Effect of sulfur precursors on structural, optical, and electrical properties of Cu2SnS3 nanoparticles

Cu2SnS3 (CTS) is an earth-abundant, non-toxic, and eco-friendly semiconductor that makes it promising for various potential optoelectronic applications, including photovoltaics and photodetectors. In this study, the synthesis of CTS nanoparticles by the solvothermal method using different sulfur precursors is reported. The influences of sulfur precursors on the structural, optical, and electrical properties of prepared CTS material are deeply investigated and discussed. Changing the sulfur precursor source has shown noticeable effects on the obtained CTS crystallite size, the formed secondary phases, as well as the CTS nanoparticles morphology. For instance, thiourea is the only sulfur source that was able to produce directly cubic CTS without post-thermal treatment. In contrast, other sulfur sources produce CTS nanoparticles after sulfurization at 580 °C. XRD and transmission electron microscopy (TEM) were employed to study the morphological and structural characteristics of the prepared CTS samples. UV–visible spectroscopy measurements and the Hall-effect technique were used to evaluate the optical and electronic properties of the samples. Changing the sulfur precursors was found to have predominant effects on the CTS nanoparticles’ structural, optical, and electronic properties. Interestingly, CTS nanoparticles with an optical bandgap in the range from 1.4 to 1.7 eV and particle size from 11.21 to 21.23 nm along with the crystallographic phase could be tuned with only changing the sulfur precursor.