Elaboration and characterization of transparent conductive oxide thin films: influence of layer number and deposition technique on the photocatalytic properties of silver oxide

In this study, Silver Oxide Ag2O thin films of different coating layers of (1, 3 and 5 wt%) were deposited on glass substrates using both sol gel spin and dip coating techniques, annealed at 500 °C for photo-catalysis activity. The structural, morphological, optical and electrical characteristics of these films have been studied by different characterization techniques. The XRD analysis revealed that all films crystallize in the hexagonal Ag2O phase with a preferred orientation along the (011) direction, confirming their polycrystalline nature. These findings were further confirmed by IR spectroscopy. The average crystallite size of dip and spin coated films increasing from 51.33 to 60.55 nm and from 49.31 to 61.9 nm, respectively, with increasing coating layers. SEM images showed the formation of spherical nanoparticles with relatively large and non-uniform grain sizes, attributed to the large ionic radius of silver oxide. While EDX results confirmed the presence of Ag and O elements in all samples. The UV-visible analysis indicated the decrease in the energy gap as the number of coating layers increased: from 3.95 to 3.86 eV for spin coated films and from 4.1 to 3.67 eV for dip coated films. Hall Effect measurements showed Ag2O particles with 5 coating layers explains the enhanced capacitance which gives good electrical conductivity. Where the 5 dip coated layers sample showed a high photo-activity (89.47%) after 6 hours compared to 5 spin coated layer thin films (87.7%) for the same duration.