Triethanolamine concentration effect on electrodeposited SnS thin films properties

SnS thin films were electrodeposited onto ITO-coated glass substrates using one-step potentiostatic electrodeposition in a bath solution consisting of tin chloride (SnCl2) and sodium thiosulfate (Na2S2O3) for different concentrations of triethanolamine complexing agent (TEA). For the kinetic study, the charge transfer coefficient alpha(c), the diffusion coefficient D, and the potential dependent cathodic rate k(c) were deduced by analyzing cyclic voltammograms and potentiostatic current transients. The electrochemical study showed that the charge transfer controls the electrodeposition of SnS in the presence of TEA. The effect of triethanolamine addition on the structural, morphological, compositional, and optical properties was studied using XRD, SEM, EDX, Raman, and UV-visible techniques. FV All samples crystallize in the orthorhombic SnS phase. It was found that the addition of TEA not only affects the surface morphology of the films by reducing the grain size, but also slows down the deposition of tin and thus improves the stoichiometry of the film. The vibrational modes of the tin chalcogenides SnS, SnS2, and Sn2S3 helped in the identification of the sample's chemical structure. All samples displayed low transmittance in the visible range, which decreases with the increase of the agent concentration. The band gap was identified to be direct and increases with TEA in correlation with structural parameters. The optimal properties and the stoichiometry were reached for the concentration ratio [Sn:S:TEA] = [1:4:1] and were found in good agreement with the calculated electrochemical parameters.

Automated summary

SnS thin films were electrodeposited using one-step potentiostatic electrodeposition with different concentrations of triethanolamine complexing agent (TEA). The charge transfer coefficient, diffusion coefficient, and potential dependent cathodic rate were deduced from the electrochemical analysis. The addition of TEA influenced the surface morphology and the stoichiometry of the films. The band gap increased with TEA concentration, and the optimal properties were achieved at a specific concentration ratio.