Porous and Water Stable 2D Hybrid Metal Halide with Broad Light Emission and Selective H2O Vapor Sorption

In this work we report a strategy for generating porosity in hybrid metal halide materials using molecular cages that serve as both structure-directing agents and counter-cations. Reaction of the [2.2.2] cryptand (DHS) linker with Pb-II in acidic media gave rise to the first porous and water-stable 2D metal halide semiconductor (DHS)(2)Pb5Br14. The corresponding material is stable in water for a year, while gas and vapor-sorption studies revealed that it can selectively and reversibly adsorb H2O and D2O at room temperature (RT). Solid-state NMR measurements and DFT calculations verified the incorporation of H2O and D2O in the organic linker cavities and shed light on their molecular configuration. In addition to porosity, the material exhibits broad light emission centered at 617 nm with a full width at half-maximum (FWHM) of 284 nm (0.96 eV). The recorded water stability is unparalleled for hybrid metal halide and perovskite materials, while the generation of porosity opens new pathways towards unexplored applications (e.g. solid-state batteries) for this class of hybrid semiconductors.

Automated summary

We have developed a strategy for generating porosity in hybrid metal halide materials using molecular cages as structure-directing agents and counter-cations. The resulting material, (DHS)(2)Pb5Br14, is the first porous and water-stable 2D metal halide semiconductor. It exhibits selective and reversible adsorption of H2O and D2O at room temperature, along with broad light emission. The water stability and porosity of this material present new possibilities for applications in solid-state batteries and other areas.