Tuning the Sharing Modes and Composition in a Tetrahedral GeX(2) (X = S, Se) System via One-Dimensional Confinement

[Image: see text] The packing and connectivity of tetrahedral units are central themes in the structural and electronic properties of a host of solids. Here, we report one-dimensional (1D) chains of GeX(2) (X = S or Se) with modification of the tetrahedral connectivity at the single-chain limit. Precise tuning of the edge- and corner-sharing modes between GeX(2) blocks is achieved by diameter-dependent 1D confinement inside a carbon nanotube. Atomic-resolution scanning transmission electron microscopy directly confirms the existence of two distinct types of GeX(2) chains. Density functional theory calculations corroborate the diameter-dependent stability of the system and reveal an intriguing electronic structure that sensitively depends on tetrahedral connectivity and composition. GeS(2(1–x))Se(2x) compound chains are also realized, which demonstrate the tunability of the system’s semiconducting properties through composition engineering.