Study on the constant potential electrodeposition of Se-Sb binary semiconductor alloy in DES and its application in photoelectricity

In this study, Se-Sb alloy coatings were successfully fabricated for the first time via constant potential electrodeposition from a choline chloride–ethylene glycol deep eutectic solvent. The correlation between deposition potential and the morphology, composition, crystal phase, optical, and electrical properties of the coatings was systematically investigated. The results showed that as the deposition potential shifted in the negative direction, the fibrous morphology of the coatings initially became denser and subsequently looser. Correspondingly, the Se content first decreased and then increased, while the Sb content exhibited the opposite trend. The crystalline structure was primarily characterized by an amorphous Sb 2 Se 3 phase. Although both the bandgap and photocurrent response initially increased and then decreased with more negative deposition potentials, the coatings consistently exhibited excellent p-type semiconductor characteristics. Chronoamperometry (CA) analysis indicated that the nucleation mechanism of Se-Sb alloys transitioned from diffusion-controlled three-dimensional (3D) progressive nucleation to diffusion-controlled 3D instantaneous nucleation as the deposition potential shifted from −0.45 V to −0.65 V. Furthermore, cyclic voltammetry (CV) analysis revealed an induced co-deposition mechanism: Se was first deposited on the FTO substrate, which subsequently induced the co-deposition of Se and Sb to form the Se-Sb alloy coatings. Finally, a comparison with coatings annealed at 300 °C demonstrated that annealing significantly improved the crystallinity, resulting in the formation of crystalline Sb 2 Se 3 . However, the photocurrent response decreased by a factor of 5.18. These findings suggest that the as-deposited Se-Sb alloy coatings exhibit superior photoelectrical performance compared to their annealed counterparts, highlighting their promising potential for photoelectric applications.