The exploration of the crystal nucleation parameters and physico-chemical analysis of a single crystal: 2-amino-4,6-dimethoxypyrimidinium hydrogen (2R,3R)-tartrate 2-amino-4,6-dimethoxypyrimidine.

This paper discusses the structural orientations and the physico-chemical properties of a single crystal of 2-amino-4,6-dimethoxypyrimidinium hydrogen (2R,3R)-tartrate 2-amino-4,6-dimethoxypyrimidine (2ADT). The experimental investigation of the properties of the compound improves the potential for the utilization of the crystalline compound in the fabrication of optical limiting and nonlinear optical devices. For the growth process, an organic nonlinear optical crystal of 2ADT is synthesized conventionally at varying molar concentrations to achieve an excellent yield. The structural orientations and refinements of the compound are identified and discussed with reference to a single crystal X-ray diffraction study and its supporting computations. The results of the experimental analysis via UV-vis-NIR spectrometry and a z-scan setup with a laser beam source are used in an in-depth discussion on the linear and nonlinear optical properties of the crystal together with its damage threshold induced by a Nd:YAG laser beam at 1064 nm. With optical transparency of 55% in the entire visible region, a lower cut-off wavelength at 228 nm, and a bandgap at 5.2 eV, the crystal was demonstrated to be suitable for use in optical device fabrication. The thermogravimetrically assessed thermal stability of 2ADT was examined up to 147 °C. In addition, the thermodynamic parameters responsible for activation reactions are also discussed because these give information about the material's thermal behavior. An optical limiting study revealed that the transmitted output power increases linearly with the input power at about 1.89 mW cm-2.

A combined experimental and quantum chemical analysis to explore the nonlinear optical activity of guanidinium L-monohydrogen tartrate.

Single crystal of guanidinium l-monohydrogen tartrate (GuHT) was grown by slow evaporation technique and was characterized by single crystal X-ray diffraction to confirm its crystal structure. UV-vis spectral study reveal that the GuHT crystal is optically transparent and its band gap was estimated from the transmittance data. The laser induced surface damage threshold study was carried out for the grown crystal using Nd:YAG laser. The second harmonic generation (SHG) nonlinearity of the grown crystalline sample was measured by Kurtz and Perry powder technique. The optimized molecular geometry, first order hyperpolarizability, dipole moment and polarizability of GuHT were obtained by density functional theory (DFT) using B3LYP/6-31G (d,p) level of basis set. The thermodynamic functions of the title compound was computed. The HOMO-LUMO energy gap explains the charge transfer interactions that take place within the molecule.

Electronic structure, vibrational spectral and intervening orbital interactions studies of NLO material: guanidinium 4-nitrobenzoate.

Single crystals of guanidinium 4-nitrobenzoate (GPNB) have been grown by slow evaporation method. Grown crystals were characterized by FT-IR, FT-Raman, UV-Vis absorption and UV-Vis transmission spectroscopies. Crystal defects and surface morphology were studied by etching method. Dielectric properties of the crystal such as dielectric constant, dielectric loss and AC electrical conductivity as function of frequency (50 Hz-5 MHz) at two temperatures (35°C and 100°C) were measured. The frequency and temperature dependence of dielectric behaviour were investigated. The equilibrium geometry, vibrational spectral analysis, intramolecular charge transfer interactions using NBO method, first order hyperpolarizability, molecular electrostatic potential and frontier molecular orbital analysis for GPNB have been studied using density functional theory at B3LYP/cc-pVTZ level. Vibrational spectral study reveals the presence of moderate and weak N-H⋯O bonds in GPNB. NBO analysis also confirms the presence of intramolecular N-H⋯O hydrogen bonding and investigates the stability as well as the intervening orbital interactions. The electronic absorption spectrum of the gas and water phases of GPNB were simulated using time dependent density functional theory and NBO transitions for the three lowest excited states were assigned and studied.

Growth, spectral, anisotropic, second and third order nonlinear optical studies on potential nonlinear optical crystal anilinium perchlorate (AP) for NLO device fabrications.

