Synthesis and nonlinear optical properties of new gallium thiophosphate Rb2Ga2P2S9

Abstract

A new sulfide, Rb₂Ga₂P₂S₉ (1), crystalized in the polar space group of Pmn2₁, has been successfully synthesized by the high-temperature flux method. Its structural framework is constructed from [Ga₂P₂S₉]²⁻ chains which are separated by Rb⁺ cations. The compound features a wide bandgap of 3.30 eV, and a laser induced-damage threshold 7 times higher than that of the benchmark AgGaS₂ (AGS). Simultaneously, it exhibits a medium second-harmonic-generation intensity: 1.3 times that of KH₂PO₄, and 10% that of AGS, for incident laser radiation at 1064 and 2050 nm, respectively. In addition, a comprehensive investigation of the electronic band structure and optical properties of the material, based on electronic structural calculations, is also demonstrated in this paper.