Bulk Crystal Growth, Optical, Electrical, Thermal, and Third Order NLO Properties of 2-[4-(Diethylamino)benzylidene]malononitrile (DEBM) Single Crystal

摘要

Bulk organic nonlinear optical (NLO) single crystals of DEBM (2-[4-(diethylamino)benzylidene]malononitrile), with sizes up to 22 X 5 X 12 mm(3) have been grown in ethyl acetate solution by the slow evaporation method. The lattice parameters and crystalline purity of the titled crystal were measured by single crystal X-ray diffraction and powder XRD, respectively. The morphology of the grown crystal was portrayed by WinXMorph program. Fourier transform infrared (FT-IR) spectral studies have been performed to identify the functional groups. The molecular structure was confirmed through H-1 NMR. UV-vis-NIR spectral analysis signifies that the DEBM crystal is transparent in entire visible and near-infrared region, which has a lower cutoff wavelength around 476.8 nm. The optical band gap (E-g) was estimated from the Tauc plot and was found to be about 2.68 eV. The low value of the dielectric constant (epsilon(r)) of DEBM suggests that it has a possible strategy toward the microelectronics industry. Thermal stability and melting point (137.8 degrees C) were studied with TGA-DSC analysis. The laser induced damage threshold (LDT) experiments showed that the grown DEBM bulk crystal possess an excellent resistance to laser radiation with a high threshold up to 1.95 GW cm(-2), it is still better compared to other organic and inorganic NLO materials. The third-order optical nonlinearities of the DEBM crystal was confirmed by the single beam Z-scan technique. All these results demonstrate that the organic crystal DEBM is promising for NLO applications.