Na₂B₆O₉F₂: A Fluoroborate with Short Cutoff Edge and Deep-Ultraviolet Birefringent Property Prepared by an Open High-Temperature Solution Method

Abstract

As important materials in modulating the polarization of light, birefringent crystals have attracted considerable attention and played crucial roles in the field of optical communication and the laser industry. Limited by the transparency range, few birefringent crystals can be used in the deep-ultraviolet (DUV) region, except for α-BaBO (α-BBO). However, the application of α-BBO in the DUV range is restricted by the relatively high cutoff edge and low transmittance rate below 200 nm. In this paper, we design and synthesize a new fluoroborate, NaBOF, by introducing fluorine into borate system. It possesses a short cutoff edge of 169 nm and birefringence larger than 0.080 at 589.3 nm. The NaBOF crystals with sizes up to 3.0 mm × 1.5 mm × 0.2 mm have been grown with good quality by a high-temperature solution method in the open system. First-principles calculations were carried out to understand the optical properties.

Sn[B2O3F2]—The First Tin Fluorooxoborate as Possible NLO Material

“…Fluorooxoborates should comprise sufficiently large bandgaps in the UV as well as preferential formation of non‐centrosymmetric structures, thus making them ideal candidates for SHG materials in the UV. Beyond that, they normally combine the birefringence promoting triangular BO 3 or tetrahedral BO 3 F moieties providing terminal fluorine atoms with a proclivity for weak coordination . Recent calculations as well our own results confirm these considerations and suggest a boost for NLO materials based on so‐called fluorooxoborates.…”

CsB4O6F: A Congruent‐Melting Deep‐Ultraviolet Nonlinear Optical Material by Combining Superior Functional Units

“…Thep lanar BO 3 triangles with the B À Ob ond lengths varying from 1.342 (14) to 1.413(14) are common in other borates,w hile the BO 3 Ft etrahedra are distorted with the BÀFb onds equaling 1.417 (8) and BÀOb onds in the range of 1.435(13)-1.468(16) .The BÀO/F bond lengths and O-B-O/F angles are comparable to recently reported fluorooxoborates. [11,12] Thee xistence of the B À Fb onds was further confirmed by elemental analysis,b ond valence calculation (Table S3) and IR spectrum ( Figure S5). TheF BB of CBF is the B 4 O 8 Fg roup,w hich is composed of three BO 3 triangles forming B 3 O 6 rings and one BO 3 Ftetrahedron that is cornershared through oxygen atoms (Figure 1a).…”

“…Based on the earlier successful synthesis of fluorooxoborates, [11] we obtained CBF using solid-state method in open air.T he phase purity was checked by powder X-ray diffraction (PXRD,see Figure S1 in the Supporting Information). A crystal of CBF with dimension of 4mm 4mm 3mmw as grown from its stoichiometric melt ( Figure S2).…”

The First Alkaline‐Earth Fluorooxoborate Ba[B4O6F2]—Characterisation and Doping with Eu2+

“…For instance, borates also allow forat rigonal planar coordination of the network buildingc ation boron. The inorganic fluorooxoborates known so far comprise trivalent bismuth [6,7] and mainly alkali metal as well as ammonium cations, [8][9][10][11][12][13][14][15][16][17][18][19][20] which were investigated with regard to their behaviour as ionicc onductors or their nonlinear opticalproperties.…”