Chemical bath deposition of Sb2S3 thin films using the mixing solution of SbCl3 and sodium citrate as a novel Sb source for assembling efficient solar cells

Abstract

In this work, Sb₂S₃ thin films were successfully prepared by chemical bath deposition (CBD) using the mixing solution of SbCl₃ and sodium citrate as a novel Sb source. The influence of the solution chemical composition, deposition process parameters, CdS thin film microstructure on the properties of Sb₂S₃ thin films and the photovoltaic performance of the corresponding solar cells was systematically investigated. The CBD growth mechanism of Sb₂S₃ thin films was explored from the thickness increase and the molar ratio evaluation of Sb–O : Sb–S/O. The result revealed that the CBD growth process of Sb₂S₃ thin films was dominated by the nanoparticle formation–adsorption pathway. When the SbCl₃ concentration was 120 mM, the molar ratio of SbCl₃ : sodium citrate : Na₂S₂O₃ : thioacetamide was 1 : 2.3 : 1.5 : 0.5, the growth solution volume was 48 mL, the growth temperature and time were 90 °C and 6 h, and the Sb₂S₃ solar cell with the architecture of FTO/CdS/Sb₂S₃/spiro-OMeTAD:TMT-TTF/Au achieved a power conversion efficiency (PCE) of 7.63%, along with an open-circuit voltage of 0.78 V, a short-circuit photocurrent density of 16.89 mA cm⁻², and a fill factor of 0.58. The PCE of 7.63% was relatively high in Sb₂S₃ solar cells and the application for the mixing solution of SbCl₃ and sodium citrate as the Sb source can open up a broad space for the preparation of antimony chalcogenide thin films.