A infrared (IR) nonlinear optical (NLO) material Ag3Ga3SiSe8 has been synthesized for the first time. It crystallizes in the tetragonal chalcopyrite AgGaSe2 structure type and the substitution of Ga3+ by Si4+ generates equal amount of vacancy at the Ag+ position.Ag3Ga3SiSe8 is a congruent melting compound with the melt temperature of 784℃. The second-harmonic generation (SHG) effect of Ag3Ga3SiSe8 is close to that of AgGaSe2, as confirmed by the first-principles studies. Moreover, the diffuse reflectance spectra reveal that the energy band gap of Ag3Ga3SiSe is 2.30 eV, 0.44 eV larger compared with AgGaSe2 (1.86 eV). The birefringence of Ag3Ga3SiSe8 is predicted to be about 0.1 at the wavelength of 1 μm, significantly larger than that of AgGaSe2 (Δn ~ 0.02), Our results indicate that Ag3Ga3SiSe8 may possess improved optical properties compared with AgGaSe2 and is promising for application as a good IR NLO material.

CrystEngComm,2014