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 ABX 2 -type OIHPs: [(CH 3 ) 3 NCH 2 R] 2 [Eu(H 2 O)] 2 ­[CH 2 (SO 3 ) 2 ] 4 ·2H 2 O (R = H, 1 ; F, 2 ) by using [CH 2 (SO 3 ) 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 Eu 3+ . As a result, the phase transition temperature ( T tr ) 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.