Role of Metal-Chloride Anions in Photoluminescence Regulations for Hybrid Metal Halides.

Organic-inorganic hybrid metal halides with emissive organic cations are of great interest due to their structural diversity and interesting photophysical properties. Here, we assemble emissive organic cations (EnrofloH22+) with different metal-chloride anions (Pb2Cl62- to Bi2Cl104- to SnCl62-) to form the new single crystal phases, and thus the photoluminescence properties of the metal halides, including Stokes shift, full width at half-maximum (FWHM), and photoluminescence quantum yield (PLQY) have been studied accordingly. (EnrofloH2)SnCl6·H2O, as an example, possesses narrow FWHM and high PLQY, which are caused by the strong π-π stacking and inter- and intramolecular hydrogen bonds interactions. Compared with EnrofloH22+ cation in solution, the interactions generate a restraining effect and increase the rigid degree of EnrofloH22+ cation in the bulk single crystals. Our work clarifies the photophysical properties of the EnrofloH22+ organic cations by constructing the inter- and intramolecular interactions and boosts the further study of organic-inorganic hybrid metal halides materials with different luminescence mechanisms.