Crystal structure and nonlinear optical absorption of a new chalcone derivative: a promising candidate for optical switching

A new nonlinear optical material, 4-[(2E)-3-(3-fluorophenyl) prop-2-enoyl] benzonitrile (3FPB), belonging to chalcone family was synthesized and characterized by FTIR and linear absorption spectroscopy. Single-crystal X-ray diffraction reveals that the new material crystallizes in monoclinic system with P2(1)/c space group and lattice parameters a = 6.4841(2) angstrom, b = 13.6038(5) angstrom, c = 14.6418(6) angstrom, alpha = 90.00 degrees, beta = 94.552(2)degrees and gamma = 90 degrees. The crystallographic perfection of the synthesized material has been analyzed by X-ray powder diffraction. The X-ray powder diffraction peaks of the sample were indexed with hkl values. The UV-visible spectrum for 3FPB crystals showed the optical transmittance window and a lower cutoff wavelength of absorption at 343 nm. The direct transition band gap energy and indirect transition energy gap were determined using Tauc's plots. The thermal stability and melting point of the material have been investigated by thermogravimetric analysis/differential thermal analysis (TGA/DTA). The Thermogravimetric curve showed the absence of any phase transition before melting point. Third-order nonlinear absorption and optical limiting experiment were carried out using open-aperture Z-scan experiment with Nd:YAG laser nanosecond pulses at a wavelength of 532 nm.