A novel bifunctional thioarsenate based on unprecedented molecular [Cd4As8Se16(Se2)2]8− cluster anions

Abstract

Exploring and developing new functional inorganic chalcogenides with unique structures is always one of the most important missions in solid-state chemistry, especially those with molecular structures. Herein, a novel quaternary thioarsenate, Cs₂CdAsSe₅, is found to be based on an unprecedented molecular (poly)chalcogenide cluster architecture, which has never been discovered in inorganic chalcogenide systems. This rare windmill-like [Cd₄As₈Se₁₆(Se₂)₂]⁸⁻ cluster is made of four [CdSe₄] and [As(V)Se₄] tetrahedra via corner-sharing Se atoms and Se–Se bonds. Specifically, Cs₂CdAsSe₅ exhibits a remarkable photocurrent response and a large computationally predicted birefringence, and the origin of the optoelectronic performance and optical anisotropy is confirmed by detailed theoretical investigation.