M. Krishna Kumar

Synthesis, crystal growth, structural, thermal, optical and mechanical properties of solution grown 4-methylpyridinium 4-hydroxybenzoate single crystal

Organic nonlinear optical material, 4-methylpyridinium 4-hydroxybenzoate (4MPHB) was synthesized and single crystal was grown by slow evaporation solution growth method. Single crystal and powder X-ray diffraction analyses confirm the structure and crystalline perfection of 4MPHB crystal. Infrared, Raman and NMR spectroscopy techniques were used to elucidate the functional groups present in the compound. TG-DTA analysis was carried out in nitrogen atmosphere to study the decomposition stages, endothermic and exothermic reactions. UV-visible and Photoluminescence spectra were recorded for the grown crystal to estimate the transmittance and band gap energy respectively. Linear refractive index, birefringence, and SHG efficiency of the grown crystal were studied. Laser induced surface damage threshold and mechanical properties of grown crystal were studied to assess the suitability of the grown crystals for device applications.

Studies on the growth, structural, spectral and third-order nonlinear optical properties of ammonium 3-carboxy-4-hydroxy benzenesulfonate monohydrate single crystal.

An organic nonlinear optical bulk single crystal, Ammonium 3-carboxy-4-hydroxy benzenesulfonate monohydrate (ACHBS) was successfully grown by solution growth technique. Single crystal X-ray diffraction study confirms that, the grown crystal belongs to P21/c space group. Powder X-ray diffraction and high resolution X-ray diffraction analyses revealed the crystallinity of the grown crystal. Infrared spectral analysis showed the vibrational behavior of chemical bonds and its functional groups. The thermal stability and decomposition stages of the grown crystal were studied by TG-DTA analysis. UV-Visible transmittance studies showed the transparency region and cut-off wavelength of the grown crystal. The third-order nonlinear optical susceptibility of the grown crystal was estimated by Z-scan technique using He-Ne laser source. The mechanical property of the grown crystal was studied by using Vickers microhardness test.

Studies on Structural, Spectral, and Optical Properties of Organic Nonlinear Optical Single Crystal: 2-Amino-4,6-dimethylpyrimidinium p-Hydroxybenzoate

2-Amino-4,6-dimethylpyrimidinium p-hydroxybenzoate (ADPHB), a novel organic material, was synthesized, and crystals were grown by slow evaporation solution growth method. The cell parameters and crystalline perfection of the grown crystal were studied by single crystal and powder X-ray diffraction analyses. The presence of various functional groups of the grown crystal was confirmed using Fourier Transform infrared spectral analysis. UV-Visible spectrum shows that ADPHB crystals have high transmittance in the range 305–900 nm. The refractive index and transient photoluminescence properties of the grown crystal were analyzed. The laser induced surface damage threshold, optical birefringence, and second harmonic generation efficiency of the grown crystal were studied.

Studies on the growth, spectral, structural, electrical, optical and mechanical properties of Uronium 3-carboxy-4-hydroxybenzenesulfonate single crystal for third-order nonlinear optical applications

Organic Uronium 3-carboxy-4-hydroxybenzenesulfonate (UCHBS) nonlinear optical single crystal was grown by solution growth technique. The solubility and nucleation studies were performed for UCHBS at different temperatures 30, 35, 40, 45, 50 and 55°C. The crystal structure of UCHBS was elucidated from single crystal X-ray diffraction study. High resolution X-ray diffraction technique was employed to study the perfection and internal defects of UCHBS crystal. Infrared and Raman spectra were recorded to analyze the vibrational behavior of chemical bonds and its functional groups. The physico-chemical changes, stability and decomposition stages of the UCHBS compound were established by TG-DTA studies. The dielectric phenomenon of UCHBS crystal was studied at different temperatures with respect to frequency. Linear optical properties of transmittance, cut-off wavelength, band gap of UCHBS were found from UV-visible spectral studies. Third-order nonlinear optical susceptibility, nonlinear refractive index, nonlinear optical absorption coefficient values were measured by Z-scan technique. The mechanical properties of UCHBS crystal was studied by using Vickers microhardness test. The growth features of UCHBS crystal were analyzed from etching studies.

