Thermodynamics and kinetics insight into reaction mechanism of Cu₂ZnSnSe₄ nanoink based on binary metal-amine complexes in polyetheramine-synthesized process

This paper reports on the reaction mechanism of Cu₂ZnSnSe₄ (CZTSe) nanoink via a solvent-thermal reflux method using copper (Cu), zinc (Zn), tin (Sn), and selenium (Se) powders as precursors and polyetheramine as a reaction solvent. The formation of CZTSe nanoparticles in polyetheramine began with the formation of binary phase CuSe and CuSe₂ due to the strong catalysis provided by polyetheramine. Finally, ternary crystals of Cu₂SnSe₃ transformed into well-dispersed nanocrystals of Cu₂ZnSnSe₄. The size of the crystals was shown to decrease with reaction time due to the emulsification effect of the polyetheramine epoxy group. The PH value-reaction time curves for single Cu, Zn elements and CZTSe from all participants elements reacted together have a relationship just reversed each other and both multistage feature were observed, which indicates that the CZTSe reaction was dominated by copper and zinc elements. The PH-temperature mechanism demonstrates that the reaction was controlled by the formation of metal-amine complexes, especially, after heating the PH-time variation manner is the same for pure element and all four elements reacted together. To the best of our knowledge, this is the first study on the mechanism underlying CZTSe formation based on the reactivity and stability of reaction species.