Deep-ultraviolet Cut-off Edge Research Articles

Two Hydroxyfluorooxoborates Achieving Deep-Ultraviolet Cutoff Edges and Moderate Birefringence by Assembling Multi-Anionic Groups.

Assembling multi-anionic groups is conducive to utilizing respective advantage to achieve the enhancement of optical performance. Two new hydroxyfluorooxoborates, Ama2-Rb2B3O3F4(OH) and K8Cs2B15O14(OH)7F20 ⋅ H2O with [B3O3F4(OH)] six-membered rings were synthesized for the first time. The title compounds exhibit short ultraviolet cutoff edges (<200 nm) and K8Cs2B15O14(OH)7F20 ⋅ H2O possesses a moderate experimental refractive index difference of 0.051@546 nm.

Rb3MgB5O10 and LiBaAl(BO3)2: covalent tetrahedra MO4-containing borates with deep-ultraviolet cutoff edges.

Borates are favored by materials scientists and chemists because of the significant electronegativity difference between B and O atoms and their flexible assembly modes resulting in abundant structures and excellent properties. For the design of deep-ultraviolet (DUV) optical crystals with excellent macroscopic performance, it is crucial to choose appropriate cations and anionic groups and microscopically reasonable assembly patterns. Herein, by introducing covalent tetrahedra ([MO4], M = Mg, Al), two new mixed alkali metal and alkaline earth metal borates, Rb3MgB5O10 and LiBaAl(BO3)2, were synthesized using the melt method and high-temperature solution method. They contain M-B-O two-dimensional (2D) layers (2∞[MgB5O10] and 2∞[Al(BO3)2], respectively) composed of isolated B-O groups ([B5O10]5- and [BO3]3-, respectively) and metal-centered tetrahedral connectors ([MgO4]6- and [AlO4]5-, respectively). Combining experiments and theoretical calculations shows that the two compounds have short cutoff edges (<200 nm) and moderate birefringences. Further analysis manifests that the isolated [MO4] covalent tetrahedra can optimize the arrangement of anion groups, guarantee the balanced optical properties of materials, and point out the direction for further exploration of novel borate structures.

Ba2B9O13F4·BF4: first fluorooxoborate with unprecedented infinite [B18O26F8] tubes and deep-ultraviolet cutoff edge

Ba2B9O13F4·BF4: first fluorooxoborate with unprecedented infinite [B18O26F8] tubes and deep-ultraviolet cutoff edge

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, (NH4)2{Mg(H2O)2[B6O7(OH)6]2}·2H2O, was successfully synthesized by a mild hydrothermal method at a relatively low temperature. A brief review was performed to show the participation of NH4+ in the recent development of optical materials. By discussing the optimum synthesis method of ammonium-containing borates and the main factors affecting the dimensionality of B-O anionic groups in their structures, the design strategy for synthesizing ammonium-containing borate and adjusting its structure has been put forward. Relevant experimental measurement results and the first-principles calculation results show that the title compound has a deep-UV cutoff edge (<200 nm) and moderate birefringence (Δncal. = 0.064 @546 nm), which indicates its potential application in the deep-UV region.

BaB2P2O8F2: A Fluoroborophosphate with [B2P2O8F2]∞ Layers and Deep-Ultraviolet Cutoff Edge.

A fluoroborophosphate, BaB2P2O8F2, was successfully obtained. Its structure contains a novel [B2P2O8F2]∞ layer containing six-membered rings, which is formed by the fundamental building block composed of three types of non-π-conjugated groups, [PO4], [BO4], and [BO2F2]. BaB2P2O8F2 has a deep-ultraviolet (DUV) cutoff edge (λ < 200 nm) and a tiny birefringence (Δn = 0.007 at 532 nm), which originates from the constituent non-π-conjugated groups. The title compound enriches the versatility of the fluoroborophosphates, encouraging further research into DUV materials in fluoroborophosphate systems.

