Zinc Tin Chalcogenide Complexes and Their Evaluation as Molecular Precursors for Cu₂ZnSnS₄ (CZTS) and Cu₂ZnSnSe₄...

A series of five heteronuclear zinc tin chalcogenide complexes with the general formula [(tmeda)Zn(SnR₂)₂E₃] (1-R, E = S; R = Me, Ph, tBu; 2-R, E = Se; R = Ph, tBu) have been synthesized and characterized by X-ray crystal structure analysis. In all cases, the six-membered ZnSn₂E₃ rings exhibit twist boat conformation. The presence of the molecular structures in solution is confirmed by ¹¹⁹Sn and ⁷⁷Se NMR spectroscopy. Cothermolysis experiments using a mixture of complexes 1-R or 2-R and [(iPr₃PCu)₂(EC₂H₄E)]₂ as a copper source were monitored by thermogravimetry and temperature dependent X-ray powder diffraction to examine the thermolysis reaction. According to Rietveld refinement, the solid residue consists of Cu₂ZnSnS₄ (up to 78 wt %) or Cu₂ZnSnSe₄ (up to 43 wt %) as the main product, respectively.