Chemical Etching Analysis Research Articles

Experimental and theoretical investigation on the SR method grown semi-organic Piperazinium Tetrachlorozincate Monohydrate (PTZM) single crystal for optoelectronic applications

Efficient semi organic nonlinear optical (NLO) Piperazinium Tetrachlorozincate monohydrate (PTZM) [C4H12N2][ZnCL4]·H2O single crystals have been grown by slow evaporation solution technique (SEST) and Sankaranarayanan-Ramasamy (SR) method using water as solvent. Single crystal X-ray diffraction (SXRD) analysis reveals the unit cell parameters of the grown crystal. The morphology of the grown crystal was identified by the single crystal XRD analysis. The electrical properties, dielectric constant, dielectric loss and piezoelectric (d33) coefficient were determined. The etch pit density of PTZM crystal has been calculated by using the chemical etching analysis. The laser damage threshold (LDT) analysis was investigated by Nd: YAG laser and the wavelength of laser is 1064 nm. The mechanical stability of the grown PTZM crystal was studied using Vickers microhardness measurement. Utilizing quantum chemical calculations, the PTZM compound is analyzed for vibrational properties, HOMO and LUMO characteristics, NBO interactions, and the determination of first-order hyperpolarizability. The nonlinear susceptibility and first-order hyperpolarizability results provide compelling evidence and affirm the PTZM molecule’s potential as a strong candidate for nonlinear optical (NLO) applications.

Synthesis, crystal growth and characterization of organic 1,2,4-triazole p-nitrophthalic acid (TPNP) single crystal for nonlinear optical (NLO) applications

The novel organic NLO single crystal 1,2,4-Triazole 4-nitrophthalic acid (TPNP) has been synthesised with methanol as a solvent in an equimolar ratio (1:1) by slow evaporation solution technique (SEST). The grown material was characterized for its NLO applications and reported for the first time. TPNP single crystal with the dimension of 10 mm × 5 mm × 4 mm was grown. The grown crystal was analysed through various characterization studies such as structural, optical, thermal, electrical and third harmonic generation (Z-scan) studies. The structural confirmation of the grown TPNP crystals was investigated by Single Crystal X-ray diffraction (SXRD) analysis. The Powder X-ray diffraction (PXRD) was used to identify the (h k l) planes for the purpose of drawing the morphology diagram of the original crystal image. The optical analysis carried out using UV–Vis-NIR study on TPNP crystal showed good optical transparency (80 %) and it can be used for various optical applications. To identify the structure and the functional groups, Fourier transform infrared (FTIR) study was conducted. Thermogravimetric and differential thermal analysis (TG-DTA) revealed the thermal stability of the grown TPNP crystal upto 155 °C. The surface etch pit density of TPNP crystal was carried out using chemical etching analysis. The negative photoconductive nature of title crystal was identified by photoconductivity analysis. The dielectric permittivity and dielectric loss as a function of frequency were measured for grown crystal. Intermolecular interactions and fingerprint plots of TPNP molecules are executed by Hirshfeld surface analysis. LDT of the title crystal was investigated by Q-switched Nd: YAG laser of wavelength 532 nm. Third order NLO parameters and susceptibility were determined using the Z-scan technique. It is concluded that the material can be effectively employed for various optoelectronic and photonic applications.

Synthesis, crystal growth, optical, thermal, electrical and theoretical investigation on 1,2,3- benzotriazole 2-chloro 4-nitrobenzoic acid (BCNB) single crystal for nonlinear optical (NLO) applications

