From thiophosphate to chalcohalide: mixed-anion AgSxCly ligands concurrently enhancing nonlinear optical effects and laser-damage threshold

Abstract

In this study, we propose a new design strategy that introduces unique mixed-anion AgS_xCl_y ligands into thiophosphate to afford a successful synthesis of a promising Ag₅PS₄Cl₂ IR NLO chalcohalide. Compared with chlorine-free Ag₃PS₄, Ag₅PS₄Cl₂ undergoes overall performance enhancement and achieves a good balance between large NLO effect (2.0 × Ag₃PS₄) and high laser damage threshold (3.8 × Ag₃PS₄). Theoretical analysis further indicates that AgS_xCl_y groups are the new superior NLO-active units since they can maintain the wide bandgap while concurrently making a great contribution to the origin of NLO effects. Therefore, the incorporation of AgS_xCl_y groups into the crystal structure can be expected to be one feasible way to design new IR NLO candidates with excellent performance.