A series of novel phosphites/phosphates with deep-ultraviolet cut-off edges from 0D polar to 3D non-polar architectures

Four new phosphites/phosphates were designed and prepared; three of them exhibit a deep UV cutoff edge of ∼190 nm and NLO material Ca[HPO3] shows a phase-matching behavior.

Na2SrB16O26: a new borate with independent interpenetrating B-O networks and deep-ultraviolet cutoff edge.

A new borate, Na2SrB16O26, was synthesized by the high-temperature solution method. It exhibits complicated interpenetrating 3D B-O frameworks composed of the functional building block (FBB) [B8O16]. The UV-vis-NIR diffuse reflectance spectroscopy shows that it has a deep-ultraviolet (DUV) cutoff edge (<200 nm). The relationship between the structures and optical properties was uncovered by theoretical calculations. By the first-principles calculation, the birefringence is estimated to be 0.07 at 1064 nm. The response electron distribution anisotropy (REDA) analysis indicates that the [BO3] units contribute mainly to the generation of the moderate birefringence.

Sc2F2(B2O5): a deep ultraviolet scandium borate fluoride exhibiting large birefringence induced by the synergistic effect of B2O5and ScOnF2groups

A rare earth borate fluoride, Sc2F2(B2O5), displays a deep ultraviolet cutoff edge (&lt;200 nm) and very large birefringence induced by the synergistic effect of B2O5and ScOnF2groups.

Sr5(CO3)2(BO3)2: A new family member of isostructural mixed borate and carbonate Ba4M(BO3)2(CO3)2 (M = Ba, Sr) with isolated BO3 and CO3 groups

A new mixed borate and carbonate Sr5(CO3)2(BO3)2, which is isostructural with Ba4M(BO3)2(CO3)2 (M = Ba, Sr), has been synthesized by hydrothermal method. It crystallizes in Pnma (No. 61) space group with the lattice parameters a = 7.387(4), b = 16.556(9) and c = 8.971(5) Å (Z = 4). This structure features a three-dimensional (3D) network including SrO8 polyhedra, isolated BO3 and CO3 triangles. UV-Vis-NIR diffuse reflectance spectrum for Sr5(CO3)2(BO3)2 indicates that it has a deep ultra-violet cut-off edge of 190 nm. In addition, crystal structural comparison among mixed borates and carbonates shows that the interaction between boron-oxide groups and CO3 groups leads to different arrangements of anionic groups, which can be classified into three types according to the connection of boron-oxide groups. An analysis of theoretical calculations based on density functional theory was also performed to understand the relationships between the structures and properties.

Li3La2(BO3)3 and Li1.75Na1.25La2(BO3)3: A Great Enhancement in Birefringence Induced by Optimal Arrangement of π-Conjugated [BO3] Units.

In virtue of the essential role in controlling polarized light, outstanding ultraviolet (UV) and deep-ultraviolet (DUV) birefringent crystals are imperative in many advanced optical instruments. To design the UV and DUV crystals with large birefringence, we paid more attention to combining the excellent gene, π-conjugated [BO3] unit and metal cations beneficial to blue-shift the cutoff edge; finally, two rare-earth borates Li3La2(BO3)3 and Li1.75Na1.25La2(BO3)3 have been synthesized using the high-temperature solution method. Compared with Na3La2(BO3)3, Li3La2(BO3)3 and Li1.75Na1.25La2(BO3)3 are isostructural, and the isolated [BO3] units are arranged nearly parallel to each other in the structure, which is conducive to generating a larger birefringence. The structural comparison between the two crystals and Na3La2(BO3)3 indicates that the various coordination environments of alkali metal cations play an important role in the evolution of the crystal structure from Li3La2(BO3)3 and Li1.75Na1.25La2(BO3)3 to Na3La2(BO3)3. This work can contribute to a better understanding of the enhancement in birefringence from Na3La2(BO3)3 (0.023 @ 1064 nm) to Li3La2(BO3)3 (0.078 @ 1064 nm) with the perspective of structure-property relationships. Meanwhile, the two title crystals possess the DUV cutoff edge (<190 nm), suggesting that they can be applied as the DUV birefringent crystals.

