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The 4-N,N-dimethylamino-4-N-methyl stilbazolium tosylate (DAST) crystal with large size and nearly square shape was grown in high concentration solution by slope nucleation method coupled slow cooling (SNM-SC). Striations considered as planar defects were found on the (0 0 1) face along a -axis in the crystal by optical microscope. Some of the striations were continuous while some of them were discontinuous. In addition, the striations were found on (2 3 1) diffracting face and such lines did not occur on the (3-21) and (−2 2 1) planes. The surface distribution and morphological structure of the crystal were characterized by XRD and atomic force microscope (AFM). The presence of striations in the sample was also confirmed by white-beam synchrotron radiation topography (WBSRT). The mechanism of striations formation was also discussed. [ABSTRACT FROM AUTHOR]

• A new chalcone-based crystal BBC was designed and synthesized. • BBC crystal exhibits a SHG response 14 times larger than that of KDP. • The introduction of Br group, which contributes to strong halogen bond formation, lead to the "head-to-tail" arrangement. A new chalcone-based nonlinear optical crystal BBC (C 22 H 17 BrO 2) using long π-conjugated and halogen substituent, as a potential alternative to develop organic crystals, are reported. BBC was designed and synthesized by replacing benzyloxy and -Br groups on both sides of molecular framework. Flaky yellowish BBC single crystal with size of 5 × 5 × 1 mm3 was grown by solution evaporation method. BBC crystal crystallizes in the monoclinic system, P c (NO. 7) space group, with noncentrosymmetric structure. In the BBC molecule, benzyl oxide acts as donor (D) and Br and carbonyl group act as acceptor (A), forming D - π - A - π - A structure with electron gradient. The introduction of Br group, which contributes to strong halogen bond formation, lead to the "head-to-tail" arrangement. Remarkably, BBC exhibits strong second harmonic generation (SHG) intensity (14 × KDP and 2.2 × Urea), wide transmission range (600-1600 nm, >60%), high optical energy gap (E g =2.85 eV) and high thermal stability (T m =106 °C). In addition, to investigate the relationships between the structure and physical properties, the electronic structure and optical properties of BBC crystal were theoretically calculated. This work not only provides a newly chalcone-based NLO crystal, but also presents a feasible molecular design approach by introducing long π-conjugated and halogen substituents. [Display omitted] [ABSTRACT FROM AUTHOR]

A new NLO chalcone crystal 1-(2-furyl)-3-(4-methylthio phenyl)-2-propen-1-one (FTMS) was successfully designed and the crystal was grown by slow evaporation solution growth technique. The cell data and structure refinement were determined from the single crystal X-ray diffraction. It was found that the SHG efficiency intensity of FTMS was 18 times that of KDP. The thermal decomposition temperature of FTMS was observed at 235 ℃. The crystal has a high transmittance (95%) in 500–2000 nm with a cutoff wavelength of 405 nm. [ABSTRACT FROM AUTHOR]