Al{sup 3+} doped V{sub 2}O{sub 5} nanostructure: Synthesis and structural, morphological and optical characterization

AlxV2-xO5(x = 0,2mol%) nanorods were synthesized at room temperature by facile surfactant free non-aqueous route. The phase pure orthorhombic structure and nanorods-like morphology have been studied by X-ray diffraction (XRD) and High resolution scanning electron microscopy. EDXS spectrum confirms the purity and presence of Al into V2O5 lattice. Optical absorption from DRS UV-Vis spectra showed the band gap broadening due to quantum confinement effect. The results ensure that the dopant cation (Al3+) successfully intercalated with the host cation (V5+) and the products are promising for electrochromic and catalytic applications.

STUDIES ON THE GROWTH, SPECTRAL, OPTICAL AND THERMAL PROPERTIES OF 4-NITROANILINE PICRATE SINGLE CRYSTALS

In this paper, an organic 4-nitroaniline picrate (4NP) single crystal was grown by solution growth method. Single crystal X-ray diffraction study revealed that grown crystal belongs to orthorhombic system with Pbcn space group. The solid state constants such as plasma energy, Penn gap, Fermi energy and polarizability of 4NP crystal were determined theoretically. The functional groups of the grown crystals were confirmed qualitatively from FTIR spectral analysis. The thermal decomposition and melting point of the crystal were determined from thermogravimetric analysis. The optical absorption and cut-off wavelength of the crystal were determined from UV-visible study. The second harmonic generation (SHG) efficiency of the grown crystal was measured by Kurtz–Perry SHG test using Nd:YAG laser. The laser damage threshold value of the grown crystal was estimated by multi-shot method using 1064 nm laser.

Investigation on Rare Earth Doped Nonlinear Optical Potassium Hydrogen Phthalate (KHP) Single Crystals

Rare earth doped potassium hydrogen phthalate (KHP) single crystals have been grown by slow evaporation technique. Single and powder X-ray diffraction analysis confirms the structural and crystallinity of grown crystals. The functional groups of pure and doped KAP crystals have been identified by FTIR spectral studies. UV-Vis studies explore the optical transmittance of the grown crystals in the entire visible region. Nonlinear optical property of the pure and doped KHP crystals was confirmed by Kurtz-Perry powder test.

Investigation on growth, optical and thermal properties of stilbazolium derivative crystal: 4-N,N-dimethylamino-4′-N′-methylstilbazolium 2,4-dimethylbenzenesulfonate

Abstract Metathesis ionic exchange reaction process was used to synthesize a novel nonlinear optical material: 4-N,N-dimethylamino-4′- N′-methylstilbazolium 2,4-dimethylbenzenesulfonate (DSDMS). The growth of DSDMS single crystals was carried out by adopting the solution growth technique. The crystal perfection and lattice parameters were elucidated from single XRD and powder XRD, respectively and its morphology was interpreted by WinXMorph program. FT-IR and Raman spectral analyses confirmed the existence of functional groups and their corresponding vibrational modes. UV-Vis spectral studies revealed the optical transmission region. Mechanical stability of the crystal was determined from Vickers microhardness number Hv, Meyer’s index n and elastic stiffness constant C11. Dielectric and thermal behavior of the grown crystal were elucidated by using impedance analyser and thermogravimetric analysis.

Crystalline perfection, birefringence and laser damage threshold properties of piperidinium p-hydroxybenzoate

Piperidinium p-hydroxybenzoate (PPHB) crystal was grown by slow evaporation method. Single crystal X-ray diffraction studies confirm that PPHB crystallizes in monoclinic crystal system with noncentrosymmetric space group Cc. The crystalline perfection of the grown crystal was evaluated by using high resolution X-ray diffractometry. UV-Visible transmission and birefringence studies were employed on the grown PPHB crystal. The laser induced damage threshold value was estimated using Nd:YAG laser. Thermal behavior of PPHB crystal has been investigated by TG-DTA analyses. Etching studies have been performed to assess the growth pattern of PPHB crystal.

Growth and electrical properties on NLO crystal: 4-N,N-dimethylamino 4′-N′-methylstilbazolium iodide

4-N,N-Dimethylamino-4′-N′-methylstilbazolium tosylate single crystals were grown by solution crystal growth method. The cell parameters of grown crystal have been estimated using single crystal-X-ray diffraction analysis. The variation of real (e) and imaginary (e) part of dielectric constants and dielectric loss were observed for different frequencies and temperatures. The ac and dc electrical conductivities and activation energy were determined for DMSI crystal using dielectric studies.