Our earlier theoretical calculation and preliminary experiment highlighted LiZnPS₄ as a good mid-infrared (mid-IR) nonlinear optical (NLO) material. However, this compound suffers from problems including corrosion of the silica tubes, a pungent smell, deliquescence, and incongruent-melting behavior in the further single crystal growth and applications. In order to overcome these problems, herein, we investigate the analogues of LiZnPS₄ and propose that AgZnPS₄ would be a good candidate. The combination of experimental and theoretical study demonstrates that AgZnPS₄ exhibits a much stronger NLO effect than that of LiZnPS₄ despite the relatively smaller energy band gap. More importantly, AgZnPS₄ melts congruently with a melting point as low as 534 °C, much lower than those of traditional IR NLO crystals, and is nondeliquescent with enough stability in the air. Such a good crystal growth habit and chemical stability enable AgZnPS₄ to possess much better overall performance for the practical mid-IR NLO applications. 

Inorg. Chem., Article ASAP

DOI: 10.1021/acs.inorgchem.6b00517

Publication Date (Web): March 25, 2016