Exploring the Structural and Optical Behavior of a Creatininium p-toluene Sulphonate Single Crystal for Nonlinear Optical Applications

Abstract

In this study, an organic nonlinear optical single crystal, creatininium p-toluene sulphonate (CPTS), is synthesized and grown using slow solvent evaporation in an aqueous medium at ambient conditions. Single-crystal X-ray diffraction demonstrates an orthorhombic structure with non-centrosymmetric space group P2₁2₁2₁. Phase purity and specific (hkl) planes are verified by powder X-ray diffraction, while Fourier-transform infrared spectroscopy identifies functional groups within CPTS. Crystalline integrity of the harvested single crystal is assessed through high-resolution X-ray diffraction techniques. High-resolution X-ray diffraction assessed crystal integrity, and microhardness testing categorized CPTS as a soft material. Growth patterns are investigated using surface etching analysis. UV–vis–NIR absorbance and photoluminescence studies provide optical properties. Third-order nonlinearity studies are performed on a thin, well-cut, and polished single crystal using the Z-scan technique, revealing a nonlinear refractive index of $-6.87\times {10}^{-14}{m}^2/W$ and a nonlinear absorption coefficient of $6.08\times {10}^{-7}m/W$.