Mohd Anis, S.S. Hussaini, M.D. Shirsat and G.G. Muley
device applications. As doping can largely influence the characteristic traits of the crystal system, various researchers have re-investigated the ZTC crystal using different amino acids. The positive impact of glycine on structural, UV-Vis, thermal and SHG efficiency of ZTC crystal has been reported in the literature [ 3 ]. The improved structural, linear-nonlinear optical and thermal studies of L-alanine doped ZTC crystal have been explored [ 4 ]. The influence of L-cysteine on optical transparency, SHG efficiency, photoluminescence, thermal and dielectric properties
L-cysteine hydrogen fluoride (LCHF) single crystals were grown from aqueous solution. Single crystal X-ray diffraction, FT-IR, UV-Vis-NIR, and TG-DTA were used to test the grown crystals. The specimen dielectric and mechanical behaviors were also studied. Powder X-ray diffraction of the grown crystal was recorded and indexed. The optical properties of the LCHF crystal were determined using UV-Vis spectroscopy. It was found that the optical band gap of LCHF was 4.8 eV. The crystal functional groups were identified using FT-IR. Second harmonic generation (SHG) efficiency of the LCHF was three times higher than that of KDP. The dielectric constant, dielectric loss and AC conductivity were measured at different frequencies and temperatures.
Single crystal of glycine hydroflruoride (GHF) was grown from aqueous solution by slow evaporation technique. The structure of the grown crystal was tested and analyzed through X-ray powder diffraction. The functional groups have been identified from the FT-IR spectra. Slabs cut normal to the b-axis from the grown crystal were subjected to incident radiation with a wavelength range of 200 nm to 800 nm to investigate the transmittance and reflectance spectra. Linear optical parameters such as extinction coefficient k, refractive index n and both the real and imaginary parts: ∊real and ∊im of the dielectric permittivity were calculated as functions of the incident photon energy. The dispersion of the refractive index was fitted in terms of Cauchy formula and Wemple-DiDomenico single oscillator model. GHF crystals exhibited indirect optical interband transition and the optical energy gap Eg was determined by using Tauc plot. The indirect band gaps at elevated temperatures were determined and their temperature dependence was estimated. Optical band gap Eg values were found to decrease with an increase in crystal temperature; however, the band tail width exhibited opposite behavior. The nonlinear optical potential was examined by the second harmonic generation (SHG) test.
A. Anbarasi, S.M. Ravi Kumar, M. Packiya Raj, G.J. Shanmuga Sundar, M. Ganapathy, T. Kubendiran and S. Varalakshmi
A novel semiorganic nonlinear optical (NLO) crystal, bis(thiourea) barium nitrate (BTBN) was synthesized and grown by slow evaporation method. Structure of the new crystalline compound was confirmed by single crystal X-ray diffraction analysis and it showed that BTBN belongs to orthorhombic crystal system. The crystalline nature of the BTBN was confirmed by powder X-ray diffraction study. Important functional groups of BTBN were identified by FT-IR spectroscopic analysis. UV-Vis-NIR spectral study showed that the grown crystal is transparent in the entire visible region with low cut off wavelength of 304 nm. BTBN exhibits a SHG efficiency which is nearly 2.38 times higher than that of KDP. The BTBN crystal has high mechanical strength and belongs to soft category, which was confirmed by micorhardness study. The thermal stability of BTBN was determined from TGA and DTA thermal study which revealed that the BTBN crystal has thermal stability up to 243.1 °C. The surface properties and presence of elements was analyzed by SEM and EDAX study, respectively.
