Three-in-One Tetrahedral Functional Units Constructing Diamondlike Ag 2 In 2 SiS 3.06 Se 2.94 with High-Performance Nonlinear-Optical Activity.

Exploration of new functional materials with enhanced performance from known ones is always an attractive strategy. A new infrared (IR) nonlinear-optical (NLO) mixed chalcogenide Ag 2 In 2 SiS 3.06 Se 2.94 ( 1 ), was obtained through partial congener substitution originated from Ag 2 In 2 SiS 6 ( 0 ). 1 crystallizes in the monoclinic space group Cc , and its three-dimensional (3D) polyanionic network is composed of {[In 4 Si 2 Se 5 (S/Se) 11 ] 12- } ∞ helical chains sharing S/Se(5) corner atoms with cavities embedded with counterion Ag + ions. It exhibits a much enhanced NLO response compared to that of 0 , reaching 1.1 × AgGaS 2 . Further theoretical analysis results indicate that the large NLO response can be attributed to the synergistic effect of AgQ 4 and InQ 4 tetrahedral functional motifs. This work not only reports a new high-performance IR NLO material but also enriches the partial ion substitution strategy to obtain new functional materials.