La2SrB8O16: A new rare earth borate with [B8O20]16− groups exhibiting a deep ultraviolet cutoff edge

A new rare-earth borate crystal La2SrB8O16 (LSB8) has been grown by means of spontaneous crystallization for the first time. It crystallizes in triclinic space group P1¯ (No. 2), and the lattice parameters are a ​= ​4.7512(4) Å, b ​= ​7.1202(5) Å, c ​= ​8.0147(5) Å, α ​= ​76.629(2)°, β ​= ​77.934(2)°, γ ​= ​86.588(3)°, and Z ​= ​1, respectively. LSB8 has a layered structure, which is constituted of centrosymmetric B8O20 groups. Its spectral characteristics were detailedly investigated. The electronic band, refractive indices, and density state of LSB8 were calculated according to the first principles.

Ba2B7O12F with novel FBB [B7O16F] and deep-ultraviolet cut-off edge

A new fluorooxoborate Ba2B7O12F features novel FBB [B7O16F] and two different sizes of channels in its anionic structure, which possesses a deep-ultraviolet cutoff edge of 180 nm and a large bandgap of 6.67 eV.

Cs3B3O3F6 with a Deep-Ultraviolet Cutoff Edge and a Suitable Birefringence as the Potential Zero-Order Waveplate Material.

The zero-order waveplates, the essential materials in altering the polarization state of optical waves, are significant in polarimetry and the laser industry. Restricted by birefringence and absorption edge, few materials can have moderately small birefringence (Δn < 0.01) and a deep-ultraviolet (DUV; λ < 200 nm) transparency range. We used the B3O3F6 unit for designing the zero-order waveplate material, which is composed of three BO2F2 tetrahedra interconnected by corner sharing. Here we obtained a new Cs3B3O3F6 compound with the isolated B3O3F6 unit by a high-temperature solution method, which has the DUV cutoff edge and suitable birefringence (0.0069 at 532 nm) based on the experimental and computational results. This demonstrates that the isolated B3O3F6 unit is a potential group, which favors the search for suitable compounds for DUV zero-order waveplate materials.

Syntheses, characterization, and theoretical calculation of Rb2Mg3(P2O7)2 polymorphs with deep-ultraviolet cutoff edges

By the combination of the isolated P2O7 dimers and MgO4 tetrahedra, α- and β-Rb2Mg3(P2O7)2 polymorphs were synthesized by a high-temperature solution method. α-Rb2Mg3(P2O7)2 crystallizes in non-centrosymmetric space group P 212121, while β-Rb2Mg3(P2O7)2 crystallizes in centrosymmetric P 21/ c . Both structures contain a three dimensional [Mg3P4O14]2− anionic framework, while Rb+ cations are in the space. Structure analyses show that the isolated P2O7 dimers can easily adjust their variable configurations and orientations to fit the different coordination environments of the cations, which is conducive to the formation of polymorphs. The phase transformation process from α- to β-Rb2Mg3(P2O7)2 was further investigated by powder X-ray diffraction and thermal gravimetric/differential scanning calorimetry measurements. In addition, UV-vis-NIR diffusion spectra indicate both materials have deep-ultraviolet cut-off edges (below 190 nm). α-Rb2Mg3(P2O7)2 is second-harmonic generation (SHG)-active and the origin of SHG response was investigated by the SHG density calculations. The first-principle calculations were also carried out to illuminate their structure-property relationships.

BaB2 O3 F2 : A Barium Fluorooxoborate with a Unique [B2 O3 F]- Layer and Short Cutoff Edge.

Substitution of oxygen by fluorine in the borate group offers a materials platform from which intriguing structure and functionality may arise. Herein, we report a new fluorooxoborate, BaB2 O3 F2 , synthesized by introducing the F atoms into the BaO-B2 O3 system. BaB2 O3 F2 exhibits a unique oxyfluoride layer [B2 O3 F]- and a deep-ultraviolet cutoff edge below 180 nm. The effect of the introduction of F atoms on the structure and optical property of the borate group has been investigated; this should be useful to further expand borate chemistry and materials.

