Spark plasma sintering of Cu2SnS3 powders synthesized by mechanical alloying

Abstract

Earth-abundant and nontoxic absorber materials have been extensively studied for thin-film solar cells. One of the most viable candidate materials for solar absorber applications is Cu2SnS3 (CTS). The feasibility of producing fully dense CTS materials by combining mechanical alloying (MA) and spark plasma sintering (SPS) is reported for the first time. X-ray diffraction analysis revealed the formation of the CTS compound, with a monoclinic structure, after 2h of MA. SPS consolidation of the CTS powder particles was performed at 600°C yielding high densification without much sulfur loss or oxidation. Optical band gaps ranging from 1.34eV to 1.11eV were estimated with diffuse reflectance measurements. The approach used constitutes a simple and economic alternative to conventional sintering techniques already used to prepare thin-films from nanopowders and, in the near future, it is believed that SPS will be able to produce dense absorber layers of CTS for thin-film solar cells.