Experimental Observation of the Fully Ferroelectric–Fully Ferroelastic Effect in Multiferroic Hybrid Perovskites

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(30), P. 21120 - 21128

Published: July 22, 2024

Since the concept of "multiferroic" was first proposed in 1968, coupling effect between different ferroic orders has attracted great interest energy, information, and biomedical fields. However, fully ferroelectric-fully ferroelastic never been experimentally observed hybrid perovskites, even though this predicted to exist half a century ago. Realizing such cross-linking effects polarization vectors strain tensors always huge challenge because complex difference these two origins. Here, we report multiferroic with full ferroelectricity ferroelasticity two-dimensional (2D) perovskites based on ferroelectrochemistry. The dynamic molecular reorientations endow (cyclohexanemethylaminium)

Language: Английский

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Quantifying Structural Polarization by Continuous Regulation of Lone-Pair Electron Expression in Molecular Crystals

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(32), P. 22469 - 22475

Published: Aug. 1, 2024

Rational design of structural polarization is vital for modern technologies, as it allows the physical properties functional materials to be tailored. An effective approach governing involves utilization stereochemical lone-pair electrons (LPEs). However, despite recognized significance LPEs in controlling polarization, there remains a lack understanding regarding quantitative relationship between their expression and extent polarization. Here, by using pressure continuously tune LPE expression, we achieve precise control quantification which brings enhanced second harmonic generation (SHG) molecular crystal SbI

Language: Английский

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Pressure treatment enables white-light emission in Zn-IPA MOF via asymmetrical metal-ligand chelate coordination

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Jan. 15, 2025

Metal-organic frameworks that feature hybrid fluorescence and phosphorescence offer unique advantages in white-emitting communities based on their multiple emission centers high exciton utilization. However, it poses a substantial challenge to realize superior white-light single-component metal-organic without encapsulating varying chromophores or integrating phosphor subunits. Here, we achieve high-performance with photoluminescence quantum yield of 81.3% via boosting triplet excitons distribution through pressure treatment Zn-IPA frameworks. A novel metal-ligand asymmetrical chelate coordination is successfully integrated into the after high-pressure over ~20.0 GPa. This modification unexpectedly endows targeted sample new emergent electronic state narrow singlet-triplet energy gap, which effectively accelerates spin-flipping process for boosted population. Time delay phosphor-converted light-emitting diodes are fabricated long time up ~7 s switching off, providing significant advancements time-delay lighting applications. Pressure-treatment can alter optical properties Here authors induce amorphization remains decompression enables efficient narrowing gap.

Language: Английский

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Hydrogen bonding evolution and efficient blue light emission in a series of Zn-based organic–inorganic hybrid metal halide crystals

Science China Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 17, 2025

Language: Английский

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Pressure Engineering on Perovskite Structures, Properties, and Devices

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: 34(27)

Published: March 4, 2024

Abstract As a fundamental thermodynamic parameter, pressure serves as an effective tool to control the structures and properties of functional materials. To date, numerous pressure‐engineering methods have been introduced enhance perovskite devices. This paper comprehensively reviews advances in understanding effects on materials devices, encompassing both low high‐pressure influences. These are categorized into six distinct groups based their underlying mechanisms, detailing evolution from macroscopic microscopic levels, exploring interplay between these characteristics. Finally, current challenges offer insights future prospects for harnessing further develop structures, properties, devices assessed.

Language: Английский

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Vibration‐Dependent Dual‐Phosphorescent Cu₄ Nanocluster with Remarkable Piezochromic Behavior

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(29)

Published: May 1, 2024

Abstract The dual emission (DE) characteristics of atomically precise copper nanoclusters (Cu NCs) are significant theoretical and practical interest. Despite this, the underlying mechanism driving DE in Cu NCs remains elusive, primarily due to complexities excited state processes. Herein, a novel [Cu 4 (PPh 3 ) (C≡C− p −NH 2 C 6 H ]PF ( NC, shielded by alkynyl exhibiting DE, was synthesized. Hydrostatic pressure applied , for first time, investigate DE. With increasing pressure, higher‐energy peak gradually disappeared, leaving lower‐energy as dominant emission. Additionally, crystal exhibited notable piezochromism transitioning from cyan orange. Angle‐dispersive synchrotron X‐ray diffraction results revealed that reduced inter‐cluster distances under brought peripheral ligands closer, leading formation new C−H⋅⋅⋅N N−H⋅⋅⋅N hydrogen bonds . It is proposed these strengthened bond interactions limit ligands′ vibration, resulting vanishing peak. In situ high‐pressure Raman vibrationally resolved spectra demonstrated benzene ring C=C stretching vibration structural source

Language: Английский

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Building New Structural Distortion Descriptors through Pressure Engineering toward Enhanced Violet Emission in 2D Hybrid Perovskite

Advanced Optical Materials, Journal Year: 2024, Volume and Issue: 12(35)

