Polar-Layer-Driven Reconstruction of a Noncentrosymmetric Vandate Mid-Infrared Nonlinear-Optical Crystal.

Noncentrosymmetry (NCS) is essential for a second-harmonic nonlinear-optical (NLO) crystal; however, the tailored synthesis of NCS materials has historically posed significant challenges because the adjacent dipole moments of constituted NLO-active units in the structure tend to align in opposite directions, resulting in the NLO effect being canceled as in a centrosymmetric (CS) crystal. In this work, we propose a polar-layer-driven strategy, wherein a polarization-layered framework is constructed to constrain the dipole moment to align in the same direction, thereby facilitating the formation of the NCS structure. Taking the layered structure CS KZnVO as a prototype compound, a novel vandate KZnVOBr (KZVB) was rationally synthesized via a multiple sites-oriented cosubstition method.

Antithermal-Quenching All-Inorganic Perovskite Crystals with Green Ultralong Persistent Luminescence for Advanced Anticounterfeiting Applications.

Long persistent luminescence (PersL) materials have revolutionized many fields of optoelectronics and photonics due to their applications in anticounterfeiting, information encryption, and in vivo bioimaging. Here, we reported a novel PersL crystal prepared by the heterovalent doping of Sb into perovskite tetragonal phase RbCdCl, comparing with the pristine non-perovskite orthorhombic phase analogue without PersL property. Surprisingly, under the UV light irradiation, the title crystals concurrently exhibit green ultralong PersL (>2400 s), high photoluminescence quantum yield (49.

RE(HSeO)(SeO)(HO)·(HO) (RE = Y, Gd): Two Rare-Earth Selenite Nonlinear Optical Crystals with Wide Band Gaps.

The band gap is one of the significant parameters for nonlinear optical (NLO) materials, which is the key factor in their application band in laser technology. This study reports the synthesis of two rare-earth selenite NLO crystals, namely, RE(HSeO)(SeO)(HO)·(HO) (RE = Y, Gd), utilizing the hydrothermal technique. The two compounds are isostructural, and both belong to the orthorhombic chiral space group of 222 and possess three-dimensional structures consisting of two-dimensional rare-earth selenite layers connected by hydrogen bonds (O-H··O).

CHNCO·2HO and NaCO·3HO: Two Ultraviolet Birefringent Compounds with the [CO] Group.

In modern optics, birefringent materials that can manipulate light polarization play important roles in lasers and information fields. The search for ultraviolet (UV) crystals with large birefringence is the focus of attention in the field of optical materials. In this work, we synthesized two birefringent crystals, CHNCO·2HO and NaCO·3HO, containing planar π-conjugated [CO] groups.

KHgGeSe: A Quaternary Hg-Based Selenide with Nonlinear Optical Properties.

A new quaternary Hg-based selenide KHgGeSe was successfully synthesized and characterized as an engaging infrared (IR) nonlinear optical (NLO) material, which crystallizes in the 2 space group of the noncentrosymmetric monoclinic crystal system. The crystal structure of KHgGeSe is characterized by the stacking of countless layers with K cations filling the interlayers. The UV-vis-NIR diffuse reflectance spectrum shows that KHgGeSe possesses an indirect band gap of 2.

Polymorphism of Niobium Phosphate Bronze NaNbPO Deduced by the Packings of Structural Units: A Centrosymmetric Phase.

Herein, a new centrosymmetric phase NaNbPO (referred to as CS-NaNbPO) was obtained by a molten salt method, which is a polymorph of niobium phosphate bronze NaNbPO. CS-NaNbPO displays high structural similarity to the noncentrosymmetric NaNbPO phase (referred to as NCS-NaNbPO): Distorted NbO octahedra are corner-coordinated to form ReO-type layers, which are further joined together by isolated PO tetrahedra. However, two polymorphous phases adopt different packings of structural units, resulting in distinct symmetries.

Synthesis, Structure, and Optical Properties of a 0D Hybrid Organic-Inorganic Metal Halide (CNHCl)GeCl.

Due to the flexible structural tunability and excellent photoelectric performance, hybrid organic-inorganic metal halides (OIMHs) have attracted intensive attention and become a hot topic in the field of materials. It is important and necessary to explore new OIMHs and study their structure-property relationship. In this work, a new lead-free OIMH, (CNHCl)GeCl, is synthesized by the combination of hydrothermal and solution methods.

Antimony Doping Enabled Photoluminescence Quantum Yield Enhancement in 0D Inorganic Bismuth Halide Crystals.

