Chiral Fluorine Engineering in Amine Molecular Design: Toward High-T_c Multifunctional Rare-Earth Hybrid Double...

Chiral organic-inorganic hybrid rare-earth double perovskites represent an emerging multidisciplinary frontier that synergizes structural diversity, rare-earth functionalities, and chirality-driven phenomena. In this study, a chiral F-engineering strategy is developed to synthesize three novel hybrid double perovskites: (Rac-3-DMFP)₂RbEu(NO₃)₆ (Rac-1) and its enantiopure analogues (R/S-3-DMFP)₂RbEu(NO₃)₆ (R/S-1). The intrinsic chirality of enantiomers R-1 and S-1 is unambiguously confirmed by vibrational circular dichroism (VCD) spectroscopy. Compared to the racemic Rac-1, the enantiomeric R/S-1 pair exhibits enhanced functionalities, including reversible phase transitions at elevated temperatures, distinct dielectric anomalies, and superior second-harmonic generation (SHG) responses with SHG intensities surpassing those of conventional NO₃ ^--based perovskites. Comprehensive optoelectronic characterization leveraging the f-f transition of Eu³⁺ ions revealed broad UV absorption (250-400 nm), intense red luminescence (⁵D₀→⁷F₂ at 615 nm), a prolonged fluorescence lifetime (τ = 3.89 ms), and a notable quantum yield (Φ = 32.23%). This work establishes an effective molecular design strategy for exploring and constructing multifunctional organic-inorganic hybrid rare-earth double perovskites, highlighting their potential in advanced optoelectronics and nonlinear optical technologies.