A Layered Hybrid Rare-Earth Double Perovskite-Type Molecule-Based Compound with Electrical and Optical Response Properties

A layered hybrid rare-earth double perovskite-type molecule-based compound (3HQ)4[RbEu(NO3)8] (3HQ = 3-Quinuclidinone cation, 1) was synthesized. It undergoes a reversible phase transition and switchable dielectric constant behavior above room temperature (phase transition point Tc = 438 K). Variable-temperature single-crystal structure analyses reveal the order-disorder transition of the organic cation and the distortion of the anionic framework, are the origin of the phase transition. Meanwhile, this arouses dielectric transition between “switch off” (low-dielectric state) and “switch on” (high-dielectric state), resulting in a switchable property of dielectric constant. Moreover, photoluminescence property of 1 under a UV excitation was also identified. The colourless sample emits a bright orange red photoluminescence with quantum efficiency (QE) yield of 20.53 %. This finding of hybrid rare-earth double perovskites with prominent phase transition and photoluminescence property will expand a feasible pathway for designing multifunctional smart stimuli-responsive materials.