A HTO-Type Nonlinear Optical Fluorophosphate with Ultrawide Bandgap.

Compounds having hexagonal tungsten oxides (HTO) topology are of intense research interests owing to their potential functional properties, such as nonlinear optical (NLO) performances. However, most of the reported HTO-type compounds exhibit narrow optical bandgaps because of the d-d electronic transition of compositional d transition metals and lone pair electrons effect of Se/Te, which hinder their applications in the high-energy field, such as deep-ultraviolet (deep-UV) region. In this work, a new fluorophosphate, (NH)[ScF(PO)](POF) exhibiting HTO-topological structures is reported.

Designing a 2D van der Waals oxide with lone-pair electrons as chemical scissor.

Two-dimensional (2D) van der Waals (vdW) materials are known for their intriguing physical properties, but their rational design and synthesis remain a great challenge for chemists. In this work, we successfully synthesized a new non-centrosymmetric oxide, i.e.

A highly birefringent metal-free crystal assembled by cooperative non-covalent interactions.

Birefringent crystals can manipulate the phase and polarization of light, so they are widely used as essential components in various optical devices. Common strategies to construct birefringent crystals are introducing metal cations that are either able to realize favorable coordination with functional anionic units or are susceptible to polarizability anisotropy. Herein, we report a metal-free crystal, NH(HCNO)·2HO, synthesized using the facile solution method.

Deep-Ultraviolet Bialkali-Rare Earth Metal Anhydrous Sulfate Birefringent Crystal.

Birefringence is an important linear optical property of anisotropic crystals that plays a significant role in regulating light polarization. A new bialkali-rare earth metal sulfate, NaRbY(SO) compound, consisting of non-π-conjugated alkali metals and rare earth metal-centered dodecahedral YO has been synthesized. The structure analysis suggests that the three-dimensional (3D) structure of the compound is found to be attributable to the combination of dodecahedral YO and tetrahedral SO groups with Na and Rb located in the cavities.

CHNBrX (X = Cl, Br, NO): Three Excellent Birefringent Crystals with Distinct Optical Anisotropy Regulated by Anions.

A large optical anisotropy is the most important parameter of birefringent crystals. Integrating π-conjugated groups with large polarizable anisotropy into target compounds is a common strategy for constructing brilliant birefringent crystals. However, the key problem is to enhance the density of the birefringence-active units and further arrange them parallelly.

Combining rigid and deformable groups to construct a robust birefringent crystal for compact polarization components.

There is a pressing demand for the development of novel birefringent crystals tailored for compact optical components, especially for crystals exhibiting large birefringence across a range of temperatures. This has commonly been achieved by introducing various deformable groups with high polarizability anisotropy. In this study, we combined both rigid and deformable groups to synthesise a new birefringent crystal, AlTeMoO, which demonstrates an exceptional birefringence value of 0.

Van der Waals quaternary oxides for tunable low-loss anisotropic polaritonics.

The discovery of ultraconfined polaritons with extreme anisotropy in a number of van der Waals (vdW) materials has unlocked new prospects for nanophotonic and optoelectronic applications. However, the range of suitable materials for specific applications remains limited. Here we introduce tellurite molybdenum quaternary oxides-which possess non-centrosymmetric crystal structures and extraordinary nonlinear optical properties-as a highly promising vdW family of materials for tunable low-loss anisotropic polaritonics.

Designing a Hybrid Perovskite with Enlarged Birefringence and Bandgap for Modulation of Light Polarization.

Birefringent crystals have important applications in optoelectronics areas due to their ability to modulate and polarize light. Despite increasing discovery of the birefringence potential of new crystals, it remains a great challenge to optimize both birefringence and bandgap simultaneously. Herein, a 1D chain-like hybrid perovskite birefringent crystal designed by 3D-to-1D dimensional tailoring, (GAM) PbI ·H O (GAM = C N H ), is presented, showing enlarged birefringence of 0.

A Two-Dimensional Hybrid Perovskite With Heat Switching Birefringence.

Birefringent crystals that can switch light polarization have important applications in optoelectronics. In the last decades, birefringence is mostly optimized by chemical strategies. Recently, switching birefringence by physical means has attracted much attention.

A Non-π-Conjugated Molecular Crystal with Balanced Second-Harmonic Generation, Bandgap, and Birefringence.

Traditional nonlinear optical (NLO) crystals are exclusively limited to ionic crystals with π-conjugated groups and it is a great challenge to achieve a subtle balance between second-harmonic generation, bandgap, and birefringence for them, especially in the deep-UV spectrum region (E  > 6.20 eV). Herein, a non-π-conjugated molecular crystal, NH BH , which realizes such balance with a large second-harmonic generation response (2.

Designing a Dimension Reduced Hybrid Perovskite with Robust Large Birefringence by Expanding Cationic π-Delocation.

It is in great demand to discover new materials with large birefringence for the miniaturization of optical communication devices. In this work, a new one-dimensional hybrid halide perovskite, (C N H )Pb Br , is obtained successfully through structural design of dimension reduction from the notable three-dimensional halide perovskite CsPbBr . Remarkably, (C N H )Pb Br exhibits a significantly enhanced birefringence of ∆n = 0.

Mixed Alkali Metal and Alkaline Earth Metal Scandium Borate Birefringence Material with Layered Structure and Short Ultraviolet Cutoff Edge.

Birefringent crystals are essential in the domains of linear and nonlinear optics that need light wave polarization control. Rare earth borate has become a popular study material for ultraviolet (UV) birefringence crystals due to its short cutoff edge in the UV area. RbBaScBO, a two-dimensional layered structure compound with the BO group, was effectively synthesized through spontaneous crystallization.

A Hydrogen Bonded Supramolecular Framework Birefringent Crystal.