The 1,2,3-benzotriazole 2-chloro-4-nitrobenzoic acid (BCNB) single crystal was successfully grown by the slow evaporation solution technique (SEST) and using methanol as the solvent for nonlinear optical applications. The crystal system and space group of the BCNB single crystal were identified by single crystal X-ray diffraction (SXRD) analysis. The BCNB crystal was subjected to powder X-ray diffraction (PXRD) to endorse the crystalline quality of the material. The UV–Visible-NIR study exposes the transparency and cut-off wavelength of the BCNB crystal. The chemical environment of carbon and hydrogen in the proposed structure of BCNB crystal was confirmed by FT-NMR studies. The vibrational assignments and their functional groups were identified from the FT-IR and FT-Raman analysis. The thermal properties like thermal stability point, melting point, and decomposing point were examined by Thermogravimetry/Differential thermal analysis (TG-DTA). The third order NLO behaviour of BCNB crystal was investigated by the Z-scan technique. The negative photoconductive nature of BCNB crystal was confirmed by photoconductivity analysis. The surface morphology of the grown crystal was examined by chemical etching analysis. The dielectric experiment (constant & loss) was performed on BCNB crystal as a function of frequency at room temperature to measure electrical properties of the material. Density functional theory (DFT) calculations have been investigated by DFT/B3LYP/6–311++G (d,p) method. To understand the intermolecular interaction of crystal packing, the BCNB material was investigated by Hirshfeld surface analysis and it was concluded that the molecular H-H interactions are of higher value compared to other interactions of the total molecules. The Gaussian 09 W programme was used for the DFT calculations such as molecule structure optimization, natural bond orbital analysis (NBO) and HOMO-LUMO analysis. The HOMO and LUMO energy values are estimated as −7.3239 eV and −2.8958 eV respectively.

Investigation on growth, crystal structure, third-order optical nonlinearity properties and DFT computational studies of novel proton transfer 3-aminopyridine P-nitrobenzoate P-nitrobenzoic acid (3APPNB) single crystal for third-order NLO applications

A new organic single crystal of 3-aminopyridine p-nitrobenzoate p-nitrobenzoic acid (3APPNB) with a size of 8 × 4 × 2 mm3 was grown by slow evaporation solution growth technique at room temperature using methanol solvent. The lattice parameter values were evaluated with the help of single crystal XRD and it confirms that the 3APPNB crystal belongs to triclinic crystal structure and the space group P-1. Crystal unit cell parameters are a = 9.3384(5) Å, b = 10.0403(5) Å, c = 11.094(6) Å, α = 109.4940(10)°, β = 93.964(2)°, γ = 99.890(2)° and V = 957.03 (9) (Å3) were determined. The 3APPNB crystal crystallizes in a centrosymmetric nature, triclinic system and space group P-1. SCXRD study shows that both the anion and the cation are interlinked to each other by two types of symmetrical intermolecular C–H…O and N–H···O hydrogen bonds. The crystalline nature and hkl phases have been determined using Powder XRD studies. The presence of different vibrational groups in the 3APPNB compound is examined by employing Fourier transform infrared (FT-IR) spectral analysis. UV–Vis-DRS spectral analysis signifies that the 3APPNB has a wide transmittance (98 %) and a cut-off wavelength of around 317 nm. The etch pit density (EDP) of 3APPNB crystal was examined by a chemical etching analysis. The thermal studies expose that 3APPNB is thermally stable up to 172 °C. The surface morphology of the 3APPNB is analyzed by SEM. The nonlinear properties like β, n2 and χ(3) were measured through the Z-scan analysis and the values were calculated to be 5.78 × 10−5 m/W, 8.05 × 10−12 m2/W) and χ(3) = 8.936 × 10−9. The third-order nonlinear optical (TONLO) χ(3) values are higher. The achieved TONLO χ(3) value when compared to other similar constituents is owing to the tarnish movement of π-electron configuration from the donor to an acceptor that makes the molecules highly polarized. The results reveal that the 3APPNB crystal finds applications in devices like optical switching and optical limiting. The quantum-chemical theoretical analyses are performed to measure the intrinsic properties of the 3APPNB molecules using DFT calculation. The band gap, orbital energy and second hyperpolarizability are also studied using changing the applied field. Furthermore, Quantum chemical calculations are used to obtain the MESP, HOMO-LUMO and first-order hyperpolarizability for the 3APPNB compound.

