Synthesis, characterization and optical properties of selective Co3O4 films 1-D interlinked nanowires prepared by spray pyrolysis technique

The preparation of cobalt oxide (Co3O4) films containing 1-D interlinked nanowires by spray pyrolysis technique using cobaltous acetate (CH3COO)2Co⋅4H2O solutions in 1:1 water–methanol mixture and study of their optical properties are reported in this paper. The films are characterized by using different physical techniques- X-ray diffraction (XRD), UV–Visible and Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The characterization studies showed that the resultant films are impurity free, phase pure with cubic spinel Co3O4 and contain 1-D interlinked nanowires having diameter and length in the ranges of 250–350 nm and 2–10 μm respectively. The resultant films also showed the better values of absorptance (α) = 0.94, emittance (ε) = 0.17 as compared to the data reported in literature. The selectivity of resultant films is found to be 5.529. These films are found to have good prospects for selective solar absorption coatings because their optical properties indicate the red shift of absorption peaks, exhibiting thereby quantum-confined effect and behavior of semiconductor.