(3-CF<sub>3</sub>pyH)<sub>2</sub>(3-CF<sub>3</sub>py)Pb<sub>3</sub>I<sub>8</sub>: A Three-Dimensional Metal Halide\nInorganic Framework with Distinctive Kagome Bands

The\nstructural diversity inherent in hybrid organic–inorganic\nmetal halides as a function of the organic cation template can give\naccess to numerous semiconducting materials featuring distinct polyhedral\nconnectivity patterns. Beyond the common corner-sharing pattern of\nhalide perovskites, different motifs can be accessed via the use of\nbulky and asymmetric templates, which can break the corner-sharing\npattern. In this work, we report on the synthesis and characterization\nof a novel three-dimensional hybrid metal halide network, (3-CF<sub>3</sub>pyH)<sub>2</sub>(3-CF<sub>3</sub>py)Pb<sub>3</sub>I<sub>8</sub>, featuring a buckled decorated honeycomb lattice arising from the\ncorner-connected arrangement of [Pb<sub>3</sub>I<sub>8</sub>]<sup>2–</sup> clusters. The compound is an indirect bandgap semiconductor\nwith a bandgap of E<sub>g</sub> = 2.6 eV that exhibits photoluminescence\nvia a trap-assisted mechanism at 77 K. The inorganic cluster topology\ngoverns the electronic properties of the material, whereas the perovskite-like\ncorner connectivity of the clusters gives rise to dispersive bands\nalong certain crystallographic directions. The unprecedented appearance\nof distinctive Kagomé bands, emerging in the DFT calculated\nband structure of the idealized crystal structure, renders this material\na promising candidate for advanced optoelectronic applications.