H/F Substitution Induced Enhancement of Phase Transition Temperature and Quantum Yield in Rare-Earth Hybrid Perovskite

Organic–inorganic hybrid perovskites (OIHPs) with switchable properties are believed to be important as stimuli-responsive materials. Herein, we report two ABX2-type OIHPs: [(CH3)3NCH2R]2[Eu(H2O)]2[CH2(SO3)2]4·2H2O (R = H, 1; F, 2) by using [CH2(SO3)2]2– bridged rare-earth (RE) ions. Meanwhile, these self-assembled host–guest compounds display structural phase transition with a dielectric switch and fluorescent response. Notably, H/F substitution enhanced the intermolecular interactions between the anionic host and the cationic guest. This results in skeleton deformation and changes in the spatial arrangement and symmetry of Eu3+. As a result, the phase transition temperature (Ttr) moved up, and the fluorescence quantum yield (FQY) increased by 4.73%. The molecular assembly strategy proposed in this work will benefit the construction of new multifunctional stimuli-responsive materials.