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

Abstract

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 (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.

Crystal Sponge Behavior in a Two-Dimensional Rare-Earth Hybrid Coordinate Polymer

“…Therefore, the thermal motion of H 2 O molecule will consume part of the energy absorbed by Eu 3+ , which greatly influences QE through the nonradiative transition . However, there are strong hydrogen bonding interactions between the coordination H 2 O molecules and the free H 2 O molecules in 1 relative to 2 (Figure ), which is performed by Hirshfeld surface and single-crystal analysis . So, the stronger internal molecular interactions in 1 could reduce the thermal movement of the coordinate H 2 O molecules.…”

“…31 However, there are strong hydrogen bonding interactions between the coordination H 2 O molecules and the free H 2 O molecules in 1 relative to 2 (Figure 4), which is performed by Hirshfeld surface and single-crystal analysis. 32 So, the stronger internal molecular interactions in 1 could reduce the thermal movement of the coordinate H 2 O molecules. At the same time, the changes of the distance between the 2D layers may also have effect on the quantum yield.…”

High-Symmetry Structural Phase Transition Triggers a Triple Switch Based on Dielectric, Nonlinear Optics, and Photoluminescence

“…In particular, as a member of the hybrid family, perovskites possess obvious advantages in structure and stability, as well as physical characteristics such as high carrier mobility, high light absorption coefficient, low energy loss, and high quantum efficiency, which make them hotspots in the field of materials research. − Structural phase transition can be induced by adjusting the movement of the organic part and causing skeletal deformation of the inorganic part. Furthermore, the distinctive structural properties of two-dimensional (2D) perovskite materials indicate a variety of application possibilities in the area of solid-state lighting. − Blue-light materials and their light-emitting diodes (LEDs), which display as an essential component of the three primary hues, perform a key role in applications in the fields of lighting and flat panels. The quantum efficiency of green-light, red-light, and near-infrared perovskite materials has recently been steadily increased. , However, blue-light perovskite materials, which are effective and reliable as the final crucial building block for white lighting and full-color display applications, are still lagging behind other light hues in comparison. , Most Pb-based organic–inorganic materials have blue-white photoluminescence properties. , So far, few lead-free 2D organic–inorganic materials with blue photoluminescence have been reported.…”

Structural dimension engineering and high-temperature dielectric–optical switching in fluorine-substituted lead bromide hybrid perovskites

“…26 Fluorine has a similar van der Waals radius to hydrogen, and a diversified fluorinated structural system can commonly remain unchanged compared to its parent but show a significant enhancement in the barrier for orderdisorder transition, thereby increasing the T c . [27][28][29][30][31][32] Specifically, fluorination of an N-fluoromethyldabconium lead iodide hybrid perovskite led to a T c increase of 110 K, comparable with the hydrogen-deuterium isotope effect. 25 It is worth noting that H/F substitution can also be accompanied by the introduction of asymmetric chirality in some particular molecular structures, generating interesting chiroptical properties.…”