(NH4)4Sn2S6·3H2O: Crystal Structure, Thermal Decomposition, and Precursor for Textured Thin Film

Abstract

Understanding the condensation of the dimeric thiostannate(IV) [Sn2S6]4– to SnS2 is of key importance for the development of solution processing of advanced tin(IV) sulfide based electronic devices such as photovoltaics (e.g., Cu2ZnSnS4, CZTSSe) and thin-film transistors. Here, we report the crystal structure of tetraammonium thiostannate(IV) trihydrate ((NH4)4Sn2S6·3H2O), which can be used as a more environmentally friendly alternative to the hydrazinium analogue in solution processed advanced tin(IV) sulfide based electronic devices, e.g., CZTSSe. Hirshfeld surface analysis shows that crystal bound water molecules play a significant role in the structure and interact strongly with the sulfur atoms in the dimeric thiostannate(IV) complex [Sn2S6]4–. The thermal decomposition and corresponding condensation of ((NH4)4Sn2S6·3H2O) to SnS2 have been studied by TG/DSC-MS and solid-state 119Sn MAS NMR. It involves the formation of the relatively more condensed thiostannate(IV) complex [Sn4S10]4– at 90 °C via eva...