Physical and electrochemical characteristics of NiFeO thin films as functions of precursor solution concentration

The effects of the precursor solution concentration on the physical and electrochemical characteristics of NiFeO films were studied. XRD patterns confirmed the formation of a spinel cubic crystal structure. FE-SEM images showed a mesoporous morphology. EDAX analysis confirmed a nearly stoichiometric deposition. Optical absorption studies confirmed the direct bandgap energies in the range 2.00–2.27 eV. The films deposited with a 0.25 M solution concentration had the minimum room-temperature electrical resistivity (3.39 × 10 Ωcm). Films deposited with a 0.15 M solution had the maximum specific capacitance values, 591 F g at a scan rate of 5 mV s (CV) and 632 F g at a current density of 0.5 A g (GCD). NiFeO films exhibited specific energy and specific power values of 15.22 W h kg and 225 W kg, respectively, at a current density of 1 A g. Further, these films retained 92.97% of their specific capacitance after 1000 continuous cycles. Graphical abstract: [Figure not available: see fulltext.]