Recent progress in oxychalcogenides as IR nonlinear optical materials

Currently, non-centrosymmetric oxychalcogenides, a class of newly developed heteroanionic compounds, have emerged as promising candidates for IR nonlinear optical (NLO) materials due to the fact that they can combine the impressive second-harmonic generation (SHG) responses of chalcogenides with the wide energy gaps of oxides. Moreover, multiple combinations of chalcogens and the oxygen element would, in principle, lead to more new frequency-doubling building units, enabling the extensive seeking and design of new NLO-active oxychalcogenides. In this Frontiers article, the recent developments of oxychalcogenides as IR-NLO candidates are summarized. These materials can be grouped into three types in terms of their structural dimensions: (i) two-dimensional layered CaZnOS, SrZn2OS2, Sr8Ga8O3S14, Sr6Cd2Sb6O7S10 and Sr4Pb1.5Sb5O5Se8; (ii) one-dimensional chain-typed AEGeOQ(2) (AE = Sr and Ba; Q = S and Se); and (iii) zero-dimensional molecular Sr3Ge2O4Se3 and alpha-Na3PO3S. We discuss the rich coordination environment of mixed-anion frequency-doubling building units focusing on the correlations between their non-centrosymmetric structures and NLO properties, as well as their synthetic methods. Finally, the present challenges and future perspectives in this field are also proposed.

Automated summary

Recent developments in non-centrosymmetric oxychalcogenides show their potential as promising candidates for IR nonlinear optical applications. By categorizing them based on their structural dimensions, exploring the correlations between their properties and synthetic methods, new insights have been gained in this field. Challenges and future perspectives were also discussed.