• EBC single crystal was successfully obtained by slow cooling method in methanol solution. • The SHG efficiency of EBC was 19 times that of KDP crystal. • The optical transmittance of EBC single crystal was 60% in the range of 500–1580 nm. • The thermal stability of EBC crystal is thermally stable at its melting point 129.63 °C. • TD-DFT calculation and Hirshfeld surface receal the intermolecular interaction. Theoretical calculation and characterization on the D-π-A-π-D type of organic nonlinear optical crystals 1-(4-Bromophenyl)-3-(4-ethoxyphenyl)-prop-2-en-1-one (EBC) were studied. The EBC single crystals with a size of 8 × 2 × 2 mm3 were successfully grown using slow cooling method in the methanol solution. Quantum chemical calculations for the experimental structure of the EBC molecule were performed at B3LYP/6-31G basis set using the density functional theory. The powder XRD, FT-IR and 1H NMR spectral of EBC molecule were investigated theoretically and experimentally, which can specify the used enantiopure starting materials, suggest the absence of impurity. The EBC crystals exhibit a large macroscopic nonlinearity, and it is revealed that the second harmonic generation efficiency (SHG) is 20 times that of KDP. Their thermal stability, UN-Vis-NIR spectrum, and the relationship between dielectric properties at different frequencies and temperature had also been investigated. In addition, the molecular electrostatic potential, frontier molecular orbitals, global reactivity descriptors, natural bond orbital, Hirshfeld surface and 2D-fingerprint were analyzed to get a better understanding of the molecular properties. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel ionic organic nonlinear optical crystal 2-(3,4-dimethoxystyryl)- 3-methylbenzothiazolium-4-methylbenzenesulfonate (DOBT) was developed and synthesized, and in methanol solution by slow cooling method to get high quality crystals. • The internal structure and force of the molecule were analyzed in detail, and pictures of the stacking diagram of crystals and the structure of single cells were drawn. • The optical, electrical and thermal properties of the crystal have been tested, which fully proves that the DOBT crystal is an electro-optic crystal with a concentration of development potential. A novel ionic organic nonlinear optical crystal 2-(3,4-dimethoxystyryl)- 3-methylbenzothiazolium-4-methylbenzenesulfonate (DOBT) was synthesized and grown by slow cooling method. Single crystal X-ray diffraction was used to determine the composition and structure of the crystal. Through the corrosion morphology of the crystal surface, the growth mechanism of the crystal is explored. The surface diagram of molecular electrostatic potential and HOMO-LUMO orbital diagram were calculated and drawn, and the molecular interaction and charge transfer in the crystal were determined. DOBT crystals exhibit a strong second-order nonlinear signal, and the measured SHG signal intensity of the crystal raw material powder is about 6 times that of KDP. The PL spectrum, UV–Vis-NIR spectrum and dielectric diagram of the crystal were analyzed, which proved that the DOBT crystal has superior photoelectric properties. [Display omitted] [ABSTRACT FROM AUTHOR]

1-(4-methoxyphenyl)-3-(3,4-dimethoxyphenyl)-2-propen-1-one(DMMC), a chalcone derivative was synthesized by Claisen-Schmidt condensation reaction method. The growth of DMMC in methanol was used the slow evaporation technique. Single crystal X-ray diffraction revealed that the space group of DMMC is P2 1. The intermolecular interaction of crystal was analyzed by Hirshfeld surface. The second harmonic generation efficiency of DMMC was measured by Kurtz-Perry powder method. When the particle size was between 250 and 300 μm, the SHG efficiency of DMMC was the largest, which was about 60 times that of the KDP with the same particle size. All functional groups of the crystal were identified by FT-IR and 1H NMR spectral. This crystal had a wide transmission range in the region of 350−2000 nm with the cut off wavelength is 400 nm. The thermal properties of the sample were tested, and the melting point was at 95.59 °C. The dielectric constant of the compounds was found to be 17 below 45 °C. [ABSTRACT FROM AUTHOR]

Research progress of an organic second-order nonlinear optical crystal 2-(4-(dimethylamino)styryl)-benzothiazole (DMASBT) was grown with slow cooling method and its performance characterization in different aspects were reported. It was found that the crystals had a high second harmonic generation efficiency of 9.8 times higher than that of KDP crystal. Crystal structure of the crystal was investigated by single crystal XRD. It was found that the crystal lattice is monoclinic. In addition, the crystal growth mechanism and intermolecular interaction were analyzed by chemical etching and Hirshfeld surface. The functional groups of the raw materials were determined by FT-IR, Raman, 1H NMR and elemental analysis. UV–vis–NIR spectrum, dielectric properties under different frequencies, thermal stability, and photostability of the crystal in powder state were also studied. • The highlights of this manuscript are shown as follows: • DMASBT crystal with sizes of 5 × 2 × 1 mm3 was prepared for the first time. • DMASBT has high second harmonic generation efficiency of 9.8 times that of KDP. • The dielectric properties of the DMASBT crystal are studied for the first time. [ABSTRACT FROM AUTHOR]