A new semiorganic nonlinear optical material anilinium perchlorate was grown by the slow evaporation technique using water as solvent. The solubility and meta stable zone width were determined. The anilinium perchlorate crystal belongs to orthorhombic system with noncentrosymmetric space group P212121. The presence of various functional groups was identified by FT-IR FT-Raman spectrum. The morphology of the anilinium perchlorate crystal was studied. From this morphology, anilinium perchlorate crystal plate was cut along three prominent planes, such as (001), (010) and (20-1). The thermal stability of the crystal was determined using TG-DTA studies. The hardness, laser damage threshold, transmittance, reflectance, experimental refractive index of the crystal was found. The particle size dependent second harmonic generation efficiency for anilinium perchlorate was evaluated by Kurtz-Perry powder method using Nd:YAG laser, which established the existence of phase matching. The third order nonlinear refractive index and nonlinear absorption coefficient of the grown crystal were measured by Z-scan studies.

Performance of Caesalpinia sappan heartwood extract as photo sensitizer for dye sensitized solar cells.

A natural dye extracted from Caesalpinia sappan heartwood was used as photo sensitizer for the first time to fabricate titanium dioxide (TiO2) nanoparticles based dye sensitized solar cells. Brazilin and brazilein are the major pigments present in the natural dye and their optimized molecular structure were calculated using Density functional theory (DFT) at 6-31G (d) level. The HOMO-LUMO were performed to reveal the energy gap using optimized structure. Pure TiO2 nanoparticles in anatase phase were synthesized by sol-gel technique. The pure and natural dye sensitized TiO2 nanoparticles were subjected to structural, optical, spectral and morphological studies. Low cost and environment friendly dye sensitized solar cells were fabricated using natural dye sensitized TiO2 based photo anode. The solar light to electron conversion efficiency of Caesalpinia sappan heartwood extract sensitized dye sensitized solar cell is 1.1%.

Experimental and theoretical investigations on N,N'-diphenylguanidinium dihydrogen phosphite - a semi-organic nonlinear optical material.

Single crystal of N,N'-diphenylguanidinium dihydrogen phosphite (DPGP) was grown by a slow evaporation technique and was characterized by single crystal X-ray diffraction and powder X-ray diffraction to confirm the structure and crystalline nature of DPGP crystal. UV-vis spectral study revealed that the DPGP crystal is optically transparent. The chemical bonding and presence of various functional groups were confirmed by the FT-IR and FT-Raman spectral studies. The thermal behavior of DPGP crystal was analyzed by simultaneous TG-DTA studies. The laser induced surface damage threshold study was carried out for the grown crystal using Nd:YAG laser. The second harmonic generation (SHG) nonlinearity of the grown crystalline sample was measured by the Kurtz and Perry powder technique. The quantum chemical analyses were performed by density functional theory (DFT) using B3LYP/6-31G (d,p) basis set.

Synthesis, spectral analysis, optical and thermal properties of new organic NLO crystal: N,N'-Diphenylguanidinium Nitrate (DPGN).

A new organic NLO material N,N'-Diphenylguanidinium Nitrate (DPGN) single crystal was grown by slow evaporation technique using methanol as solvent. Single crystal X-ray diffraction and powder X-ray diffraction experiments were carried out in order to confirm the structure and crystalline nature of DPGN crystal. Wide band gap of 3.9eV with transmittance of 57% up to 800nm is observed for the grown crystal using UV-vis spectral analysis. The chemical bonding and presence of various functional groups were confirmed by the FT-IR and FT-Raman spectral studies. The thermal behavior of DPGN crystal was analyzed by simultaneous TG-DTA studies. The second harmonic generation (SHG) nonlinearity of the grown crystal was measured by Kurtz and Perry powder technique and was found to be comparable with that of the standard reference material potassium dihydrogen phosphate (KDP) crystal.

Natural dye extract of lawsonia inermis seed as photo sensitizer for titanium dioxide based dye sensitized solar cells.

Natural dye extract of lawsonia inermis seed were used as photo sensitizer to fabricate titanium dioxide nanoparticles based dye sensitized solar cells. Pure titanium dioxide (TiO2) nanoparticles in anatase phase were synthesized by sol-gel technique and pre dye treated TiO2 nanoparticles were synthesized using modified sol-gel technique by mixing lawsone pigment rich natural dye during the synthesis itself. This pre dye treatment with natural dye has yielded colored TiO2 nanoparticles with uniform adsorption of natural dye, reduced agglomeration, less dye aggregation and improved morphology. The pure and pre dye treated TiO2 nanoparticles were subjected to structural, optical, spectral and morphological studies. Dye sensitized solar cells (DSSC) fabricated using the pre dye treated and pure TiO2 nanoparticles sensitized by natural dye extract of lawsonia inermis seed showed a promising solar light to electron conversion efficiency of 1.47% and 1% respectively. The pre dye treated TiO2 based DSSC showed an improved efficiency of 47% when compared to that of conventional DSSC.

