Rb₂CuSb₇S₁₂: Quaternary Antimony-Rich Semiconductor Featuring a Three-Dimensional Open Framework and Exhibiting an...

Metal-rich chalcogenides with unique network architectures are rare but are of considerable interest because of their intriguing physical properties. In this work, a novel quaternary thioantimonate, Rb₂CuSb₇S₁₂, has been discovered by a facile surfactant-thermal reaction. It crystallizes monoclinic space group P1̅ (No. 2) and exhibits a unique Sb-rich three-dimensional (3D) [CuSb₇S₁₂]^2- framework surrounded by charge-compensating Rb⁺ cations. It is interesting to note that the Cu/Sb ratio of Rb₂CuSb₇S₁₂ represents the lowest limit in the quaternary A/Cu/Sb/Q (A = alkali metals; Q = chalcogen) system. Moreover, Rb₂CuSb₇S₁₂ shows rapid response and good reproducibility based on the photoelectrochemical tests. This study opens up opportunities for discovering the desirable physical properties in metal-rich chalcogenides.