M.R. Jagadeesh, H .M. Suresh Kumar and R. Ananda Kumari
A new semi-organic non linear optical crystal, L-leucine phthalic acid potassium iodide (LLPPI) has been grown from an aqueous solution by slow evaporation method. The grown crystals were subjected to different characterizations, such as single crystal XRD, FT-IR, UV-Vis, TGA, SEM, EDAX, micro hardness, dielectric and powder SHG. Single crystal structure was determined from X-ray diffraction data and it revealed that the crystal belongs to triclinic system with the space group P1. The vibrational frequencies of various functional groups were derived from FT-IR spectrum. Thermal stability of the grown crystal was investigated by TG-DTA studies and it was observed that the crystal was thermally stable up to 192 °C. Optical absorption study was carried out and a good transparency in the entire visible region was observed at the lower cutoff wavelength of 227 nm. Dielectric study was performed as a function of frequency and normal dielectric behavior was observed. The micro hardness test was carried out and the load dependent hardness was measured. Kurtz powder method was employed to explore the NLO characteristics of the grown crystal.
In the present work, a new organic second order NLO material: L-isoleucinium p-toluenesulfonate monohydrate (LIPT) is synthesized and reported for the first time. The LIPT is crystallized in a non-centrosymmetric monoclinic space group P21. Structural and hydrogen bond nature of the compound is analyzed using single crystal X-ray diffraction studies. The crystal exhibits very good optical properties such as wide optical transparency in the region of 210 nm to 1100 nm and the ultraviolet wavelength emission (λ = 283 nm). The second harmonic generation efficiency is found to be 1.7 times the standard KDP. Good thermal, mechanical properties and low dielectric constant at high frequency range show that the material may be a potential candidate for optoelectronic applications.
L. Chandra, J. Chandrasekaran, K. Perumal, B. Babu and V. Jayaramakrishnan
-aminopyridine. Hence, the asymmetric system consists of a protonated 2-aminopyridine mono-ionized with 4-aminobenzoic acid. Previously, Arumanayagam et al.  performed optical transmittance, band gap, refractive index, optical conductivity, dielectric and powder SHG studies of these crystals. In this manuscript, additionally to those studies, we present the first investigation of the powder XRD, FT-IR, birefringence, photoconductivity, etching and phase matching properties of APAB.
Pure specimens of 2-aminopyridine and 4
A. Arputha Latha, M. Anbuchezhiyan, C. Charles Kanakam and K. Selvarani
to single crystal X-ray diffraction analysis (SXRD) using ENRAF NONIUS CAD4 automatic X-ray diffractometer with MoKα (λ = 0.7170 Å) radiation. The cell parameters of γ-glycine single crystal obtained from SXRD study are as follows, a = 7.02 (12) Å, b = 7.02 (12) Å, c = 5.47 (9) Å, α = β = 90°, γ = 120°, and V = 233 (4) Å 3 . The γ-glycine single crystal belongs to a hexagonal crystal system with noncentrosymmetric space group P3 1 which are the necessary criteria for SHG. These values are found to be in good agreement with the reported data [ 7 ]. The powder X
Single crystals of Y1−xRxCa4O(BO3)3 (R = Sc or Lu) of good quality have been grown from the melt by the Czochralski pulling method. The chemical compositions of the grown crystals were determined. Type-I noncritical phase matching (NCPM) wavelengths for second harmonic generation (SHG) in Y1−xRxCa4O(BO3)3 grown crystals were also determined.
It is important to grow and characterize new bimetallic thiocyanate single crystals as they are expected to exhibit useful optical and electrical properties. In the present study, calcium cadmium thiocyanate CaCd(SCN)4 single crystals were grown by slow evaporation of solvent and were characterized chemically, structurally, thermally, optically and electrically. X-ray diffraction analysis indicates that the grown crystal belongs to the tetragonal crystal system with lattice parameters: a = b = 12.2491(7) Å and c = 15.1012(5) Å. EDAX spectral analysis confirms the expected chemical composition. Thermogravimetric (TG/DTA) measurement implies good thermal stability. Optical (UV-Vis-NIR absorption spectral and SHG efficiency) measurements suggest good optical absorption in the UV and blue regions and the SHG efficiency of 6.13 (in urea unit). The dielectric measurements carried out in the temperature range of 40 °C to 150 °C at five different frequencies, viz. 100 Hz, 1 kHz, 10 kHz, 100 kHz and 1 MHz indicate a normal dielectric behavior.