Abstract

HERNANDEZ-GUZMAN, F. et al. A simple solution method to prepare VO2:Co²⁺ precursors for thin film deposition by solution-processing method. Biotecnia [online]. 2023, vol.25, n.2, pp.146-152.  Epub Aug 25, 2023. ISSN 1665-1456.  https://doi.org/10.18633/biotecnia.v25i2.1886.

Solution-processing is a low-cost solution method to prepare a variety of organic or inorganic thin films. For metal oxide compounds, a solution-processing solution of an organometallic compound is frequently used as a precursor to be spin coated, followed by a thermal annealing to form metal oxide. In this work, vanadium oxide powders are obtained from a simple acid-base reaction, and then they are dispersed in isopropyl alcohol to form a solution for spin-coating. Different amount of cobalt salt are also added together with VOx into isopropyl alcohol to form VOx:Co2+ solutions. After thermal annealing at 200 °C, continuous transparent thin films are obtained. Optical, structural, morphological and chemical binding energies of those films are analyzed. It is found that amorphous VO2:Co2+ compound is formed in those films with V:Co atomic ratios between 6.6:1 and 1.6:1. Optical absorption onsets of those films are around 2.3 eV. An interesting interconnected porous morphology is observed when the atomic ratio of V:Co is around 4.9:1. It is concluded that porous amorphous cobalt doped vanadium oxide thin films can be obtained from a spin-coating process at low annealing temperature from a simple solution without any complex agent.

Keywords : cobalt doped vanadium oxide; spin-coated thin films; porous morphology; solution processing without ligands.

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