Synthesis, structure and characterization of new promising organic NLO crystal: thiosemicarbazide 4-hydroxybenzenesulfonate monohydrate (THBSM)

Abstract

A new organic non-linear optical (NLO) single crystal of thiosemicarbazide-4-hydroxybenzenesulfonate Monohydrate (THBSM) was successfully synthesized and single crystals were grown by slow evaporation solution growth technique (SESGT). The single crystal X-ray diffraction studies confirm that the grown crystal crystallizes in monoclinic system with P21/n space group. The asymmetric part of the title crystal contains isolated thiosemicarbazide cation, 4-hydroxybenzesulfonate anion and a water molecule. Thereby, interplay between vast number of intermolecular interactions such as N–H⋯S, N–H⋯O, C–H⋯O, O–H⋯O and O–H⋯S hydrogen bonds are taken for discussion. FT-IR spectral analysis showed the vibrational behaviour of chemical bonds and presence of its functional groups. UV–Vis–NIR spectral analysis reveals that the optical transparency of THBSM is more than 90% in the entire Vis–NIR region, which confirms its colourless nature and suitable candidate for applications in optoelectronic devices. Photoluminescence (PL) spectrum exhibits a sharp and broad emission peak at centered at 415 nm indicates violet emission. Thermal stability and melting point of the titular compound were studied by TG-DSC analysis. The low value of the dielectric constant of THBSM suggests that the crystal can be used in the microelectronics industry. Third-order nonlinear optical parameters of the title crystal were studied by the single beam Z-scan technique at 632.8 nm using a He–Ne laser as a source. Moreover it exhibits strong reverse saturable absorption (RSA) and a self-focusing nature with large second-order hyperpolarizability (γ = 7.304×10−34 esu), which are mainly associated with electronic processes. From the analyzed results, it is clear that the title crystal possesses excellent third-order nonlinear optical (TONLO) properties and it is suitable for all optical switching, optical limiting and photonic applications.