Li[LiCs2Cl][Ga3S6]: Unprecedented Tetrahedra-built Nanoporous Framework with Excellent Nonlinear Optical Performance.

Abstract

Large nonlinear optical (NLO) coefficient and wide band gap are two crucial but contradictory parameters that are difficult to simultaneously achieve in a single infrared (IR) NLO compound. Here, a new salt-inclusion chalcogenide (SIC), Li[LiCs 2 Cl][Ga 3 S 6 ] ( 1 ), which presents the first nano-sized tunnel framework constructed by monotype chalcogenide tetrahedra, is successfully obtained. Highly oriented covalent GaS 4 tetrahedra in the host lead to moderate second harmonic generation response (0.7×AgGaS 2 ), and ionic guests effectively broaden the band gap to the widest value (4.18 eV) among all IR NLO chalcogenides, thereby achieving remarkable balance between NLO efficiency and band gap.