Luminescent hybrid halides with various centering metal cations (Zn, Cd and Pb) and diverse structures.

Organic-inorganic hybrid metal halides have been extensively studied because of their great potential in optoelectronics. Herein, we report three hybrid metal halides (Bmpip)ZnBr, (Bmpip)CdBr, and (Bmpip)PbBr (where Bmpip is 1-butyl-1-methyl-piperidinium, CHN). (Bmpip)ZnBr and (Bmpip)CdBr crystallize in the 2/ space group with zero-dimensional crystal structures with [Br] ( = Zn, Cd) tetrahedra isolated by Bmpip. (Bmpip)PbBr crystallizes in the triclinic space group 1̄ with one-dimensional corrugated chains constructed from face-sharing [PbBr] octahedra. All of the compounds exhibit excellent ambient and thermal stability. Under UV excitation, all three compounds exhibit very broad emissions. Temperature-dependent photoluminescence measurements indicate that the broad emissions of (Bmpip)ZnBr and (Bmpip)CdBr can be attributed to both the organic cations and self-trapped excitons (STEs) and that the emission of (Bmpip)PbBr is assigned to STEs. Density functional theory calculations reveal that the three compounds adopt a direct band gap. This work enriches our understanding of the structure types of hybrid metal halides while revealing their diverse emission mechanisms.