Birefringent crystals could modulate the polarization of light and are widely used as polarizers, waveplates, optical isolators, etc. To date, commercial birefringent crystals have been exclusively limited to purely inorganic compounds such as α-BaB O with birefringence of about 0.12.

CHNOCd(NO)·2HO: a birefringent crystal with an enlarged band-gap derived from covalent edge-sharing connection.

A new birefringent crystal, CHNOCd(NO)·2HO, was designed by combining a π-conjugated [CHNO] group with a CdON polyhedron. Notably, the experimental energy gap is 0.02 eV higher than that of the organic raw material, which resulted from a covalent edge-sharing connection, implying a new strategy to improve the band-gap of birefringent materials.

A Second-Order Nonlinear Optical Material Consisting of Two π-Conjugated Groups.

This work reports a new second-order nonlinear optical (NLO) material [C(NH ) ] C N S (GU TMT), consisting of π-conjugated planar (C N S ) and triangular [C(NH ) ] groups. Interestingly, GU TMT exhibits a large NLO response (2.0×KH PO ) and moderate birefringence 0.

BaPbBe(BO)F: The First Pb-Containing Beryllium Borate Fluoride with Trigonal Prismatic PbO and 2D [BeBOF] Layers.

BaPbBe(BO)F (BPBBF), a previously unreported lead-containing beryllium borate fluoride, has been successfully grown through a high-temperature flux method. Its structure is solved by single-crystal X-ray diffraction (SC-XRD), and it is optically characterized via infrared, Raman, UV-vis-IR transmission, and polarizing spectra as well. SC-XRD data suggests that it can be indexed by a trigonal unit cell (space group 31) with lattice parameters = 4.

Local Polarity-Induced Assembly of Second-Order Nonlinear Optical Materials.

ConspectusSecond-order nonlinear optical (NLO) materials, producing coherent light by the cascaded frequency conversion, are current hot topics in material chemistry and optics, as they play an important role in diverse fields, such as laser technology, precision measurements, and quantum information as well as future space propulsion. The prerequisite for a second-order NLO material is that it must crystallize in a noncentrosymmetric space group, but it tends to be centrosymmetric in terms of thermodynamical stability. Furthermore, it should simultaneously satisfy strict requirements on second-order NLO coefficients, birefringence, optical transmittance windows, crystal growth, and so on.

Bio-Inspired Synthetic Hydrogen-Bonded Organic Frameworks for Efficient Proton Conduction.

Hydrogen-bonded organic frameworks (HOFs) are a rising class of promising proton-conducting materials. However, they always suffer from the inherent contradiction between chemical stability and proton conduction. Herein, inspired by the self-assembly of lipid bilayer membranes, a series of aminomethylphosphonic acid-derived single-component HOFs are successfully developed with different substituents attached to the phosphonate oxygen group.

A High-Performance Nonlinear Optical Crystal with a Building Block Containing Expanded π-Delocalization.

Common nonlinear optical (NLO) crystals consist of traditional functional building blocks with inherent optical limitation. Herein, inspired by traditional (B O ) inorganic building block, we theoretically identified a new type of organic functional building blocks and then successfully synthesized the first cyamelurate NLO crystal, Ba(H C N O )  ⋅ 8 H O. To our surprise, the constituent (H C N O ) building block is not in structurally optimal arrangement, but Ba(H C N O )  ⋅ 8 H O exhibits excellent optical properties including wide band gap of 4.

A Hybrid Antiperovskite with Strong Linear and Second-Order Nonlinear Optical Responses.

Antiperovskites have been studied since the 1980s because of their rich physical and chemical properties, but their linear and second-order nonlinear optical responses remain largely unknown. Here we report a new polar crystal, Cs Cl(HC N S ) (I), which features a quasi-one-dimensional antiperovskite structure composed of ClCs polyhedra and A-site [HC N S ] rings. To our best knowledge, this kind of antiperovskite structure is reported for the first time.

An Optically Anisotropic Crystal with Large Birefringence Arising from Cooperative π Orbitals.

Birefringent materials are highly demanded for high-performance polarized optics. As compared with artificial anisotropic metamaterials, anisotropic crystals have advantages of low optical losses and easy processing, but their birefringence is still limited. Herein, based on first-principles studies, we identified a new type of functional anion units, (H C N ) (x=0, 1, 2), and then successfully synthesized a new anisotropic crystal, namely, CsH C N ⋅H O (I), whose crystal structure consists of (H C N ) anions.

Maximizing the linear and nonlinear optical responses of alkaline tricyanomelaminate.

High-performance bi-functional materials are in urgent demand for the next-generation integrated optical devices. In this work, we successfully synthesized the first tricyanomelaminate with bi-functional optical responses, namely CsCN•HO (), from its analogue NaCN•3HO by a facile ion exchange method. In contrast to NaCN•3HO, realizes an optimal arrangement of -conjugated (CN) anion groups in its crystal structure.

A Hybrid Halide Perovskite Birefringent Crystal.

Birefringent crystals that can modulate the polarization of light play a significant role in modern optical devices including polarizing microscopes, optical isolators, and achromatic quarter-wave plates. To date, commercial birefringent crystals are exclusively limited to purely inorganic compounds. Here we report a new organic-inorganic hybrid halide, MLAPbBr (MLA=melamine), which features a (110)-oriented layered perovskite structure.

CsY(SO)·4HO: A Deep-Ultraviolet Birefringent Crystal Induced by an Edge-Sharing Connection.

SO tetrahedral groups have weak polarization anisotropy, which thus results in the small birefringence of sulfates. Here, we report new sulfate CsY(SO)·4HO with unprecedented birefringence among deep-ultraviolet (deep-UV) sulfates. Its single crystal (10 mm × 3.