Structural modification of hydroxyborates by adjusting the number of shared oxygen atoms and hydroxyl groups for further performance enhancement.

In recent years, hydroxyborates with excellent properties have attracted much attention. Through dedicated efforts, three new hydroxyborates-KBO(OH), CsBO(OH), and CsBO(OH)-have been successfully synthesized in a closed system. The ultraviolet (UV) cut-off edges of both KBO(OH) and CsBO(OH) are below 200 nm, indicating their potential as candidates for deep-ultraviolet (DUV) materials.

Exploiting Deep-Ultraviolet Nonlinear Optical Material RbScBOF Originated from Congruously Oriented [BO] Groups.

The exploration and research for deep-ultraviolet (UV) nonlinear optical (NLO) crystals are of great significance for all-solid-state lasers. This work is based on the excellent structural [BO] units which manipulate the excellent performances of famous commercial NLO crystal β-BaBO (β-BBO) to explore new alternatives of deep-UV NLO materials. A deep-UV rare-earth metal borate fluoride RbScBOF (RSBF) is successfully designed by combining the heterovalent ions substitution strategy, and fluorination strategy.

Extending Unique 1D Double-Chains to 2D Layers with Birefringent Gain by Introducing a Hydroxyl Group.

It remains a significant hurdle for discovering birefringent materials in the deep ultraviolet (DUV, λ < 200 nm). It is well-known that the OH anions are recognized for their capability to eliminate the dangling bonds from terminal oxygen atoms, promoting the ultraviolet (UV) cutoff edge blueshift and regulating the crystal structure. Here, two new barium hydroxyborates, BaBO(OH)(HO) (BaBOH) and NaBaBO(OH)(HO) (NaBaBOH), were designed and synthesized while displaying different dimensions.

A Sharp Improvement of Sulfate's Birefringence Induced by the Synergistic Effect of Heteroleptic and Dimeric Strategies.

As for tetrahedron-based ultraviolet nonlinear optical crystals, it is so difficult to achieve a sufficient birefringence to satisfy the phase-matching condition. Thereover, it is necessary to greatly increase the polarizability anisotropy of tetrahedra. Meanwhile, the tetrahedra should be arranged as uniformly as possible.

Mg assists in modulating the dimensionalities of the anionic frameworks of borates.

Three Mg-containing borates were obtained by high-temperature spontaneous crystallization. In the (AO)- or (AO-MO)-MgO-BO system (A is alkali metal and M is alkaline-earth metal) reported in the ICSD, LiMgSrBO is the first compound that contains one-dimensional infinite anionic chains, and the two examples of the isostructural AMgBO (A = Rb, Cs) exhibit a two-dimensional infinite bilayer structure for the first time, which contributes to the enrichment of the structural chemistry of Mg-containing borates. Besides, the results of comparison and analysis in this system clearly show that Mg not only affects the anionic frameworks of borates to produce low-dimensional structures but, together with the ratio of /, is responsible for the dimensionalities of the anionic frameworks in borates.

Rare-Earth Scandium Borate Fluoride with a Deep-Ultraviolet Cutoff Edge.

Through reasonable selections of raw materials and experimental methods, a new rare-earth borate fluoride KSc(BO)F is synthesized successfully by the high-temperature solution method in a closed system, which is the first noncentrosymmetric scandium borate fluoride. It crystallizes in the 2 space group of the orthorhombic crystal system and features an extremely complicated structure constructed by the fundamental building blocks [BO] units, Sc-based, and K-based polyhedra. To our knowledge, KSc(BO)F is the only rare-earth borate that contains two kinds of [BO] groups and crystallizes in the 2 space group, enriching the structural chemistry of rare-earth borates and rare-earth borate fluorides.

Introduction of the [B-O/F] Units Enhances the Band Gap and Birefringence from NaMgBOF to KNaBOF.

The borate family is the main source of deep-ultraviolet (DUV) birefringent crystals, and it has attracted a lot of attention due to versatile [B-O] basic units. Herein, two new borate-based compounds NaMgBOF and KNaBOF were discovered. Their fundamental building blocks are [BO] and [BOF] units, respectively.

