Moderate temperature sulfurization and selenization of highly stable metal oxides: an opportunity for chalcogenide perovskites

Abstract

Oxide perovskites would provide a convenient precursor for the synthesis of chalcogenide perovskites. However, the stability of oxide perovskites means that there is no driving force for sulfurization or selenization with conventional chalcogen sources. In this work, we show that sulfurization and selenization of highly stable early transition metal oxides are possible by heating in the presence of HfH₂ and S or Se, thereby creating HfS₃ or HfSe₃ as an oxygen sink and producing an oxygen shuttle in the form of H₂O/H₂S or H₂O/H₂Se. The conversion of ZrO₂ into ZrS₃ or ZrSe₃ is supported with thermodynamic calculations and demonstrated experimentally as a proof-of-concept. Subsequently, we demonstrate that BaZrO₃ can be converted to BaZrS₃ at 575 °C, several hundred degrees below previous methods relying on conventional sulfur sources.