부산대학교 도서관

Non-centrosymmetric chalcogenides are attracting considerable attention as highly promising infrared nonlinear optical(IR-NLO)candidates,but it is challenging to simultaneously achieve sufficient second-harmonic-generation coefficient(deff＞0.5×AgGaS2)and large energy gap(Eg＞3.5 eV).In this work,a novel ternary chalcogenide,Cs5Ga9S16 with an ultra-wide Eg of 4.05 eV,has been successfully ob-tained.This sulfide belongs to the monoclinic space group Pn(No.7)with a novel 3D anionic[Ga9S16]5-framework that is formed by super-polyhedral[Ga9S23]units through corner-sharing S atoms.Such a unique crystal structure displays desirable characteristics which indicate a promising IR-NLO candidate:favourable phase-matching feature,sufficient deff(0.7 × AgGaS2),ultrahigh laser-induced damage thresh-old(31.6 × AgGaS2)and broad transparent region(0.27-14.96μm).In addition,systematic theoretical studies and structural analysis suggest that the desirable IR-NLO performances can be attributed to the super-polyhedral building blocks.This finding may provide useful insight into the understanding and de-signing other high-performance IR-NLO candidates with super-polyhedral-built structures.