Microstructural, optical, and impedance studies of porous Mn-α-Fe2O3/CuO/Ag heterostructures grown using solution-based methods

Here, thin films of porous Mn-α-Fe₂O₃/CuO/Ag were prepared; engaging solely low-cost solution-based methods. The dip-coating of CuO on electrodeposited Mn-α-Fe₂O₃ samples using a 180-day-old Cu-based precursor produced films with inhomogeneous morphology and shallow surface pores. This morphology provided the platform for the drop-casting of Ag nanoparticles on the film's surface to form porous Mn-α-Fe₂O₃/CuO/Ag heterostructures. EDS, XRD, and Raman spectroscopy studies affirmed the film's structural integrity. The bandgap estimated for the Mn-α-Fe₂O₃/CuO/Ag samples was 3.8 % less than the values deduced for Mn-α-Fe₂O₃ films. Mott-Schottky analysis disclosed n-type semiconducting behaviour for the Mn-α-Fe₂O₃ films, which was retained after forming heterostructures with CuO and CuO/Ag. The charge transfer resistance at Mn-α-Fe₂O₃/CuO/Ag film's surface in an electrochemical system was 27 times lower than the approximate values obtained for Mn-α-Fe₂O₃ samples. This research introduces a facile and low-cost approach for fabricating porous Mn-α-Fe₂O₃/CuO/Ag heterostructures with improved properties for photo-base and optoelectronic applications.