Spatially Correlated Chirality in Chiral Two-Dimensional Perovskites Revealed by Second-Harmonic-Generation Circular Dichroism Microscopy

Nano Letters, Год журнала: 2023, Номер 23(16), С. 7434 - 7441

Опубликована: Авг. 8, 2023

Understanding the chiral mechanism of hybrid perovskites is a prerequisite for developing relevant chiroptoelectronic applications. Although conventional circular dichroism (CD) spectroscopy can be used to characterize chirality in perovskites, it has low signal-to-noise ratio and provide only information about macroscopic chirality. Herein, with aim revealing microscopic we utilize spacer cation alloying strategy construct two-dimensional perovskites. For first time, demonstrate second-harmonic-generation CD microarea imaging perovskite thin films unveil their spatially correlated In combination theoretical calculations, revealed that caused by localized out-of-plane supramolecular orientations. This work will not advance understanding chiroptical activity but also inspiration rational design synthesis chirality-related nonlinear optoelectronic devices.

Язык: Английский

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Chiral Hybrid Perovskites (R-/S-CLPEA)₄Bi₂I₁₀ with Enhanced Chirality and Spin–Orbit Coupling Splitting for Strong Nonlinear Optical Circular Dichroism and Spin Selectivity Effects

Chemistry of Materials, Год журнала: 2023, Номер 35(11), С. 4347 - 4354

Опубликована: Июнь 2, 2023

Chiral hybrid halide perovskites have attracted considerable attention in optoelectronics and spintronics owing to their unique optical, electric, spin–orbit coupling (SOC) properties. In this article, with focus on the design scheme increase nonlinear optical (NLO) circular dichroism (CD) spin selectivity effects by assembling chlorine-modified chiral R-/S-CLPEA [CLPEA = 1-(4-chlorophenyl)ethylamine] into bismuth-based perovskites, a pair of (R-/S-CLPEA)4Bi2I10 were synthesized characterized experimentally. A large NLO CD effect strong spin-dependent charge transport confirmed experimental measurements. The chirality-induced textures illustrated SOC band structures from first-principles simulations. combined theoretical results demonstrate that it is synergic chirality CLPEA Bi2I10 dimer endows these textures, effect, remarkable properties, which are importance for functional optics spintronics.

Язык: Английский

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Strong chiroptical nonlinearity in coherently stacked boron nitride nanotubes

Nature Nanotechnology, Год журнала: 2024, Номер unknown

Опубликована: Июнь 6, 2024

Язык: Английский

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Mechanical Twisting-Induced Enhancement of Second-Order Optical Nonlinearity in a Flexible Molecular Crystal

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 7, 2025

Flexible molecular crystals are essential for advancing smart materials, providing unique functionality and adaptability applications in next-generation electronics, pharmaceuticals, energy storage. However, the optical of flexible have been largely restricted to linear optics, with nonlinear (NLO) properties rarely explored. Herein, we report on application mechanical twisting second-order optics. The crystal formed through self-assembly model compound 9-anthraldehyde (AA) features an intrinsic chiral noncentrosymmetric structure, demonstrating high efficiency second harmonic generation (SHG) NLO circular dichroism, which could be greatly enhanced by macroscopic twisting. anisotropic stacking imparts AA flexibility combined elastic bending plastic isochiral enhance SHG intensities order magnitude depending their M- or P-configuration. Meanwhile, dichroism factor gSHG-CD twisted is increased, achieving highest reported anisotropy among organic materials. These boosted performances intensity chiroptical response expected expand photonic crystals.

Язык: Английский

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Optical Second Harmonic Generation of Low-Dimensional Semiconductor Materials

Nanomaterials, Год журнала: 2024, Номер 14(8), С. 662 - 662

Опубликована: Апрель 11, 2024

In recent years, the phenomenon of optical second harmonic generation (SHG) has attracted significant attention as a pivotal nonlinear effect in research. Notably, low-dimensional materials (LDMs), SHG detection become an instrumental tool for elucidating properties due to their pronounced second-order susceptibility and distinct electronic structure. This review offers exhaustive overview process experimental configurations such materials. It underscores latest advancements harnessing sensitive probe investigating attributes these materials, with particular focus on its role unveiling structures, bandgap characteristics, crystal symmetry. By analyzing signals, researchers can glean invaluable insights into microscopic Furthermore, this paper delves applications imaging time-resolved experiments. Finally, future directions challenges toward improvement NLO LDMs are discussed provide outlook rapidly developing field, offering crucial perspectives design optimization pertinent devices.