Synthesis, crystal growth and characterization of piperazinium 5-nitrosalicylate (P5NS) single crystal for nonlinear optical (NLO) applications

A single crystal of Piperazinium 5-nitrosalicylate (P5NS) was grown by using slow evaporation solution technique (SEST). The structural analysis (crystal system & cell parameter) of the grown P5NS crystal was examined by single crystal XRD and it exposed that the P5NS crystal has a crystal triclinic system and space group (P-1). Using powder XRD analysis, miller index and (h k l) planes were identified. The P5NS crystal has a sharp cutoff wavelength around 380 nm and is transparent in UV region. The FTIR analysis was investigated on the P5NS crystal to find out the P5NS functional groups. The thermogravimetric and differential thermal analysis illustrate that the P5NS crystal is thermally stable upto 255 °C. Further increase in the temperature resulted in decomposition of P5NS. The etch pit density of P5NS crystal has been calculated by using the chemical etching analysis. The Photoconductivity study reveals that the grown PMC crystal has positive photoconductive nature. The electrical properties, dielectric constant and dielectric loss were determined. The laser damage threshold (LDT) analysis was investigated by Nd: YAG laser and the wavelength of laser is 1064 nm. Intermolecular interactions of P5NS is executed by the Hirshfeld surface analysis. The NLO susceptibility (χ(3)) was calculated by the Z-scan method using the source of He-Ne laser, whose wavelength is 632.8 nm.

A New Non-linear Stilbazolium Derivative Crystal of 4-[2-(3 Methoxy-phenyl)-vinyl]-1-methyl-pyridinium+ Iodide− (MMPI): Analysis of Its Structural, Surface, Optical and NLO Properties

New organic stilbazolium family of 4-[2-(3 methoxy-phenyl)-vinyl]-1-methyl-pyridinium+ iodide− (MMPI) was successfully synthesized using the condensation reaction method. The recrystallization process was carried out to improve the purity of the synthesized material, and MMPI and grown into a single crystal by the solvent evaporation method. The solubility of the (MMPI) material was taken at different temperatures with a mixture of solvent Methanol: Acetonitrile (1:1). The grown MMPI crystal structure and cell parameters were solved via single crystal X-ray diffraction analysis. The structural formation of the title material was also confirmed by Nuclear Magnetic Resonance spectroscopic (NMR) studies. The experimental vibrational bands in the synthesized material have been assigned by Fourier Transform Infrared (FT-IR) spectrum analysis. From the optical analysis, the grown crystal’s lower cut-off wavelength, transmittance range, and optical band gap were calculated. Chemical etching analysis was carried out on the grown crystal surface (MMPI) to study the surface property of the grown MMPI crystal. Along with etching, atomic force microscope (AFM) and scanning electron microscope (SEM) were also used to analyses the grown MMPI crystal surface. Hirshfeld surface analysis was used to analyses the intermolecular interactions. HOMO and LUMO energies were calculated theoretically using the Gaussian View 6 programmer. The chemical activity was evaluated via the molecular electrostatic potential using the density functional theory (DFT) method. The third-order nonlinear optical parameters of the title crystal were evaluated at He-Ne laser (632.8 nm) source with the single beam Z-scan technique. In addition, it shows significant reverse saturable absorption and self-defocusing.

Theoretical and Experimental Investigation on 1,2,3‐Benzotriazole 4‐Hydroxybenzoic Acid (BTHBA) Single Crystals for Third‐Order Nonlinear Optical (NLO) Applications

Abstract1,2,3‐Benzotriazole 4‐hydroxybenzoic acid (BTHBA) is synthesized and single crystals of dimension 20 mm × 9 mm × 5 mm are grown from methanol solvent by conventional solution growth method. Single crystal X‐ray diffraction data show that BTHBA belongs to the orthorhombic crystallographic system with non‐centrosymmetric space group Pna21. The grown organic nonlinear optical (NLO) crystal is subjected to various characterizations like powder X‐ray diffraction, UV–vis–NIR, photoconductivity, thermogravimetric differential thermal analysis (TG‐DTA), and chemical etching analysis. Optimization of the molecular structure, highest occupied molecular orbital–lowest unoccupied molecular orbital energy, natural bond orbital analysis, molecular geometry, and molecular electrostatic potential are investigated using Gaussian 09w software. The laser damage threshold value of BTHBA crystal is estimated to be 13.4 GW cm−2 using a Nd:YAG laser. The third‐order NLO susceptibility of BTHBA crystal reveals relatively high values of about 8.95 × 10−9 esu when compared with that of standard potassium dihydrogen phosphate (KDP) (8.3 × 10−14 esu). Hence it can be effectively employed for various optoelectronic and photonic applications.

