Sr6Cd2Sb6O7S10: Strong SHG Response Activated by Highly Polarizable Sb/O/S Groups

摘要

A new nonlinear optical (NLO) oxysulfide, Sr6Cd2Sb6O7S10, which contains the functional groups [SbOxS5-x](7-) (x=0, 1) with a 5s(2) electron configuration, is synthesized by a solid-state reaction. This compound displays a phase-matchable second harmonic generation (SHG) response four times stronger than AgGaS2 (AGS) under laser irradiation at 2.09 mu m. Single-crystal-based optical measurements reveal a SHG intensity that can be tuned by temperature and novel photoluminescence properties. Theoretical analyses demonstrate that tetragonal [SbOS4](7-) and [SbS5](7-) pyramids make the predominant contribution to the enhanced SHG effect. Among those, the [SbOS4](7-) units with mixed anions make a larger contribution. This work proposes that oxysulfide groups with an ns(2) electron configuration can serve as new functional building units in NLO materials and opens a new avenue for the design of other optoelectronic materials.