M6PS5X (M = Ag, Cu; X = Cl, Br) chalcohalides exhibiting strong nonlinear optical responses and high laser damage resistances.

A series of M6PS5X (M = Ag, Cu; X = Cl, Br) nonlinear optical (NLO) chalcohalides with special MS3X ligands have been synthesized in this work. Their critical optical performances were systematically measured and the research results show that all of them exhibit strong NLO responses (2.0-2.7 × commercial AgGaS2) and high laser-damage thresholds (1.7-2.3 × AgGaS2), indicating their potential application as good NLO candidates. Furthermore, first-principles calculations were used to study their inherent structure-property relationships and chalcohalides can be expected to be optimal systems for the exploration of new promising IR NLO crystals.