Role of Metal–Chloride Anions in Photoluminescence Regulations for Hybrid Metal Halides

Abstract

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 (Pb₂Cl₆^2- to Bi₂Cl₁₀^4- to SnCl₆^2-) 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.