Published: July 16, 2024

Abstract Building an explicit structure‐property relationship for two‐dimensional (2D) hybrid perovskites is critical to guide the synthesis of highly luminescent materials. However, traditional studies are limited deviation individual intra‐octahedron, which fails well reflect collective lattice distortion. Here, a set new structural distortion descriptors associated with inter‐octahedra introduced 2D perovskite (C 7 H 10 N) 2 PbBr 4, that is,(PMA) 4 through pressure engineering. An experimental conclusion reached adjacent Pb displacement, as inter‐octahedron distortion, effective parameter in determining and emission behavior (PMA) under high pressure. Under pressure, exhibits two behaviors, free excitons (FEs) self‐trapped (STEs) emission. Different types four‐Pb‐shaped quadrilateral correspond different emissions: square‐type (only FEs emission), parallelogram‐type (coexistence STEs kite‐type emission). Moreover, enhanced violet at ≈431 nm achieved mild 1.0 GPa, crucial light source medical sterilization. The underlying clarified fundamentally deepens photophysical mechanism , thus facilitating design high‐efficiency luminophores.

Language: Английский

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Origin of Pressure-Induced Nonlinear Optical Property Enhancement in CsGeCl₃ Perovskite: [GeCl₆] Octahedron Distortion and Band Gap Closing

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 12, 2025

Second-harmonic generation (SHG) is the wave–wave nonlinear interaction in doubling wave frequencies, spanning from optics, radio, magnetohydrodynamics, and even middle atmosphere, enhancing SHG efficiency has attracted broad interest both fundamental mechanisms industrial applications. Laser characterized by a second-order susceptibility tensor optical (NLO) crystals, its intensity largely related to lattice distortion. Halide perovskites demonstrate unique photovoltaic optoelectronic properties due their high tunability crystalline electronic structures, which provides great platform investigate NLO properties. Here, we report pressure-driven enhancement all-inorganic lead-free compound CsGeCl3, exhibits considerable with 9.1 times (@ 1030 nm) that of KH2PO4 at ambient pressure. Upon compression 1.07 GPa, further gains ∼3 times, setting record-high under pressure (HP). Concerning limitations traditional powder measurements, developed new single-crystal angle-resolved polarization strategy retrieve intrinsic tensors HP, confirming pressure-induced enhancement. In situ HP synchrotron X-ray diffraction Raman scattering reveal strong correlation between [GeCl6] octahedral Optical absorption measurements show significant band gap closing compression, favoring First-principles calculations corroborate these findings. Our results offer tunable clean enhance halide establish reliable approach for probing pressure-dependent mechanism general.

Language: Английский

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Pressure-Driven Circularly Polarized Luminescence Enhancement and Chirality Amplification

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 11, 2025

Achieving ultrahigh-color-purity circularly polarized luminescence (CPL) in low-dimensional chiral perovskites is challenging due to strong electron–phonon coupling caused by lead halide octahedral distortion. Herein, the piezoluminescence behaviors of six novel perovskites, (S/R-3-XPEA)2PbBr4 (PEA = phenethylamine; X F, Cl, Br), were systematically investigated. Upon compression, (S/R-3-ClPEA)2PbBr4 exhibits significant piezofluorochromic behaviors, transforming from yellow CPL deep-blue CPL. At 2.5 GPa, intensity increases an order magnitude and its asymmetry factors (glum) are amplified initial ±0.03 ±0.1. (S/R-3-BrPEA)2PbBr4 presents a similar piezochromic response, realizing at 1.7 while (S/R-3-FPEA)2PbBr4 retains under high pressure. High-pressure structural characterization theoretical calculations confirm that pressure-enhanced halogen bonds reduce penetration depth S/R-3-BrPEA+ S/R-3-ClPEA+ into [PbBr6]4– frameworks, significantly suppressing increasing magnetic transition dipole moment (S/R-3-ClPEA)2PbBr4, which responsible for ultrahigh-purity chirality amplification, respectively.

Language: Английский

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Role of Host/Guest Coupling in Stabilizing the Phases of the Overtolerant Hybrid Perovskite MHyPbX₃

The Journal of Physical Chemistry C, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 2, 2025

Methylhydrazinium (MHy) lead halide, MHyPbBrxCl3–x, exhibits an interesting temperature-induced phase diagram transitioning from monoclinic (Phase-II) to orthorhombic (Phase-I) and eventually the disordered cubic at high temperatures. However, experimental observations indicate absence of or phases in compositions with x = 0 (chloride) 3 (bromide), respectively. We explain composition dependence transition sequence MHyPbX3 (X Cl, Br) perspective a host/guest framework for system. argue that transitions can be anticipated based on competition between host distortion coupling energies. A dominant MHyPbCl3 ensures stabilization intermediate Phase-I while pushing beyond its decomposition temperature. On other hand, balance energy scales MHyPbBr3 suppresses stabilizes phase. Our expectations were supported by first-principles-based estimates temperatures both compounds, which yielded trends agreement observations. Furthermore, ab initio molecular dynamics simulations revealed results disorder over locally structures, clear manifestation scales. propose same concept employed predict stable hybrid perovskites.

Language: Английский

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