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Description
In this work, we report the fabrication of a novel aeromaterial based on Fe₃O₄, synthesized via spray pyrolysis and drop infiltration techniques. The process involves the deposition of Fe₃O₄ onto sacrificial ZnO microtetrapod templates. The precursor solution consisted of 0.15 M FeCl₃ dissolved in ethanol. For the spray pyrolysis approach, a custom-built setup was used, with the substrate maintained at 480 °C and the deposition time being 3 minutes, yielding Fe₃O₄ thin films with an approximate thickness of 400 nm. In the drop infiltration method, 150 μL of precursor solution was droped on the ZnO microtetrapods substrate at a rate of one drop per second, at room temperature. The samples were subsequently annealed at 500 °C for one hour in air in order to improve the material’s crystallinity and eliminate residual chlorine. The ultraporous structure of Fe₃O₄ was achieved by selectively etching the ZnO templates using 0.1 M citric acid. The final three-dimensional architecture was obtained through a controlled drying process in a lyophilizer at –55 °C for 8 hours. The structural characterization of the material using XRD showed the presence of both Fe3O4 and ZnFe2O4 mixed phases. The photoelectrical characterization at 150 K and 300 K and excitation using an Nd:YAG laser (355 nm) has shown the remanent photoconductivity, with a more pronounced effect at lower temperatures.
