Effect of pH treatment on the structural and optical properties of Sn6Sb10S21 thin films facilely synthesized using a spin coating method

Abstract

This study aimed to examine the effect of pH value for the Sn–Sb–S solution on the growth of tin antimony sulfide (TAS) thin films facilely synthesized and deposited on fluorine-doped tin oxide or borosilicate slide glass substrates using a spin coating method. Field-emission scanning electron microscopy (FE-SEM) micrographs confirmed that some aggregated NPs, the distribution of residuals and larger-sized clusters or non-uniform surfaces of thin films on the substrate surface were significantly affected by pH alteration. XRD analysis revealed that the most intense peak of TAS thin films exhibited a monoclinic Sn6Sb10S21 crystal structure with an orthorhombic Sn5Sb2S9 phase. However, the presence of a binary Sb2S3 phase was also observed; its peak intensity gradually reduced with increasing pH value. In addition, the investigation revealed that change in the structural and optical parameters under the alteration of the pH treatment in a solution had a significant impact on the formation, nucleation and growth of the clusters with increasing residuals and non-uniformity of thin film. It could be concluded from the overall results of our demonstration that TAS thin films with adjusted pH treatment can be attributed to the growth of TAS thin films for use as window layers in solar cell devices and may have potential for use in photodetector, optical communication, and optical dispersion devices in the future.