Balanced Second-Order Nonlinear Optical Properties of Adducts CHI3·(S8)3 and AsI3·(S8)3: A Systematic Survey

Two isostructural adducts CHI 3 ·(S 8 ) 3 ( 1 ) and AsI 3 ·(S 8 ) 3 ( 2 ) are synthesized by a simple solution method. Both of them crystallize in noncentrosymmetric R 3 m, featuring van der Waals interaction linked CHI 3 tetrahedra or SbI 3 trigonal pyramids with crown-like S 8 molecules. Both 1 and 2 show strong SHG responses and phase matchability under either 1.064 or 2.1 μm. The results of DFT calculations indicate that the electron transfer happens from S-3p to I-5p orbitals, and both of them demonstrate indirect band gaps. The NLO effects of 1 and 2 are almost fully contributed from the CHI 3 or AsI 3 units. Compared with AgGaS 2, their powder laser damage thresholds are ca. 15 and 51 times higher.