Oxychalcogenides: A Promising Class of Materials for Nonlinear Optical Crystals with Mixed‐Anion Groups

Abstract

Infrared nonlinear optical (IR NLO) materials are of great significance in the development of IR laser technology. But rationally designing high‐performance IR NLO materials remains a huge challenge due to the conflict between the necessary properties required for NLO materials. Notably, oxychalcogenides with mixed‐anion groups have drawn extensive interest as a family of important IR NLO candidates because they integrate the property advantages of oxides and chalcogenides by chemical substitution engineering. In this review, we provide a survey of reported oxychalcogenides and aim to present the development of NLO oxychalcogenides from the perspective of rational design of their structural chemistry. Furthermore, we focus on the relationships between partial substitution and structural symmetry as well as optical properties. These provide some helpful guidance for the further exploration and design of novel oxychalcogenide materials with excellent NLO performance in the future.

Eu2MGe2OS6 (M = Mn, Fe, Co): Three Melilite-Type Rare-Earth Oxythiogermanates Exhibiting Balanced Nonlinear-Optical Behaviors

“…As a newly developed class of mixed-anion compounds, most of the oxychalcogenides can be transformed from known oxides by partial anion substitution, which supplies a useful structural platform to study the structure–property relationships influenced by the heteroligand functional groups. With this in mind, the [GeOS 3 ], [GeO 2 S 2 ], and [GeO 3 S] units become interesting mixed-anion SHG units for MIR NLO materials, which can be obtained from [GeO 4 ] units in germanates by partial O-to-S substitution. − The above mixed-anion SHG units can produce large coordination polyhedral distortion, which is conducive to enhancing polarity and the NLO coefficient. Furthermore, they are conducive to forming large anisotropy because of the different sizes and electronegativities of the sulfur and oxygen elements, which is helpful to the acquisition of large birefringence (Δ n ) and phase-matchable (PM) behavior.…”

Sr6Ge3OSe11: A Rationally Designed Noncentrosymmetric Oxyselenide with Polar [GeOSe3] Building Blocks

“…Likewise, the quaternary Ba variant BaGeOSe 2 ( P 2 1 2 1 2 1 ) also adopts an NCS structure . This work aims to highlight oxychalcogenides as a promising materials class for NLO research and that PIAS is a useful strategy for generating NCS structures. − …”

A unique [Sb6O2S13]12−finite chain in oxychalcogenide Ba6Sb6O2S13leading to ultra-low thermal conductivity and giant birefringence

“…, high electronegativity O 2− and low electronegativity Q 2− ), have emerged as a new type of low-dimensional functional material in recent years. 11 Despite a great number of reports on novel oxychalcogenides with 1D and 2D structures so far, the exploration of 0D structures, especially for Sb-based oxychalcogenides, is quite limited. Hence, in this work, we take interest in the AE/Sb/O/Q (AE = alkaline-earth metal elements; Q = S, Se) system, hoping to obtain low-dimensional structures.…”