Rational Design of the First Ammonium Magnesium Borate with Deep-Ultraviolet Cutoff Edge and Moderate Birefringence and Further Investigation into the Nature of Ammonium in the Borate System.

Through the rational design of the experimental method, the first combination of ammonium and magnesium in the borate system was successfully achieved. In this paper, a case of ammonium magnesium borate, (NH){Mg(HO)[BO(OH)]}·2HO, was successfully synthesized by a mild hydrothermal method at a relatively low temperature. A brief review was performed to show the participation of NH in the recent development of optical materials.

ABOF (A = NH, K): new members of ABOF family with deep-UV cutoff edges and moderate birefringence.

The fluorooxoborate ABOF family (A = alkali metal) has attracted much attention because of its diverse structures and properties. Herein, two new members of this family, (NH)BOF and KBOF, have been synthesized which exhibit different two-dimensional [BOF] layered structures. Millimeter-sized crystals of (NH)BOF have been grown with NHF as the flux.

Symmetry of antiferroelectric crystals crystallized in polar point groups.

Symmetry is an essential concept in physics, chemistry and materials science. Comprehensive, authoritative and accessible symmetry theory can provide a strong impetus for the development of related materials science. Through the sustained efforts of physicists and crystallographers, researchers have mastered the relationship between structural symmetry and ferroelectricity, which demands crystallization in the 10 polar point groups.

Enhanced mechanical quality factor of BiScO-PbTiO piezoelectric ceramics using glass composition.

Compared with pure Pb-based perovskite ferroelectric materials, Bi(Me)O-PbTiO (Me = Sc, In, Yb) have attracted attention due to their remarkable advantage in their Curie temperature. Among them, BiScO-PbTiO piezoelectric ceramic is a potential piezoelectric material in high-temperature applications for its high Curie temperature and excellent piezoelectric coefficient. However, its shortcomings are high dielectric loss and low mechanical quality factor.

Complete Sets of Material Constants of [001]-Poled 0.72Pb(MgNb)O 0.28PbTiO Single Crystals Using Alternating Current Poling.

Alternating current poling (ACP) is an effective method to improve the piezoelectric performance of relaxor-PbTiO3 (PT) ferroelectric single crystal. 0.72Pb(Mg1/3Nb2/3)O3-0.

Non-π-Conjugated Deep-Ultraviolet Nonlinear Optical Crystal KZn(SO)(HSO)F.

Deep-ultraviolet (deep-UV) (wavelengths of <200 nm) nonlinear optical (NLO) materials are playing an increasingly important role because of their significant technological applications in advanced scientific instruments. In recent years, the non-π-conjugated systems have received extensive attention as new emerging sources of deep-UV NLO materials. Here, a new non-π-conjugated deep-UV NLO material, KZn(SO)(HSO)F, has been successfully obtained by the hydrothermal method.

Giant Second-Harmonic Generation Response and Large Band Gap in the Partially Fluorinated Mid-Infrared Oxide RbTeMoOF.

Strong second-harmonic generation (SHG) and a wide band gap are two crucial but often conflicting parameters that must be optimized for practical nonlinear optical (NLO) materials. We report herein the first d-transition-metal (TM) tellurite with half of the d-TM-octahedra partially fluorinated, namely, quinary RbTeMoOF, which exhibits giant SHG responses (27 times that of KHPO (KDP) and 2.2 times that of KTiOPO (KTP) with 1064 and 2100 nm laser radiation, respectively), the largest SHG values among all reported metal tellurites.

Optimizing the Piezoelectric and Dielectric Properties of Pb(InNb)O₃-PbTiO₃ Ferroelectric Crystals via Alternating Current Poling Waveform.

The alternating current poling (ACP) method has been attracting significant attention because of the enhanced piezoelectric and dielectric properties of relaxor-based ferroelectric (FE) crystals with advantages of high-efficiency, time-savings, and ease of operation. The most commonly used poling waveform is the bipolar triangle. Other waveforms have been seldom applied in ACP.

π-Conjugated Trigonal Planar [C(NH)] Cationic Group: A Superior Functional Unit for Ultraviolet Nonlinear Optical Materials.