Study of the Crystalline Perfection, Homogeneity, Chemical Etching on the Surface, and Third‐Order Nonlinear Optical Properties of (1 1 0) Oriented Hydroxyethylammonium D‐Tartrate Monohydrate Single Crystal and Hirshfeld Surface Analysis

AbstractThe single crystal of hydroxyethylammonium D‐tartrate monohydrate (HEDT) is grown along the (1 1 0) plane using the Sankaranarayanan–Ramasamy method. The powder X‐ray diffraction and the high‐resolution X‐ray diffraction analyses are used to corroborate the growth plane and perfection of the crystallinity, respectively. The birefringence experiment has proven crystalline homogeneity and estimated birefringence value (Δn) is 0.109. The surface morphology of the grown crystal is examined by chemical etching analysis and irregular hillock patterns are found. The transmittance for the (1 1 0) plane of the HEDT is inspected by a UV‐Vis analysis. The second harmonic generation efficiency of the HEDT crystal is 1.7 times that of potassium dihydrogen phosphate (KDP). The third‐order nonlinear optical (TONLO) properties of the grown HEDT crystal are scrutinized by the Z‐scan experiment. The estimated TONLO susceptibility of HEDT crystal is 6.827 × 10−8 esu. The laser damage threshold value of HEDT is discovered to be 5.24 GW cm−2. The 3D Hirshfeld surface visualizes the interaction between HEDT molecules and analyzes the distance from the surface of the molecule to the farthest and the nearest atom. The important contributions of crystal packing are explored by 2D‐fingerprint plots.

Fluorescence emission, life time, thermal properties of trans-stilbene mixed diphenylacetylene scintillator crystal

Diphenylacetylene (DPAC) is a promising organic scintillator material for fast neutron detection. Solubility measurement was carried with two different solvents such as toluene and methanol. Stilbene mixed diphenylacetylene (DPACS) was successfully harvested from toluene with the dimensions of 42 × 12 × 8 mm3. X-ray diffraction confirms the monoclinic crystal structure with the obtained lattice parameters. The vibrational characteristic functional group was identified by FTIR studies. UV–Vis spectral analysis of the grown DPACS crystal reveals good optical transparency in visible and near IR region. The thermal behaviour and melting point of the sample was analysed by TGA-DSC. Chemical etching analysis was carried out on the crystal surface at an ambient temperature to see the dislocations and growth pattern of the crystal. Fluorescence broad emission peak was observed and the prompt and delayed fluorescence lifetimes of the DPACS were calculated.

Defect depth-profiling in kesterite absorber by means of chemical etching and surface analysis

Defect depth-profiling in kesterite absorber by means of chemical etching and surface analysis

An Investigation on Thermophysical and Dielectric Properties of Ammonium Dihydrogen Phosphate Single Crystal for Opto-electronic Device Applications

Ammonium dihydrogen phosphate (ADP) crystal utilizes several applications such as Q-switching, electro-optical, and second harmonic generation in nonlinear optics. In the present article, a good-quality single crystal of ADP was grown via Sankaranarayanan–Ramasamy (SR) method for the dimension of 120 mm in length and 12 mm in diameter. The grown ADP crystal is used for diverse characterizations like FTIR spectral study, Vickers microhardness, second harmonic generation, photoluminescence, and chemical etching analysis. The photoacoustic spectroscopy analysis was used to study the thermal diffusivity of the sample. Thermal transport properties of the crystal are required for all types of heat transfer incidences and furthermore used in several applications like acousto-optical, Nd:YAG, and Nd:YLF lasers. A dielectric property was investigated for the grown crystal with dissimilar temperatures, and it was apt for electro-optical and Q-switching applications.

