Interesting dimensional transition through changing cations as the trigger in multinary thioarsenates displaying variable photocurrent response and optical anisotropy

Due to the intriguing component variability and structure-property flexibility, lone-pair cation-based chalcogenides have garnered substantial interest in recent years. Herein, two new multinary thioarsenates, Cs 2 ZnAs 4 S 8 and [(NH 4 )Cs]CdAs 4 S 8 , were successfully discovered via a surfactant-thermal reaction. Both of them possess identical stoichiometry 2-1-4-8, but they exhibit surprisingly different structural features. Cs 2 ZnAs 4 S 8 demonstrates a three-dimensional (3D) [ZnAs 4 S 8 ] 2− framework made from the corner-sharing [ZnS 4 ] tetrahedra and one-dimensional (1D) [As 4 S 8 ] 4− chains, whereas [(NH 4 )Cs]CdAs 4 S 8 exhibits a two-dimensional (2D) [CdAs 4 S 8 ] 2− layer constructed from the corner-sharing [CdS 4 ] tetrahedra and tetranuclear [As 4 S 8 ] clusters. Photoelectric measurements display that Cs 2 ZnAs 4 S 8 has higher photogenerated electron-hole pair separation efficiency than [(NH 4 )Cs]CdAs 4 S 8 under visible light irradiation. Moreover, both of them show large optical anisotropy (Δ n > 0.17 at 1064 and 2050 nm), while the low dimensional structure is more conducive to enhancing the optical anisotropy based on the theoretical calculations. These findings will provide inspiration for the exploration of multifunctional chalcogenides. Two novel quaternary thioarsenates Cs 2 ZnAs 4 S 8 and [(NH 4 )Cs]CdAs 4 S 8 with intriguing dimensional transition have been discovered for the first time, which display variable photocurrent response and optical anisotropy.