Perfectly Encoding π‐Conjugated Anions in the RE₅(C₃N₃O₃)(OH)₁₂ (RE=Y, Yb, Lu) Family with Strong Second Harmonic Generation Response and Balanced Birefringence

Abstract

Nonlinear optical (NLO) crystal, which simultaneously exhibits strong second‐harmonic‐generation (SHG) response and desired optical anisotropy, is a core optical material accessible to the modern optoelectronics. Accompanied by strong SHG effect in a NLO crystal, a contradictory problem of overlarge birefringence is ignored, leading to low frequency doubling efficiency and poor beam quality. Herein, a series of rare earth cyanurates RE5(C3N3O3)(OH)12 (RE=Y, Yb, Lu) were successfully characterized by 3D electron diffraction technique. Based on a “three birds with one stone” strategy, they enable the simultaneous fulfillment of strong SHG responses (2.5–4.2× KH2PO4), short UV cutoff (ca. 220 nm) and applicable birefringence (ca. 0.15 at 800 nm) by the introduction of rare earth coordination control of π‐conjugated (C3N3O3)3− anions. These findings provide high‐performance short‐wavelength NLO materials and highlight the exploration of cyanurates as a new research area.

From H12C4N2CdI4 to H11C4N2CdI3: a highly polarizable CdNI3 tetrahedron induced a sharp enhancement of second harmonic generation response and birefringence

“…These crystals feature many advantages such as the availability of a wide range of organic components, tunability of inorganic structures, and ease of single crystal growth. [11][12][13][14][15] Notably, the compounds containing p-conjugated organic moieties have attracted the most attention, and many promising NLO materials in such classes have been reported, such as KLi(HC 3 N 3 O 3 )$2H 2 O (5.3 × KDP), 11 Lu 5 (C 3 N 3 O 3 )(OH) 12 (4.2 × KDP), 12 C(NH 2 ) 3 SO 3 F (5 × KDP), 13 (C 5 H 6 ON) + (H 2 PO 4 ) − (3 × KDP), 14 and [o-C 5 H 4 NHOH] 2 [-I 7 O 18 (OH)]$3H 2 O (8.5 × KDP). 15 Alongside these compounds, several organic-inorganic metal halides (OIMHs) formed from the combination of a p-conjugated organic cation with a metalhalide polyhedron have also been discovered to show NLO performance, such as (H 7 C 3 N 6 )(H 6 C 3 N 6 )MCl 3 (M = Hg and Zn; 5 × and 2.8 × KDP), 16,17 [C 18 H 21 N 4 ][AgX 3 ]X (X = Cl, Br, and I, 6.2, 6.5 and 7.6 × KDP), 18 a-(CN 3 H 6 ) 3 Cu 2 I 5 (1.8 × KDP), 19 and (C 6 H 11 N 2 )PbBr 3 (8 × KDP).…”

Cs[B3O3F2(OH)2]: discovery of a hydroxyfluorooxoborate guided by selective organic–inorganic transformation

“…Organic and inorganic compounds garner substantial interest as active materials for batteries, nonlinear optics, etc. 1 Attempts have been made 2–4 to (i) synthesize and functionalize these two independent branches; (ii) combine them to design organic–inorganic hybrid materials; and (iii) achieve the selective transformation between them. Although these three main research areas are not necessarily independent of one another, the last one is often still a considerable challenge.…”

From Centrosymmetry to Noncentrosymmetry: Precise Structural Regulation and Characterization on ZnHPO3·2H2O Polymorphs

“…Among these, the rational combination of different NLO-active groups has been widely recognized as an efficient strategy to enhance the NLO properties. Asymmetric units with high polarizability, such as π-conjugated groups, d 0 cations with second-order Jahn-Teller distortion, cations with stereochemically active lone pairs, and asymmetric tetrahedral groups, have attracted continuous research attention, and a bunch of new NLO materials with enhanced properties have been developed recently. − …”