Study of the influence of etching mixture components on the frosted glass effect

The wide use of glass results from its easy accessibility, plasticity and the possibility of modifications that change its strength and functional properties. In order to reduce the transparency of the glass, the material is subjected to a matting process. The aim of the research was to select the components of the matting mixture so that the glass surface was modified to give the "frosted glass" effect. Cluster analysis, Pareto diagrams of parameters significantly affecting the size of the pits formed during the chemical etching of glasses, profiles of approximated values and the usefulness of the chemical etching analysis of the glass surface were presented. The use of HCl and NH4F enables even matting of the glass surface. The addition of Na2CO3 did not significantly affect the matting process of the glass surface and the higher concentration of BaSO4 causes the formation of crystallites on the glass surface.

Tritium retention in displacement-damaged tungsten exposed to deuterium-tritium gas mixture at elevated temperatures

Abstract W samples, previously irradiated with 20 MeV W ions at room temperature to a displacement-damage level of 0.23 displacements per atom (dpa) at the peak of displacements, were exposed to a deuterium-tritium (D2 ― DT ― T2) gas mixture with a tritium content of 6% at a total pressure of 1.2 kPa and temperatures of 773 K and 973 K for 3 h. The concentration of tritium retained in the displacement-damage zone of these W samples was determined by a method combining chemical etching and subsequent analysis of tritium in the etching solution using liquid scintillation counting (CE-LSC). (Some figures may appear in colour only in the online journal)

Defect depth-profiling in kesterite absorber by means of chemical etching and surface analysis

A method to probe the depth morphology, defect profile and possible secondary phases in a thin film semiconductor is presented, taking a standard Kesterite film as an example. Using a top-down approach based on a previously reported controlled Methanol-Br2 chemical etching, well-defined slabs of a state of the art Kesterite absorber are fabricated. The analysis of their morphology both by Scanning Electron Microscopy and 3D optical Profilometry reveals the extent of a previously reported poor film morphology toward the back interface, and we are able to determine that more than 50% of a standard absorber is disconnected from the substrate. More importantly, these etched films are subsequently analyzed by surface sensitive techniques such as X-ray Photoelectron Spectroscopy and UV-Raman analysis. An accurate composition profile is established, and for the first time, a direct observation of the defects’ nature and their depth profiling in Kesterite is made possible. While VCu are found with a constant amount throughout the absorber, indicating a homogenous carrier concentration, a prevalence of the ZnSn defect is observed with a steep gradient toward the back interface, associated with an increase in the SnSe2 secondary phase. With bulk defects being often pointed out as the intrinsic limitation of this material, this result highlights what possibly is the main impediment of Kesterite solar cells, and a critical point to address in the design of future devices. Beyond the case of Kesterite absorbers, the method presented here offers a combination of simplicity, tunability and versatility making a straightforward transfer to other emerging thin film absorbers feasible, and it could possibly be an important tool in their future performance assessment and comparison.

Crystal growth, structural, optical, thermal, and mechanical properties of new bis(2-amino-6-methyl pyridinium barbiturate) tetrahydrate organic single crystal for nonlinear optical applications

In the present work, a new supramolecular synthon material of bis(2-amino-6-methyl pyridinium barbiturate) tetrahydrate (2A6MBA) has been grown as a single crystal by slow evaporation solution growth method at ambient temperature. The structure of the grown crystal was resolved by single crystal X-ray diffraction (SXRD). It was revealed that the grown 2A6MBA crystal crystallizes in a triclinic crystal system with the centrosymmetric space groupP1¯. The crystallanity of the synthesized 2A6MBA crystal was confirmed through powder X-ray diffraction studies (PXRD). 1H nuclear magnetic resonance (NMR) spectra of the crystal confirmed the various hydrogen exposes of the 2A6MBA structure and the series of functional groups were illustrated through Fourier transform infrared (FTIR) spectral analysis. Ultraviolet-visible (UV–vis) spectrometer exposed that the synthesized grown 2A6MBA crystal has a lower cut-off wavelength and a wide transmission window, which makes it suitable for optoelectronic applications. The photoluminescence (PL) spectrum illustrated the emission of light at 378 nm with an excitation wavelength of 349 nm. In thermo-gravimetric differential scanning calorimetric (TG-DSC) analysis, thermal stability, melting point, and weight loss of the grown 2A6MBA crystal were examined. The Vicker's microhardness test perceived the hardness related parameters of the grown 2A6MBA crystal to analyze its suitability for post growth device fabrications. The growth feature of 2A6MBA crystal was revealed through chemical etching analysis. Second harmonic generation (SHG) studies explore the nonlinear optical property of the grown 2A6MBA crystal.

