Sn₂B₅O₉Br as an Outstanding Bifunctional Material with Strong Second‐Harmonic Generation Effect and Large Birefringence

Abstract

The first tin (II) borate bromide, Sn2B5O9Br (SBOB), as an outstanding bifunctional material with excellent linear and nonlinear optical (NLO) performance is synthesized successfully. As far as it is known, it exhibits the largest birefringence among the reported borates (0.439 at 546 nm), even over famous birefringent materials YVO4 and TiO2. Meanwhile, it also owns a strong second harmonic generation (SHG) response of 2.4 times that of KH2PO4. Theoretical calculations display that its incredible optical properties mainly originate from the extremely intensive stereochemical activity lone pair (SCALP) of [SnO7Br2] polyhedra, which results in the enhancement of birefringence and SHG response, increasing to 2.6‐ and 4.8‐fold, respectively, from Sn2B5O9Cl (SBOC) to SBOB. These perceptions will guide and accelerate the exploration of excellent birefringence and NLO materials in tin (II)‐based compound.

Sn2PO4I: An Excellent Birefringent Material with Giant Optical Anisotropy in Non π‐Conjugated Phosphate

“…[33] Currently, the cations with stereochemical activity lone pairs could enhance birefringence based on theoretical calculation. [24,34] Subsequently, we prepared two new crystals Sn 2 B 5 O 9 Cl and Sn 2 B 5 O 9 Br, [35,36] and it experimentally demonstrated that [SnOX] (X = halogen) polyhedra can induce the large amplitude gain of birefringence.…”

“…Hence, Sn 2 PO 4 I presents a larger birefringence than Sn 2 PO 4 Br. [36] On the other hand, the birefringence of Sn 2 PO 4 I is larger than or equal to 0.664, which exceeds those of the reported inorganic borates and phosphates so far, such as SbB 3 O 6 , [19] Sn 2 B 5 O 9 Cl, [35] Sn 2 B 5 O 9 Br [36] and K 2 Sb-(P 2 O 7 )F. [25] In particular, the birefringence of Sn 2 PO 4 I is about 2.2 and 2.9 times those of commercial birefringent crystals YVO 4 and calcite @1064 nm, respectively (Figure 3). Sn 2 PO 4 I not only exhibits the larger birefringence, but also good stability (Figure S1c) and lower crystal growth temperature.…”

Tailored Ordered Structures with Functional Units of Distorted [NbO6] and Antiparallel [GeO4] for Enhanced Birefringence in Germanate Crystal

“…[1,2] Deciphering the complex relations between electron/phonon (e.g., coupling or decoupling) and the optical response of crystal, is a hot topic in optoelectronic functional materials. [3][4][5][6] For instance, birefringent materials can be capable of modulating the lights of polarization and underpinning crucial optical devices, mainly including calcite CaCO 3 , [7] borate a-BaB 2 O 4 , [8] rutile TiO 2 [9] and between germanate and vanadate, we select YVO 4 crystal as a template. Typically, YVO 4 featured simultaneously with active d 0 configured cations V 5+ and antiparallel arrangement of [VO 4 ] groups that contribute mainly to its birefringence, has been considered as one of the most practical birefringent crystals owing to its outstanding birefringence (∆n≈0.21) in the Vis-NIR region.…”

LiSrSbS3: parallel configurations of lone pair electrons inducing a large birefringence

“…35,36 The stereo-chemically active lone pair electron cations can be considered as a critical element in influencing the birefringence, for example, Sn 2+ with stereo-chemically activity enhancing the birefringence in BaSn 2 (PO 4 ) 2 37 and Sn 2 B 5 O 9 Br. 38 Antimony chalcogenides are an attractive subject because Sb III cations not only have lone pair of electrons in the [SbS 3 ] groups but also adopt diverse asymmetric local environments ([Sb III S n ], n = 3–6). 39–43 Typically, 1D or 2D structures tend to produce large birefringence, 44 the Sb 3+ ions have a variety of ligands ([Sb III S n ], n = 3–6), which may be linked together by sharing corners or edges to form fascinating structure motifs including 1D chains, 2D layers, and 3D network.…”