Computer-Aided Development of New Nonlinear Optical Materials.

Exploring new nonlinear optical (NLO) materials is an urgent need for advanced photoelectric technologies. However, the discovery of new materials with targeted properties is time-consuming, and involves various challenges by the traditional trial-and-error experiments. Recently, the theoretical prediction-guided structural design has been demonstrated as a feasible way for efficiently developing new NLO materials, and a large number of NLO candidates with excellent optical properties have been explored.

Tunable Optical Anisotropy in Rare-Earth Borates with Flexible [BO] Clusters.

Borates have garnered a lot of attention in the realm of solid-state chemistry due to their remarkable characteristics, in which the synthesis of borates with isolated [BO] by adding rare-earth elements is one of the main areas of structural design study. Five new mixed-metal Y-based rare-earth borates, BaZnY(BO), KNaY(BO), LiCsY(BO), LiRbY(BO), and RbCaY(BO), have been discovered using the high-temperature solution approach. Isolated [BO] clusters arranged in various configurations comprise their entire anionic framework, allowing for optical anisotropy tuning between 0.

Where do the Fluorine Atoms Go in Inorganic-Oxide Fluorinations? A Fluorooxoborate Illustration under Terahertz Light.

The substitution of fluorine atoms for oxygen atoms/hydroxyl groups has emerged as a promising strategy to enhance the physical and chemical properties of oxides/hydroxides in fluorine chemistry. However, distinguishing fluorine from oxygen/hydroxyl in the reaction products poses a significant challenge in existing characterization methods. In this study, we illustrate that terahertz (THz) spectroscopy provides a powerful tool for addressing this challenge.

Fluorination Strategy Towards Symmetry Breaking of Boron-centered Tetrahedron for Poly-fluorinated Optical Crystals.

Borate crystals can be chemically and functionally modified by the fluorination strategy, which encourages the identification of emerging fluorooxoborates with a structure and set of characteristics not seen in any other oxide parents. However, the bulk of fluorooxoborates have been found accidentally, rational methods of synthesis are required, particularly for the infrequently occurring poly-fluorinated components. Herein, we reported the use of bifluoride salts as a potent source of fluorine to prepare fluorooxoborates that contain rarely tri-fluorinated [BF X] (X=O and CH ) tetrahedra and eleven compounds were found.

Breaking the Inherent Interarrangement of [BO] Clusters for Nonlinear Optics with Orbital Hybridization Enhancement.

The [BO] group as a prime functional unit provides borates with intrinsic properties that are modified by coordination to cations. Inherent [BO] cluster structures in borates exclusively made of them have a near-plane configuration, with more than 90% of them having a maximum dihedral angle of zero and the remaining ones being less than 13°. Although such an inherent configuration can produce considerable birefringence for good phase-matching ability, this is not conducive to obtaining high conversion efficiency and beam quality due to the walk-off effects in the nonlinear optical process.

Hydroxyfluorooxoborate (NH)[C(NH)][BOF(OH)] for exploring the effects of cation substitution on structure and optical properties.

Cation substitution is a straightforward but effective technique for improving the structure and properties; however, controlling directed substitution still poses significant difficulties. Herein, a metal-free hydroxyfluorooxoborate (NH)[C(NH)][BOF(OH)] has been synthesized using the strategy of heterologous substitution based on the template of A[BOF(OH)]. Tunable structure and optical properties have been achieved varied A-site cation substitution.

Heterologous Isomorphic Substitution Induces Optical Property Enhancement for Deep-UV Crystals: a Case in Rb[BOF(OH)].

Optical anisotropy is pivotal for optical crystals, and it can be characterized by the maximum algebraic difference in refractive indices. Improving the optical anisotropy, especially for deep-ultraviolet (UV) crystals, is still a challenge and of interest. Herein, a new hydroxyfluorooxoborate, Rb[BOF(OH)], was obtained by the heterologous isomorphic substitution strategy.

Zn HgP S : A Wide Bandgap Hg-Based Infrared Nonlinear Optical Material with Large Second-Harmonic Generation Response.

