Effect of additives on the large-size growth of 4-N,N-dimethylamino-4-N-methyl stilbazolium naphthalene-2-sulfonate (DSNS) single crystal: an efficient stilbazolium derivative NLO crystal with potential terahertz wave properties.

Abstract

We explored the growth of the highly nonlinear optical stilbazolium salt 4-N,N-dimethylamino-4-N-methyl stilbazolium naphthalene-2-sulfonate (DSNS) by a slow evaporation method. The grown crystals are large size and exhibit the good optical quality. The harvested crystals, having suitable dimensions of ~5 mm × 3 mm and thickness in the range of 0.2–0.5 mm², were formed when the anionic additives STPB (sodium tetraphenylborate) and DTPA (diethylenetriamine pentaacetic acid anion) were introduced into the pure DSNS solution and are reported for the first time. The grown crystals are highly suitable for fabrication of photonic devices and waveguiding applications. Through recrystallization of DSNS using various mixed solvents and under different conditions, we obtained different crystalline phases. The grown crystals were subjected to single-crystal X-ray diffraction analysis to confirm the cell parameters and the crystallinity was examined by powder X-ray diffraction analysis. The various modes of functional groups present in the synthesized compound were confirmed by FT-IR and NMR spectral analysis. The transparency range was analyzed by UV-vis-NIR spectral studies. The TGA/DTA analysis reveals that the crystal is stable up to 300.2 °C.