S.Kalainathan
VIT University, India
Title: Structural and optical properties of 2-[2-(2,4-Dimethoxy-phenyl)-vinyl]-1-ethyl-pyridinium iodide (DBSI) and 1-Ethyl -2-[2-(4-hydroxy-phenyl)-vinyl]- pyridinium iodide (HSPI)
Biography
Biography: S.Kalainathan
Abstract
The search and design of highly efficient organic nonlinear optical (NLO) single crystals are extremely important for the present day technological requirements. We present two D-π-A organic core structures leading to highly efficient nonlinear optical (NLO) single crystals, 2-[2-(2,4-Dimethoxy-phenyl)-vinyl]-1-ethyl-pyridinium iodide (DBSI) and 1-Ethyl -2-[2-(4-hydroxy-phenyl)-vinyl]- pyridinium iodide (HSPI). Single crystals of the above two materials were successfully obtained from the methanol-acetonitrile mixed solvent by slow evaporation method. Single crystal X-ray diffraction analysis revealed that both the crystals crystallized in centrosymmetric crystal system with a triclinic space group Pī and monoclinic space group C2/c. Theoretical calculations were performed to derive HOMO-LUMO energies and dipole moment by using Sparton’14 V1.0.1 program. The actual composition and the expected functional groups have been identified by 1H NMR and FTIR analysis. The optical transmittance window and band gap were ascertained by UV- Visible -NIR studies. Thermal studies exhibited that the grown crystals were thermally stable up to 232.5oC and 226.6oC. The surface features of the grown crystal were assessed by using an optical microscope. The dielectric studies were performed. Laser-induced surface damage and mechanical stability of grown crystal were studied to explore its suitability towards device fabrications. The third-order nonlinear optical susceptibility was derived from Z-scan technique, and it was found to be 1.020 x 10-3 esu (DBSI) and 4.40 x10-4 esu (HSPI) respectively, which is appreciably higher than some reported stilbazolium derivatives. All these obtained results in the present work making it an attractive candidate for NLO applications such as electro-optics and THz-wave generation.