The choice of the copper concentration favoring the production of stoichiometric CuSbS2 and Cu12Sb4S13 thin films co-electrodeposited on FTO

In order to elaborate stoichiometric CuSbS2 and Cu12Sb4S13 (CAS) thin films by co-electrodeposition on FTO substrates, the copper concentration was varied between 0.015 M and 0.030 M at - 0.98 mV co-electro-deposition potential (vs. saturated calomel electrode (SCE)). After a sulfurization step in a quartz tube at 410 degrees C under an argon flow for 45 min, the samples formed are analyzed by different techniques: The XRD technique has shown the existence of characteristic peaks of the CuSbS2 phase at 28.53, 28.79, 29.73 and 29.99 degrees clearly for the 0.015 M concentration, but this XRD spectrum has shifted to that of Cu12Sb4S13 phase when the copper concentration increases to 0.030 M. Likewise the Raman spectroscopy has indicated the principal peak of CuSbS2 located at 337 cm(-1) on the spectrum of the 0.015 M concentration, but this peak have disappeared for the 0.030 M concentration and was replaced by a new principal peak of Cu12Sb4S13 at 317 cm(-1). This effect was confirmed by the UV-Visible spectrophotometry technique which shows an in-crease of optical gap from 1.46 eV (CuSbS2) to 1.81 eV (Cu12Sb4S13) when the copper concentration passes from 0.015 M to 0.030 M. The morphological study and EDS analysis have proved that the layers CuSbS2 and Cu12Sb4S13 were elaborated with good stoichiometry. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, stoichiometric CuSbS2 and Cu12Sb4S13 thin films were elaborated on FTO substrates using co-electrodeposition. The samples were analyzed by various techniques, revealing a change in the phases formed as the copper concentration increased.