Ab-initio calculations were also carried out to qualitatively model the experimentally obtained results related to the electronic properties of the samples. Cyclic voltammetry analysis and electrochemical impedance spectroscopy were applied to explore the electrochemical behavior of undoped and Fe-doped film electrodes. The increase of Fe content noticeably promoted the ion storage capacitance of the films by improving the conductivity of the host oxide and facilitating charge transfer reactions at the electrolyte–electrode interface.