Hg-based chalcogenides, as good candidates for the exploration of high-performance infrared (IR) nonlinear optical (NLO) materials, usually exhibit strong NLO effects, but narrow bandgaps. Herein, an unprecedented wide bandgap Hg-based IR NLO material Zn HgP S (ZHPS) with diamond-like structure is rationally designed and fabricated by a tetrahedron re-organization strategy with the aid of structure and property predictions. ZHPS exhibits a wide bandgap of 3.

BaMoO Polymorphs with Tunable Symmetries and Properties.

Polymorphism is a well-known but important phenomenon in the field of solid-state chemistry. Crystalline materials can form various polymorphs and present drastically varied physical and chemical properties. Herein, systematic exploration of the BaO-MoO binary system leads to the discovery of a new barium molybdate, α-BaMoO.

Cs[BOF(OH)]: discovery of a hydroxyfluorooxoborate guided by selective organic-inorganic transformation.

Selective transformation between organic and inorganic systems is crucial but still remains a challenge. Herein, we demonstrated that selective organic-inorganic transformation is a simple but effective strategy to find new hydroxyfluorooxoborates. By replacing the [PhP]/[PhMeP] organic cations with Cs atoms, a new hydroxyfluorooxoborate Cs[BOF(OH)] with three-membered [BOF(OH)] clusters was synthesized.

Finding a Deep-UV Borate BaZnB O with Edge-sharing [BO ] Tetrahedra and Strong Optical Anisotropy.

The polarization modulation of deep-UV light is an important process that incorporates functionality to selectively respond to light-mater interaction. Typically, optical anisotropy is foremost to the use efficiency of deep-UV birefringent crystals. Herein, a new congruently melting polyborate with extremely large birefringence (Δn =0.

(NH)BPOF: a deep-UV nonlinear optical crystal with unique [BPOF] layers.

Deep-ultraviolet (DUV) nonlinear optical (NLO) crystals that can extend the output range of coherent light below 200 nm are pivotal materials for solid-state lasers. To date, KBeBOF (KBBF) is the only usable crystal that can generate DUV coherent light by direct second harmonic generation (SHG), but the layered growth habit and toxic ingredients limit its application. Herein, we report a new fluoroborophosphate, (NH)BPOF (ABPF), containing four different functional units: [BO], [BO], [BOF] and [PO].

Rearrangement of [BO] Dimers within [BO] Clusters Enables Enhanced Optical Anisotropy in LiCsAlBOF.

Borates with tunable structure and property currently provide a new rich source for solid-state chemistry and materials science. Realization of property improvement via simple structural regulation is a rising hot spot of borate-based research. Herein, a new aluminoborate fluoride, LiCsAlBOF, with [BO] clusters was discovered, and it was found to melt congruently.

Double-Modification Oriented Design of a Deep-UV Birefringent Crystal Functionalized by [B O F (OH) ] Clusters.

Polarization modulation of deep-UV light is of significance to current technologies, and to this end, the birefringent crystal has emerged as an invaluable material as it allows for effective light modulation. Herein, a double-modification strategy driven by F and OH anions that makes double effects towards the critical property enhancement of deep-UV birefringent crystals is proposed. This leads to a new hydroxyborate (NH ) [B O F (OH) ] with giant cluster as a deep-UV birefringent crystal with large birefringence (Δn =0.

(NH)[HPOF]: maximizing the optical anisotropy of deep-ultraviolet fluorophosphates.

Although phosphates are a rich source of deep-ultraviolet optical materials, the realization of large optical anisotropy in them still remains a challenge because of the small polarizability anisotropy of [PO] units. Inspired by the fluoridation strategy and hydrogen bond interaction, a new metal-free monofluorophosphate, (NH)[HPOF], was synthesized, which exhibits a large birefringence (cal. 0.

Strong Nonlinearity Induced by Coaxial Alignment of Polar Chain and Dense [BO ] Units in CaZn (BO ).

Discovery of new efficient nonlinear optical (NLO) materials with large second-order nonlinearity for the short-wave ultraviolet spectral region (λ ≤266 nm, PM=phase-matching) is still very challenging. Herein, a new beryllium-free borate CaZn (BO ) with Sr Be B O (SBBO) double-layered like configuration was rationally designed, which not only preserves the structural merits but also eliminates the limitations of the SBBO crystal. CaZn (BO ) shows a large PM second harmonic generation (SHG) reponse of 3.

