Synthesis, nucleation, growth, structural, spectral, thermal, linear and nonlinear optical studies of novel organic NLO crystal: 4-fluoro 4-nitrostilbene (FONS)

A novel organic nonlinear optical material 4-fluoro 4-nitrostilbene (FONS), with molecular formula (C14H10FNO2) has been synthesized. Using ethyl methyl ketone as solvent, the synthesized material has been repeatedly recrystallized to minimize the impurities and good optical quality single crystals were harvested by slow evaporation method. Single crystal X-ray diffraction analysis reveals that the grown FONS crystal belongs to monoclinic system with noncentrosymmetric space group “P21”. The powder X-ray diffraction pattern of FONS has been recorded. Functional groups of the title compound were confirmed by FTIR and the molecular structure was confirmed by 1H NMR. The UV–vis–NIR absorption study reveals no absorption in the visible region and the cut-off wavelength was found to be at 408 nm. Optical band gap (Eg) of the grown crystal was found to be 3.27 eV and also the optical constants were determined. Thermal behaviour of the FONS has been studied by TGA/DTA analyses. From the mass spectrum, the ratio of compound formation of FONS was analyzed. The NLO property has been confirmed by Kurtz and Perry powder SHG technique and the SHG efficiency of FONS (262 mV) crystal was found to be 12 times greater than that of KDP (21.7 mV).

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► A novel organic nonlinear optical material FONS has been synthesized.
► The good optical quality single crystals were grown by slow evaporation method.
► The FONS crystal has a wide transparency in the range of 408–1100 nm.
► Optical band gap (Eg) of the grown crystal is 3.27 eV.
► The PL measurements show that the material is suitable for green light emission.