Employing π-conjugated anionic groups in molecular construction has been proven to be an effective strategy to find superior ultraviolet (UV) nonlinear optical (NLO) crystals over the decades. Herein, unlike the traditional π-conjugated anionic groups, we identify that a π-conjugated cationic group, viz., [C(NH)], is also an excellent UV NLO-active functional group in theory.

UV Solar-Blind-Region Phase-Matchable Optical Nonlinearity and Anisotropy in a π-Conjugated Cation-Containing Phosphate.

Wide ultraviolet (UV) transparency, strong second-harmonic generation (SHG) response, and sufficient optical birefringence for phase-matching (PM) at short SHG wavelengths are vital for practical UV nonlinear optical (NLO) materials. However, simultaneously optimizing these properties is a major challenge, particularly for metal phosphates. Herein, we report a non-traditional π-conjugated cation-based UV NLO phosphate [C(NH ) ] (PO ) ⋅3 H O (GPO) with a short UV cutoff edge.

Large Second-Harmonic Response and Giant Birefringence of CeF(SO) Induced by Highly Polarizable Polyhedra.

Second-harmonic generation (SHG) response and birefringence are two critically important properties of nonlinear optical (NLO) materials. However, the simultaneous optimization of these two key properties remains a major challenge because of their contrasting microstructure requirements. Herein, we report the first tetravalent rare-earth metal fluorinated sulfate, CeF(SO).

Broad bandwidth emission and in situ electric field modulation of photoluminescence in Nd-doped ferroelectric crystals.

The electric field modulation of photoluminescence in ferroelectric-optical materials as a novel in situ, non-damaging and real-time controllable method has drawn much research focus. The broad bandwidth emission of 33 nm and a tuneable luminescence contrast of 28% were achieved in Nd-doped Pb(MgNb)O-PbTiO (Nd:PMNT) tetragonal ferroelectric-optical crystals arising from spontaneous polarization. The study of Nd:PMNT ferroelectric crystals under a cyclic, triangular alternating current voltage wave showed that the change in the photoluminescence intensity subjected to an electric field is mainly related to the 180° domain distribution, rather than the 90° domain.

Giant Optical Anisotropy in the UV-Transparent 2D Nonlinear Optical Material Sc(IO ) (NO ).

Birefringence is a fundamental optical property for linear and nonlinear optical (NLO) materials. Thus far, it has proved to be very difficult to engineer large birefringence in optical crystals functioning in the UV region. Herein, we report the first 2D rare-earth iodate-nitrate crystal Sc(IO ) (NO ) (SINO), which is shown to exhibit giant optical anisotropy.

ZnBOCl: A New Deep-Ultraviolet Transparency Nonlinear Optical Crystal with Boracite Structure.

Nonlinear optical crystals play important roles in modern laser science and technology. However, the design and growth of new nonlinear optical (NLO) materials is still a challenging issue for researchers. Due to the excellent performance of MgBOCl crystal, we paid attention to the optimization of its structure, in order to find new NLO materials with favorable properties.

A(HCNO)(NO) (A = K, Rb): Alkali-Metal Nitrate Isocyanurates with Strong Optical Anisotropy.

The first alkali-metal nitrate isocyanurates, A(HCNO)(NO) (A = K, Rb), were synthesized by the tactic of introducing (NO) into isocyanurate with a mild hydrothermal technique. They crystallized into the same monoclinic centrosymmetric (CS) space group 2/, which featured a 2D [(HCNO)(NO)] layered structure separated by K and Rb cations, respectively. Both compounds exhibited short ultraviolet cutoff edges (λ = 228 and 229 nm) and large birefringences (Δ = 0.

Enhanced Energy Storage Density of Lead Lutetium Niobate Crystals by Electric Field-Induced Secondary Phase Transition Na/La Codoping.

As emerging materials for capacitor applications, antiferroelectric (AFE) materials possess high energy storage density. AFE single crystals are conducive to studying the physical mechanism of AFE response. However, the preparation of AFE single crystals is a huge and long-standing challenge.