Acetylacetone as a new fuel for simple combustion sol-gel processing of NiCo₂O₄ nano-porous thin films

Nickel-cobaltite films (NiCo₂O₄) are promising electrodes for a variety of applications, including solar cells and supercapacitors. Therefore, numerous studies have investigated synthesis methods to tailor the properties of this compound for specific applications. In this article, we investigate acetylacetone as a fuel in the combustion process to synthesize NiCo₂O₄ (NCO) films. By X-ray diffraction and Raman spectroscopy, we confirmed the crystallinity and purity of the spinel phase for the deposited films. Furthermore, we investigated the morphology of the films by field emission scanning electron microscopy and found a tendency towards a nanoporous microstructure at higher annealing temperatures. The deposited films exhibit good optical transmission in the near-infrared and visible spectrum. In addition, the band gap decreased slightly from 2.33 eV to 2.2 eV with increasing annealing temperature. The electrical properties were investigated using the hot-probe and four-probe methods. The measurements revealed a p-type semiconductor behavior and a maximum electrical conductivity of 25.8 S.cm⁻¹ for the films annealed at 450°C.