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

Abstract

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 PbII in acidic media gave rise to the first porous and water‐stable 2D metal halide semiconductor (DHS)2Pb5Br14. 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.

One-Year Water-Stable and Porous Bi(III) Halide Semiconductor with Broad-Spectrum Antibacterial Performance

“…This stability performance is the same as the other DHS-based semiconductor, (DHS) 2 Pb 5 Br 14 , reported recently by our group. 20 To the best of our knowledge, this is record stability for hybrid Bi(III) metal halide semiconductors. 87−93 Gas Sorption Studies.…”

“…Despite the zero-dimensional nature of (DHS)Bi 2 I 8 the presence of DHS cryptand offers a potential accessible space, as we recently demonstrated in the case of the porous 2D (DHS) 2 Pb 5 Br 14 material. 20 N 2 and CO 2 adsorption isotherms recorded at 77 and 195 K in a previously activated solid at 100 °C under high vacuum reveal no sorption (Figure 4b). Remarkably and in marked contrast, H 2 O and D 2 O isotherms recorded at 298 K show a type-I curve at low relative pressure (<0.15 p/p o ), followed by a gradual increase in uptake up to ∼0.8 p/p o and more pronounced adsorption between 0.8 and 0.95 p/p o associated with condensation in interparticle meso-and macroporosity (Figure 4a).…”

“…By comparison, the 1 H-MAS NMR spectrum of neat cryptand acquired under the same experimental conditions showed much border signals (Figure S6). 20 It indicates that the cryptand molecules brought into the porous material lead to highly ordered networks, whereby the local changes in the noncovalent packing interactions between cryptand molecules and bismuth iodide octahedra are expected to contribute to the 1 H NMR line shape. It is further corroborated by analyzing 1 H and 2 H NMR spectra of the same material acquired after exposure to moisture at 85% relative humidity (RH) in the air.…”

“…The corresponding compound belongs to a new family of materials, namely, porous metal halide semiconductors (PMHS). 20 Long-term environmental stability will bring hybrid halide semiconductors not only a step closer to commercialization 21 but render them proper for new applications beyond optoelectronics.…”