LiGeBO4: a nonlinear optical material with a balance between deep-ultraviolet cut-off edge and large SHG response induced by hand-in-hand tetrahedra

LiGeBO4is found to be a material that can balance a large band gap (&gt;6.2 eV) and strong SHG coefficient (2 × KDP), which is rarely seen in tetrahedral-based crystals.

Ba3Mg3(BO3)3F3 polymorphs with reversible phase transition and high performances as ultraviolet nonlinear optical materials

Nonlinear optical (NLO) materials are the vital components of future photoelectric technologies as they can broaden the tunable wavelength range supplied by common laser sources. However, the necessary prerequisites for a practical NLO material are rather strict. Accordingly, considerable efforts have been focused on finding potential NLO materials. Here we report two asymmetric beryllium-free borates Pna21- and Pbar 62m-Ba3Mg3(BO3)3F3 featuring NLO-favorable 2∞[Mg3O2F3(BO3)2] layered structures. The reversible phase transition among two polymorphs was demonstrated by multiple experimental tests. The optical measurements reveal that Pna21-Ba3Mg3(BO3)3F3 possesses the optical properties required for ultraviolet NLO applications. Remarkably, Pna21-Ba3Mg3(BO3)3F3 has a large laser damage threshold, a deep-ultraviolet cutoff edge, a favorable anisotropic thermal expansion as well as the capacity of insolubility in water. These optical properties can be comparable or superior to that of commercial NLO material β-BaB2O4, which make Pna21-Ba3Mg3(BO3)3F3 a promising ultraviolet NLO material.

Non-centrosymmetric BaNaP3O9 with a short deep-ultraviolet cutoff edge

A new nonlinear optical (NLO) material, namely, BaNaP3O9 was synthesized by high temperature solution method using PbO as the flux. Crystal of BaNaP3O9 with the non-centrosymmetric P212121 space group displays a novel topological three dimensional (3D) structure with tremendous [Ba4Na4O40] 16-membered ring (16-MR) composed by the BaO8, NaO6 polyhedra, which alternately connected each other by sharing two oxygen atoms. The phosphate compound has a short deep-ultraviolet (deep-UV) cut-off edge about 177 nm and shows a second harmonic generation (SHG) response (0.3 × KDP). Some related optical properties and electronic structures derived from first-principles calculations, were explored.

The first lead fluorooxoborate PbB5O8F: achieving the coexistence of large birefringence and deep-ultraviolet cut-off edge.

Herein, the first lead fluorooxoborate PbB5O8F has been structurally designed following a strategy of fluorine introduction into borates. PbB5O8F presents the first case of possessing the [B5O10F]6- fundamental building block. More importantly, PbB5O8F fully achieves the coexistence of large birefringence and deep-ultraviolet cut-off edge. This short cut-off edge sets a new record among lead borates.

The structural diversity of halogen-centered secondary building units: two new mixed-metal borate halides with deep-ultraviolet cut-off edges.

Two new mixed-metal borate halides, namely, NaMg2Ba7B14O28F5 (I) and NaBa4B10O18BrF2 (II), were synthesized using the high-temperature flux method. Both structures were characterized by single-crystal X-ray diffraction, and their structures are shown to feature complicated three dimensional (3D) networks with different types of halogen-centered secondary building units (SBUs). Specifically, compound I contains three spatial fluorine-centered SBUs F(1)Ba4Mg2, F(2)Ba(Na)Ba3Mg, and F(3)Ba(Na)Ba2Mg, while compound II exhibits spatial FBa3Na and planar BrBa4 fluorine- or bromine-centered SBUs. Furthermore, four categories of halogen-centered SBUs were investigated among all the 173 available anhydrous halogen-containing borates to elaborate the role of halogen atoms to enrich the structural diversity of borates. What's more, the crystal structures, thermal stabilities, and UV-Vis-NIR diffuse reflectance spectra of synthesised compounds I and II have also been determined.