Crystal growth, surface morphology, mechanical and thermal properties of UV-nonlinear optical crystal: Mercury cadmium chloride thiocyanate (MCCTC) single crystal

Single crystal of mercury cadmium chloride thiocyanate (MCCTC) was grown by slow evaporation solvent method at ambient temperature (SEST) with a dimension of 10×5×5 mm3. The grown single-crystal’s structure and lattice constant, density and volume were estimated by using single-crystal X-ray diffraction studies. Additionally, the chemical etching and atomic force microscopy (AFM) analysis were used to investigate reverse growth and surface morphology. Moreover, the mechanical properties such as, hardness number, yield strength, Mayer index number, and stiffness constant were calculated by Vickers’s micro-hardness measurement. The thermal stability of grown single is stable up to 171 °C observed from TG-DSC, which reveals that the sample posses low thermal stability compared to other organometallic thiocyanate families of single crystals like MMTC(381°C), MFCTC (241°C) and ACCTC (247 °C). The non-linear optical study of second harmonic generation efficiency for MCCTC single crystal is 17 times superior to Urea.

Polarity Control of ZnO Films Grown on Ferroelectric (0001) LiNbO3 Substrates without Buffer Layers by Pulsed-Laser Deposition.

For this study, polarity-controlled ZnO films were grown on lithium niobate (LiNbO3) substrates without buffer layers using the pulsed-laser deposition technique. The interfacial structure between the ZnO films and the LiNbO3 was inspected using high-resolution transmission electron microscopy (HR-TEM) measurements, and X-ray diffraction (XRD) measurements were performed to support these HR-TEM results. The polarity determination of the ZnO films was investigated using piezoresponse force microscopy (PFM) and a chemical-etching analysis. It was verified from the PFM and chemical-etching analyses that the ZnO film grown on the (+z) LiNbO3 was Zn-polar ZnO, while the O-polar ZnO occurred on the (-z) LiNbO3. Further, a possible mechanism of the interfacial atomic configuration between the ZnO on the (+z) LiNbO3 and that on the (-z) LiNbO3 was suggested. It appears that the electrostatic stability at the substrate surface determines the initial nucleation of the ZnO films, leading to the different polarities in the ZnO systems.

Verification of threading dislocations density estimation methods suitable for efficient structural characterization of AlxGa1−xN/GaN heterostructures grown by MOVPE

Selection of a suitable chemical etching method for threading dislocations density estimation is crucial for the structural characterization of epilayers grown by MOVPE and thus further for device fabrication. In this work, threading dislocations density in single layer and AlxGa1−xN/GaN periodical heterostructures has been investigated by means of chemical etching and XRD analysis. For chemical etching, two types of agents have been used: phosphoric acid (220°C/7.5min) and a molten mixture of KOH-NaOH (440°C/2.5min). Estimation of dislocation density has been carried out on the basis of SEM images. It was shown that defect-selective etching in molten alkaline solution is more effective than etching in phosphoric acid and provides more accurate data that are in agreement with data obtained from XRD characterization.