Owing to the exterior self-trapped excitons (STEs) with adjustable fluorescence beams, low-dimensional ns-metal halides have recently received considerable attention in solid-state light-emitting applications. However, the photoluminescence (PL) mechanism in metal halides remains a major challenge in achieving high efficiency and controllable PL properties because the excited-state energy of ns conformational ions varies inhomogeneously with their coordination environments. Here, a novel zero-dimensional (0D) lead-free bismuth-based RbBiCl·0.

Co-substitution design: a new glaserite-type rare-earth phosphate KRbSc(PO) with high structural tolerance.

An alkali rare-earth phosphate KRbSc(PO) was successfully obtained as a derivative of glaserite-type KNa(SO) by co-substitution of K(1)O → RbO, K(2)O → KO, NaO → ScO and SO → PO, while maintaining the original anionic framework. KRbSc(PO) exhibits a layered [Sc(PO)] framework built from ScO octahedra and PO tetrahedra, with K and Rb residing in the interlayers. Its isostructural lanthanide analogues KRbEr(PO) and KRbLu(PO), inspired by an elemental substitution strategy, were also prepared by a high-temperature solid state reaction.

Improvement on Magnetocaloric Effect through Structural Evolution in Gadolinium Borate Halides BaGd(BO)X (X = F, Cl).

A new Gd-containing borate BaGd(BO)F has been successfully grown via the high-temperature solution method using BaF-NaF-BO flux. BaGd(BO)F crystallizing in the orthorhombic space group is with lattice parameters = 7.571(4) Å, = 10.

Synthesis, Crystal Structure, and Nonlinear-Optical Properties of a Diamond-Like Chalcogenide CuGeS.

Metal sulfides with diamond-like (DL) structures generally exhibit excellent mid-IR nonlinear-optical (NLO) properties. Here, CuGeS (CGS) as a member of the DL chalcogenides was synthesized by a high-temperature solid-state method, and the optical properties were carefully studied experimentally and theoretically. The results revealed that CGS has a large second harmonic generation (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.

Atomic Substitution to Tune ScO Distortion in BaMSc(BO) (M = Na, K, Ba) to Acquire a Large Birefringence.

Replacing alkali metals (K, Na atoms) by an alkaline-earth metal (Ba atom), α-BaSc(BO) (high-temperature phase) is successfully obtained by a molten salt method, taking BaKNaSc(BO) as the parent template. Although both of them exhibit similar layered structures composed of ScO and BO units, α-BaSc(BO) shows largely distorted ScO octahedra (Δ = 0.56) forced by the uniform tension of a larger space effect from BaO polyhedrons, rather than regular ScO octahedra like in BaKNaSc(BO).

ε-La(IO): A Polar Iodate with High Thermal Stability and a Large Second-Harmonic-Generation Response Obtained by a Supercritical Hydrothermal Method.

The synthesis conditions at high temperature and high pressure are favorable for exploring new compounds with novel structures and properties. In this work, a new polar iodate, ε-La(IO), is obtained by a supercritical hydrothermal method with high temperature and high pressure ( = 400 °C and ≈ 25 MPa). Different from the known phases, ε-La(IO) crystallizes in the chiral space group 2, which features a three-dimensional framework with multiple IO groups stacked along different directions around the LaO polyhedra.

(CNH)GeBr: A 2D Organic Germanium Bromide Perovskite with Strong Orange Photoluminescence Properties.

Hybrid organic-inorganic metal halide (OIMH) perovskites are regarded as potential photoluminescent (PL) materials and have attracted intensive attention. Here, we select 1-methylpiperazine as an organic component and successfully obtain a two-dimensional (2D) Ge-based OIMH perovskite, (1-mpz)GeBr. It features a 2D layered structure composed of distorted [GeBr] octahedra with organic (CHN) located between the layers.

Investigation into Structural Variation from 3D to 1D and Strong Second Harmonic Generation of the AHgPS (A = Na, K, Rb, Cs) Family.

The continuous exploration of multinary chalcogenide semiconductors has provided a variety of new functional materials. In this paper, four new quaternary chalcogenides AHgPS (A = Na, K, Rb, Cs) have been prepared by solid-state syntheses. These findings complement the lack of research on this quaternary system.

NaGaIOF: a new alkali metal gallium iodate combined with IO and IOF units.