Identical in Formula but Not Isotypic in Configuration: Discovery of a New Highly Polymerized [BO] Cluster in CsAlBO.

The discovery of new borates with unique structures has always been a growing part of solid-state chemistry, especially for polyborates. Herein, a new aluminoborate, CsAlBO, has been discovered by a high-temperature solution in a vacuum system. The highly polymerized [BO] cluster, unlike the annular configuration in previously reported polyborates, is found in CsAlBO for the first time.

BaZn(BO)F: a new beryllium-free zincoborate with a KBBF-type structure.

A new beryllium-free zincoborate, BaZn(BO)F, with a KBBF-type structure has been synthesized for the first time. The electrostatic force of interaction in BaZn(BO)F provides better linkage in neighboring [ZnBOF] single layers. BaZn(BO)F is the first case of borates with both [ZnOF] tetrahedra and [ZnO] octahedra, enriching the structural chemistry of borate system.

Tetrafluoroborate-Monofluorophosphate (NH)[POF][BF]: First Member of Oxyfluoride with B-F and P-F Bonds.

Inspired by the strategy of fluorine introduction in borates and phosphates, the inorganic oxyfluoride (NH)[POF][BF] with B-F and P-F bonds has been characterized as the first fluoroborate-fluorophosphate. The International Union of Pure and Applied Chemistry (IUPAC) name for (NH)[POF][BF] should be ammonium tetrafluoroborate-monofluorophosphate according to the structure characteristics. The existence and coordination of fluorine in (NH)[POF][BF] were confirmed by several approaches, including single-crystal structure analysis; bond valence analysis; and X-ray energy dispersive, infrared spectrum, and also nuclear magnetic resonance spectroscopy.

Hydroxyfluorooxoborate Na[B O F (OH) ]⋅[B(OH) ]: Optimizing the Optical Anisotropy with Heteroanionic Units for Deep Ultraviolet Birefringent Crystals.

Maximizing the optical anisotropy in birefringent materials has emerged as an efficient route for modulating the polarization-dependent light propagation. Currently, the generation of deep-ultraviolet (deep-UV) polarized light below 200 nm is essential but challenging due to the interdisciplinary significance and insufficiency of high-performing birefringent crystals. Herein, by introducing multiple heteroanionic units, the first sodium difluorodihydroxytriborate-boric acid Na[B O F (OH) ]⋅[B(OH) ] has been characterized as a novel deep-UV birefringent crystal.

Expanding the chemistry of borates with functional [BO] anions.

More than 3900 crystalline borates, including borate minerals and synthetic inorganic borates, in addition to a wealth of industrially-important boron-containing glasses, have been discovered and characterized. Of these compounds, 99.9 % contain only the traditional triangular BO and tetrahedral BO units, which polymerize into superstructural motifs.

Cs B O F : First Fluorooxoborate with [BF ] Involving Heteroanionic Units and Extremely Low Melting Point.

Herein, a new congruently melting mixed-anion compound Cs B O F has been characterized as the first fluorooxoborate with [BF ] involving heteroanionic units. Compound Cs B O F possesses two highly fluorinated anionic clusters and therefore its formula can be expressed as Cs (B O F ) ⋅ Cs(BF ). The influence of [BF ] units on micro-symmetry and structural evolution was discussed based on the parent compound.

RbMT (BO ) O (M=Ba, Sr; T=Al, Ga): New Double-Layered Oxyborates Constructed from [BO ] Triangles and [TO ] Tetrahedra.

Four new alumino-/galloborates RbMT (BO ) O (M=Ba, Sr; T=Al, Ga) have been synthesized for the first time by using a high-temperature solution method. All the title compounds have Sr Be B O -like structures, in which the [BO ] triangles and [TO ] tetrahedra form the final double-layered configurations with the M- and Rb-site atoms located between and in the double layer, respectively. The structure evolution from Sr Be B O to RbMT (BO ) O series is discussed.