Facile syntheses of silver thioantimonates exhibiting second-harmonic generation responses and large birefringence

Abstract

Two chalcogenide crystalline compounds, [enH ][Ag Sb S ] (en = ethylenediamine) and [enH][Ag SbS ], have been successfully synthesized by mild ionothermal and solvothermal means. [enH][Ag SbS ] crystallizes in the noncentrosymmetric (NCS) and polar space groupPc, and its linear and nonlinear optical (NLO) properties have been investigated for the first time. Second harmonic generation (SHG) measurements revealed that [enH][Ag SbS ] affords powder SHG performance values of 2.5 × KDP @1064 nm and 0.2 × AgGaS @2100 nm. Additional particle sizevs.SHG efficiency measurements indicate that [enH][Ag SbS ] is phase-matchable. The calculated birefringence Δnis 0.177 at 1064 nm, which is sufficiently large (the largest value among NCS thioantimonates) to achieve phase matching. [enH ][Ag Sb S ] crystallizes in the centrosymmetric space groupP2 /cand its structure features a double-layered variant honeycomb-like anionic network parallel to theacplane separated by [enH ] cations. The optical band gaps of [enH ][Ag Sb S ] and [enH][Ag SbS ] are found to be 2.37 and 2.53 eV, respectively. Theoretical studies using density functional theory have been implemented to further elucidate the relationship between the band structure and NLO properties in [enH][Ag SbS ].