Synthesis, growth and physicochemical properties of new organic nonlinear optical crystal l-threoninium tartrate (LTT) for frequency conversion

An organic nonlinear optical l-threoninium tartrate (LTT) single crystal was successfully grown by slow evaporation method using de-ionized water as solvent. The orthorhombic structure and non-centrosymmetric space group of P2221 of the grown LTT crystal was confirmed using single crystal X-ray diffraction analysis. The various functional groups and bonding nature of the LTT crystal were realized using FT-IR spectroscopic analysis. The linear optical behavior is examined using UV–Visible spectroscopy revealing the absences of absorbance in the wavelength region of 230–1100 nm. Tauc’s relation is employed to obtain the optical band gap and it is found to be 6.4 eV. The optical parameters like extinction coefficient (K), reflectance (R) and refractive index (n0) are also calculated for the grown LTT crystal. With respect to the frequency and temperature the dielectric constant and dielectric loss were estimated. The Vickers hardness number (Hv), Meyer’s index (n), yield strength (σr), elastic constant (C11), fracture toughness (KC) and Brittle index number (Bi) were calculated using the micro-indentation test. Thermo-gravimetric (TG) and differential thermal (DT) analysis confirm the single stage decomposition and 257 °C melting point of the titular crystal. The exact melting point of the crystal is found to be 268 °C using auto melting point apparatus. The layer growth with 2D nucleation mechanism and less dislocation is confirmed by chemical etching analysis. The surface quality of the titular crystal was studied using laser damage threshold (LDT) measurement and it is found to be 6.57 GW/cm2. Kurtz and Perry method was employed to estimate the second harmonic generation efficiency of the titular crystal and is found to be 2.91 times greater than the KDP crystal. The χ(3), n2 and β of the titular crystal was estimated using Z-scan technique and they are found to be 7.1368 × 10−10 (esu), 0.8466 × 10−12 (cm2W−1) and 3.734 × 10−6 (cmW−1) respectively. Reverse saturable absorption observed in open aperture Z-scan indicates the suitability of titular crystal for optical limiting application.

Growth of high-quality organic single crystal of 2-aminopyridinium 4-nitrophenolate 4-nitrophenol (2AP4N) by a novel Rotational Sankaranarayanan–Ramasamy (RSR) method

The good quality 2-aminopyridinium 4-nitrophenolate 4-nitrophenol (2AP4N) single crystals have been grown by (i) Sankaranarayanan–Ramasamy (SR) method and (ii) Rotational Sankaranarayanan–Ramasamy (RSR) method. The effect of rotation on unidirectional crystal growth method (RSR) has been reported for the first time. The apparatus was specially designed and developed for the growth of high-quality crystals by slow cooling under rotational conditions. The high-quality crystals have been achieved under forced convection and the quality of the crystal is compared to the crystals grown under free convection conditions. The crystal structure was analyzed by single crystal X-ray diffraction (SXRD) measurement. The grown crystal was subjected to the powder X-ray diffraction (PXRD) analysis to confirm the growth direction along (0 0 1) plane. The optical quality of the grown crystals has been analyzed by UV–Vis NIR spectrophotometer. It confirms that the grown crystal is highly transparent in the visible and near IR region. The photoluminescence behaviour was recorded in the wavelength region between 450 and 700 nm. It confirms that the grown crystal has emission at 500 nm. The electro-optical properties of the grown crystal were analyzed by photoconductivity measurement and it has positive photoconductivity nature. The grown crystal has less dislocation densities as confirmed by chemical etching analysis. The mechanical strength was investigated by Vickers microhardness tester. The frequency dependent dielectric properties of the crystals were investigated. The laser damage threshold (LDT) was measured for both SR and RSR method grown crystals. The full-width at half maximum (FWHM) of high-resolution X-ray diffraction (HRXRD) curves indicate that the grown crystal has high crystalline perfection. The results obtained from the SR and RSR method grown 2AP4N crystals were compared. The RSR method grown crystal has higher optical transparency, higher photoluminescence, higher photoconductivity, higher mechanical strength, higher laser damage threshold, higher crystalline perfection, less dislocation density, low dielectric loss and low full with at half maximum (FWHM). The second harmonic generation (SHG) of 2AP4N was analyzed by Kurtz-Perry powder technique. The SHG efficiency was found to be 4.5 times that of reference KDP material. The above studies reveal that the RSR method grown crystals are more useful for device applications.