Structural and Physical Properties of Two Distinct 2D Lead Halides with Intercalated Cu(II).

Transition metal cation intercalation between the layers of two-dimensional (2D) metal halides is an underexplored research area. In this work we focus on the synthesis and physical property characterizations of two layered hybrid lead halides: a new compound [Cu(OC-CH-NH)]PbBr and the previously reported [Cu(OC-(CH)-NH)]PbBr. These compounds exhibit 2D layered crystal structures with incorporated Cu between the metal halide layers, which is achieved by combining Cu(II) and lead bromide with suitable amino acid precursors. The resultant [Cu(OC-(CH)-NH)]PbBr adopts a 2D layered perovskite structure, whereas the new compound [Cu(OC-CH-NH)]PbBr crystallizes with a new structure type based on edge-sharing dodecahedral PbBrO building blocks. [Cu(OC-CH-NH)]PbBr is a semiconductor with a bandgap of 3.25 eV. It shows anisotropic charge transport properties with a semiconductor resistivity of 1.44×10 Ω·cm (measured along the -axis) and 2.17×10 Ω·cm (along the -plane), respectively. The fabricated prototype detector based on this material showed response to soft low-energy X-rays at 8 keV with a detector sensitivity of 1462.7 μCGycm, indicating its potential application for ionizing radiation detection. These encouraging results are discussed together with the results from density functional theory calculations, optical, magnetic, and thermal property characterization experiments.