Язык: Английский

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Enhanced Second-Harmonic Generation in Thin-Film Lithium Niobate Circular Bragg Nanocavity

Nano Letters, Год журнала: 2024, Номер 24(37), С. 11676 - 11682

Опубликована: Сен. 3, 2024

Second-order nonlinearity gives rise to many distinctive physical phenomena, e.g., second-harmonic generation, which play an important role in fundamental science and various applications. Lithium niobate, one of the most widely used nonlinear crystals, exhibits strong second-order effects electro-optic properties. However, its moderate refractive index etching sidewall angle limit capability confining light into nanoscales, thereby restricting application nanophotonics. Here, we exploit nanocavities formed by circular Bragg gratings, support resonant anapole modes, achieve a 42 000-fold enhanced generation thin-film lithium niobate. The nanocavity record-high normalized conversion efficiency 1.21 × 10

Язык: Английский

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Lead-Free Chiral Perovskite for High Degree of Circularly Polarized Light Emission and Spin Injection

Nano Letters, Год журнала: 2024, Номер 24(3), С. 1001 - 1008

Опубликована: Янв. 10, 2024

We report a zero-dimensional (0D) lead-free chiral perovskite (S-/R-MBA)4Bi2I10 with high degree of circularly polarized light (CPL) emission. Our 0D exhibits an average circular polarization (DOCP) 19.8% at 78 K under linearly laser excitation, and the maximum DOCP can reach 25.8%, which is 40 times higher than highest 0.5% in all reported perovskites to best our knowledge. The attributed free exciton emission Huang–Rhys factor 2.8. In contrast, prior reports are dominant by self-trapped spin relaxation reduces dramatically. Moreover, we realize manipulation valley freedom monolayer WSe2 using injection perovskites. results provide new perspective develop devices for CPL source, spintronics, valleytronics.

Язык: Английский

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Chiral quasi-bound states in the continuum for refractive-index sensing in metasurfaces

Physical Review Applied, Год журнала: 2024, Номер 22(4)

Опубликована: Окт. 15, 2024

Язык: Английский

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Layered and Low-Dimensional Lead, Silver, and Bismuth Halide Perovskites Directed by Halogen-Substituted Spacer Cations

Chemistry of Materials, Год журнала: 2024, Номер 36(21), С. 10605 - 10615

Опубликована: Окт. 19, 2024

Hybrid organic–inorganic metal halides provide a diverse parameter space in which the optoelectronic properties can be tuned through composition. The compositional tunability extends to site, expanded from single valent metals (e.g., Pb2+) multivalent Ag+ and Bi3+), dimension (2D, 1D, or 0D). However, deeper understanding of how organic cations template these halide structures is needed. Here, we synthesize study series new layered low-dimensional (Pb, Ag, Bi) templated by halogenated aryl spacer 2-chlorobenzylammonium (2ClBZ) 3-chloro-2-fluorobenzylammonium (3Cl2FBZ). We report lead perovskites, (3Cl2FBZ)2PbBr4, (2ClBZ)3PbI5, (3Cl2FBZ)2PbI4, compare them their silver and/or bismuth analogs (2ClBZ)4AgBiBr8, (3Cl2FBZ)4AgBiBr8, (2ClBZ)3Bi2I9, (3Cl2FBZ)4Bi2I10. In all structures, halogen-substituted result 2D "pseudo-2D" layering, but different halogen substituents introduce distortions (tilting, octahedral distortion) dimensional reduction 1D 0D depending on compositions. Optical absorption measurements reveal bandgaps are tunable sites, dimension, extents. Furthermore, (3Cl2FBZ)4Bi2I10 crystallizes noncentrosymmetric group Cmc21 exhibits second-harmonic generation (SHG). interactions resultant structural examined here insights toward engineering noncentrosymmetry control hybrid perovskites.

Язык: Английский

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Switchable planar chirality and spin texture in highly ordered ferroelectric hybrid perovskite domains

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Ноя. 25, 2024

Chiral organic-inorganic hybrid perovskites offer a promising platform for developing non-linear chiro-optical applications and chiral-induced spin selectivity. Here, we show that achiral have highly ordered ferroelectric domains with orthogonal polarization exhibit planar chirality, as manifested by second harmonic generation strong circular dichroism. Interestingly, the handedness of dichroism response can be alternatingly switched between orthogonally polarized domain walls. To correlate origin chirality in these domains, atom-resolved atomic force microscopy is used to reveal distinct arrangements rows crystals indicate symmetry breaking. Remarkably, large SHG anisotropy factor 0.41 measured at wall. Additionally, spatially resolved two-photon photoluminescence excitation measurement provide evidence larger Rashba spin-splitting chiral compared domain-free areas. Our discoveries domain-dependent texture hold great promise advancement domain-specific applications.

Язык: Английский

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