New nonlinear optical-active AAgGa6S10 (A = K, Rb, Cs) featuring {[AgGa6S10]-}∞ framework and high laser damage threshold.

Obtaining new nonlinear-optical (NLO) materials with strong responses and wide band gaps is a hot topic in the laser field. Here, a series of sulfides AAgGa6S10 (A = K, Rb, Cs) were obtained by a facile solid-state reaction routine. They crystallize in the noncentrosymmetric space group Cc with a new structure-type. Their 3D structures are built by an unprecedented {[AgGa6S10]-}∞ anionic framework, which can be considered as the 1 : 1 intergrowth of the AgGaS2 and Ga2S3 structural slabs. They exhibit moderate responses ∼0.7/0.5/0.6 × AGS and the widest bandgaps among NLO chalcogenides containing independent Ag sites, suggesting that they may have high laser-induced damage thresholds, which is verified by the experimental 1.5/3/4 × AGS. This study not only opens a new system of NLO materials, but also provides a reliable design strategy for future NLO materials.