Growth, spectroscopy properties and DFT based PCM calculations of guanidinium chlorochromate.

Nonlinear optical single crystals of guanidinium chlorochromate [GCC] are grown by slow evaporation solution growth technique using water as the solvent. Purity of crystals is increased by the method of recrystallization. The solubility of the material is measured at various temperatures in de-ionized water. The grown crystals are characterized by single crystal XRD for obtaining unit cell parameters. The presence of functional groups and modes of vibrations are identified by FT-IR spectroscopy. The chemical structure of crystal is established by FT-NMR techniques. The UV-vis-NIR spectrum of GCC shows less absorption and good transmittance in the entire visible region enabling its use in optical application. Also, the Kurtz powder second harmonic generation test shows that the compound is a potential material for optical second harmonic generation. The theoretical vibration frequency of HC(NH2)3 and [C(NH2)3]2 are analyzed in different solvent media.

Studies on growth, spectral, optical and mechanical properties of new organic NLO crystal: guanidinium L-glutamate (GuGL).

Good optical quality single crystal of guanidinium l-glutamate is grown by slow evaporation solution growth technique. The cell parameters and crystallinity are determined from the single crystal and powder X-ray diffraction analysis. The formation of synthesized compound was confirmed by FT-IR and FT-Raman spectroscopic analysis. Wide band gap of 4.98eV with high transmittance up to 2000 nm is observed for the grown crystal in UV-Vis-NIR spectral analysis. The optical constants such as refractive index and extinction coefficient of the grown crystal are obtained as 2.1 and 8.64×10(-6) respectively. The nonlinear optical study reveals that the second harmonic generation efficiency of guanidinium l-glutamate is 2.8 times that of potassium dihydrogen phosphate (KDP). The mechanical stability of the grown crystal was analyzed by Vickers microhardness test and the results are discussed.

Synthesis, growth, structural, spectroscopic and optical studies of a semiorganic NLO crystal: zinc guanidinium phosphate.

The semi-organic nonlinear optical (NLO) crystal, zinc guanidinium phosphate (ZGuP) has been grown through synthesis between zinc sulphate, guanidine carbonate and orthophosphoric acid from its aqueous solution by slow solvent evaporation technique. Solubility of the synthesized material has been determined for various temperatures using water as solvent. The grown crystal has been characterized by powder X-ray diffraction to confirm the crystal structure. Investigation has been carried out to assign the vibrational frequencies of the grown crystals by Fourier transform infrared spectroscopy technique. (1)H and (13)C FT-NMR have been recorded to elucidate the molecular structure. The optical absorption study confirms the suitability of the crystal for device applications. The second harmonic generation (SHG) efficiency of ZGuP is found to be 1.825 times that of potassium dihydrogen phosphate (KDP). Thermal behavior of the grown crystals has been studied by thermogravimetric and differential thermal analysis. The mechanical properties of the grown crystals have been studied using Vickers microhardness tester.

Growth, spectral, optical and thermal characterization of new metallorganic crystal--bisthiourea nickel chloride.

The novel nonlinear optical single crystal of bisthiourea nickel chloride (BTNC) was grown successfully by slow evaporation technique using water as solvent. The lattice parameters of the grown crystal have been determined by X-ray diffraction studies. Vibrational spectra were recorded to determine the symmetries of molecular vibrations. Presence of various functional groups of BTNC was identified through FTIR and Raman spectroscopic analyses. Optical absorbance spectrum recorded in the wavelength range of UV-vis-NIR revealed that this crystal has good optical transparency in the range 200-2000 nm. The second harmonic generation test of BTNC revealed the nonlinear nature of the crystal. The BTNC crystal was analyzed by differential thermal and thermo gravimetric analysis (DTA-TGA) to obtain its thermal stability.

Synthesis, growth and characterization of bis (glycine) lithium molybdate--a semi-organic NLO material.

Single crystals of bis (glycine) lithium molybdate [BGLM] with dimensions 20mmx10mmx5mm were grown by slow evaporation technique. The grown crystals were subjected to powder X-ray diffraction studies. Functional groups of the crystallized molecules were confirmed by FTIR analyses. Transmission range of the crystal was determined by UV-vis-NIR spectra. Vickers microhardness test was performed on the prominent plane (011) of the grown crystal. The NLO property of the crystal was confirmed by Kurtz SHG test and compared with NLO efficiency of KDP crystal.