Birefringent crystals are very important optical materials, which are widely used in the fields of optics and communication. In this work, we reported a new iodate, NaGaIOF, synthesized by mild hydrothermal method. NaGaIOF crystallized in the monoclinic space group P2/c (No.

AZn(OH)(CNO) (A = Mg, Zn): Two Zn-Based Cyanurate Crystals with Various Cation Coordination and Large Birefringence.

Cyanurate crystals have recently become a research hot spot in birefringent materials owing to the large structural and optical anisotropy of the planar π-conjugated (HCNO) ( = 0-3) groups. In this study, two new Zn-based cyanurate crystals, Zn(OH)(CNO) and MgZn(OH)(CNO), were synthesized by the hydrothermal method. In Zn(OH)(CNO), the d Zn cations have three different coordinating environments, which has never been found in cyanurates.

Deep-Ultraviolet Nonlinear-Optical van-der-Waals Beryllium Borates*.

Van-der-Waals (vdW) deep-ultraviolet (DUV) nonlinear-optical (NLO) materials hold great potential to extend DUV NLO applications to two dimensions, but they are rare in nature. In this study, we propose a design principle to realize vdW DUV NLO materials via structural evolution from the non-vdW (BO )-(BeO F) layers in KBe BO F (KBBF) to the vdW (BO )-(BeO H) layers in berborite Be BO H (BBH) and the vdW (BO )-(BeO ) layers in beryllium metaborate BeB O (BEBO). Based on first-principles calculations, the fundamental NLO properties of BBH and BEBO demonstrate that a balanced DUV NLO performance can be achieved in these two systems.

LiZn(OH)CO : A Deep-Ultraviolet Nonlinear Optical Hydroxycarbonate Designed from a Diamond-like Structure.

Deep-ultraviolet (DUV) nonlinear optical (NLO) crystals are vital to the development of science and state-of-the-art technologies, but the exploration of these important optoelectronic materials is hindered by the contradiction between NLO effect and energy band gap as well as the sensitivity of DUV phase-matching to optical birefringence. Here, in order to achieve a well balanced DUV NLO performance, we chose the diamond-like structure as the prototype template for the material design and synthesized the first DUV NLO hydroxycarbonate crystal, LiZn(OH)CO . This compound simultaneously has a wide band gap (>6.

Nonlinear Optical Oxythiophosphate Approaching the Good Balance with Wide Ultraviolet Transparency, Strong Second Harmonic Effect, and Large Birefringence.

Ultraviolet (UV) transparency, second harmonic effect and optical birefringence are three vital but mutually restrictive factors in the application of UV nonlinear optical (NLO) materials. It is difficult for traditional phosphates to achieve a good balance among these factors. In this communication, we propose that the structural evolution of the NLO motif from traditional phosphate to oxythiophosphate would enhance the birefringence and second harmonic generation (SHG) effect while maintaining wide UV transparency, which is confirmed by first-principles calculations and preliminary experimental measurements.

NaCdGeS: A Sodium-Rich Quaternary Wide-Band-Gap Chalcogenide with Two-Dimensional [GeCdS] Layers.

Metal chalcogenides are an attractive subject for investigation owing to their wide application in optoelectronics. Here, we report the discovery of a new cadmium-based quaternary sulfide, NaCdGeS, with a wide band gap of 3.35 eV.

Selenite bromide nonlinear optical materials PbGaF(SeO)Br and PbNbO(SeO)Br: synthesis and characterization.

Two new isomorphic selenite bromides, namely Pb2GaF2(SeO3)2Br (1) and Pb2NbO2(SeO3)2Br (2), were synthesized by mild hydrothermal reactions. These two compounds crystallize in the noncentrosymmertric space group P21 and feature 3D structures consisting of 1D (Pb2Br)3+ cationic chains and 2D [Ga2F4(SeO3)4]6-/[Nb2O4(SeO3)4]6- anonic chains. As measured, 1 and 2 are phase-matchable and exhibit excellent second harmonic generation (SHG) responses of 4.

Nonlinear-Optical Crystal RbYBO with Condensed BO Blocks That Exhibits an Intriguing Structural Arrangement and a Short Ultraviolet Absorption Edge.

Nonlinear-optical (NLO) crystals, which can regulate the laser wavelength through a cascading second-harmonic-generation technique, have been widely utilized in the field of optoelectronics. In this work, we grew the NLO borate crystal RbYBO (RYBO) using the spontaneous crystallization method. RYBO crystallizes in a chiral trigonal space group of 32 with a new type of structural arrangement built from Y-O short chains and BO groups.