Utility of by-product quantum dots obtained during synthesis of Cu2ZnSnS4 colloidal ink

This manuscript discusses the utilization and evaluation of kesterite modified multicolor quantum dots (QDs) obtained as a by-product during synthesis of photovoltaic kesterite material. It was observed that luminescence and optical properties of these nanocrystals highly depends on many factors such as type of solvent, sulfur source, the concentration of percursors, intercapping ligands and reaction temperature. The investigation indicates that these QDs contain defect levels of copper and tin, that are believed to be responsible for green color luminescence. These QDs are highly stable and maintain their resistance against photodegradation. The maximum quantum yield of these QDs was ∼0.32 and it remains stable for many days. Raman analysis, X-ray photoelectron spectroscopy, and FTIR spectroscopy suggest that most of these QDs contain ZnS and some ZnO due to chemisorbed oxygen. A light emitting diode was fabricated using a solid host containing these QDs.