Harsh Yadav

Structural, electrical, ferroelectric and mechanical properties with Hirshfeld surface analysis of novel NLO semiorganic sodium p-nitrophenolate dihydrate piezoelectric single crystal

Novel non-linear sodium para-nitrophenolate dihydrate (SPNPD) single crystals were grown by the controlled evaporation method. Various functional groups and chemical bonding were identified by FTIR and Raman analysis. Hirshfeld surface and fingerprint plots were drawn and analyzed to investigate the intermolecular interactions present in the crystal structure. UV-visible studies indicate the high transmittance of the crystals in the visible region with a wide band gap 2.80 eV. In the photoluminescence spectrum, a sharp broad emission peak centered at 525 nm indicates green emission. In the dielectric study a broad peak with low dielectric constant value was observed at 34 °C which may be due to a ferroelectric to paraelectric transition. Piezoelectricity was confirmed by determining the piezoelectric charge coefficient (d33 = 2.24 pC N−1). The hysteresis loop shows values of remnant polarization and coercive field of 2.67 μC cm−2 and 7.43 kV cm−1, respectively. Piezo-/ferroelectricity were reported for the first time in p-nitrophenolate based compounds. SHG efficiency of this material was found to be 4.15 times of that of KDP. The mechanical strength was confirmed from a Vicker’s microhardness study and void volume. Thus the promising piezoelectric, ferroelectric behavior of the material along with high SHG efficiency and low dielectric constant, established SPNPD as a potential material for transducer, optoelectronics and nonvolatile memory devices applications.

Growth and characterization of piezoelectric benzil single crystals and its application in microstrip patch antenna

Organic non-linear optical single crystals of benzil have been grown by Czochralski (Cz) and slow-evaporation techniques. The crystal morphology was characterized by computing the growth rates of the planes, which were found to be affected by solvent modification. Intermolecular interactions of the benzil crystal were explored by Hirshfeld surface and 2D fingerplot in a novel visual manner. A linear optical study was carried out by UV-vis transmission spectroscopy, in which the Cz grown crystal was found to be more transparent with a cut-off wavelength at 406 nm. Photoluminescence emission was observed in the green region with higher intensity in Cz grown crystal. The piezoelectric charge coefficients were found to be 4, 1, 6 and 3 pC N−1 along (100), (010), (001) and (10) planes of the solution grown crystal. The study of Vickers microhardness and volume of voids in the grown crystals confirmed that the Cz grown crystal has better mechanical strength. Patch antenna based on the substrate of Cz grown benzil crystal was simulated for resonant frequency at 12.6 GHz and fabricated, and is suitable for piezoelectric, sensor and telecommunication applications.

Performance of crystal violet doped triglycine sulfate single crystals for optical and communication applications

Single crystals of 0.01 and 0.02 mol% crystal violet dye doped triglycine sulfate (NH2CH2COOH)3·H2SO4 (TGS) have been grown by a slow evaporation technique. Enhanced dielectric, optical, thermal and mechanical properties have been achieved by dye doping. Monoclinic structures showing particular coloring patterns and morphology change with dye concentration were obtained. Various functional groups and dye incorporation in the grown crystals were confirmed qualitatively by FTIR and Raman analysis. A significant increase in Curie temperature from 50 to 55 °C with a decrease in maximum permittivity has been observed. The UV-vis spectra showed an increased transmittance window and an increased optical band gap from 5.61 to 6.11 eV as a result of doping. An increase in the sharpness and intensity of the photoluminescence peak with a blue shift has been observed in doped crystals. The thermal stability and the decomposition temperature were found to increase by about 10 °C in 0.01 mol% dye doped TGS. The mechanical strength of the grown crystals was estimated by the Vickers microhardness test and was found to be high for dye doped TGS. A high piezoelectric charge coefficient d33 of 16 pC N−1 was observed for pure TGS which decreased as a result of the dye effect. The fabrication of a patch antenna was carried out after simulating its resonant frequency, making it suitable for telecommunication applications.

Synthesis of 0.64Pb(Mg1/3Nb2/3)O3–0.36PbTiO3 ceramic near morphotropic phase boundary for high performance piezoelectric, ferroelectric and pyroelectric applications

Abstract A near MPB composition of 0.64PMN–0.36PT ceramic has been synthesized by solid-state reaction technique using columbite precursor. Sintering at 1030 °C resulted in a single perovskite phase with tetragonal structure having uniform and dense microstructure as revealed by powder XRD, Raman spectroscopy and FESEM analyses. An excellent dielectric response was obtained with room temperature dielectric permittivity value of 142 and high-phase transition temperature (Tm) of 210 °C at 1 kHz. A huge value of piezoelectric charge coefficient (490 pC/N) was obtained, which shows potential of PMN–PT for piezoelectric device applications. Well-shaped and fatigue-free P–E hysteresis loops over a wide temperature range of 30–230 °C were traced. A very large value of pyroelectric coefficient (p ∼ 2739.2 μC m−2 °C−1) was obtained.

Growth, crystal structure, Hirshfeld surface, optical, piezoelectric, dielectric and mechanical properties of bis­(l-asparaginium hydrogensquarate) single crystal

Molecular organic single crystals of bis(L-asparaginium hydrogensquarate) monohydrate [BASQ; (C8H10N2O7)2·H2O] have been grown by solution technique. Crystallographic information was investigated by single-crystal X-ray diffraction (SCXRD) analysis. Hirshfeld surface and fingerprint plot studies were performed to understand the intermolecular interactions of the BASQ crystal in graphical representation. Functional group identification was studied with FT-IR (Fourier transform-IR) spectroscopy. The positions of proton and carbon atoms in the BASQ compound were analyzed using NMR spectroscopy. High transparency and a wide band gap of 3.49 eV were observed in the linear optical study by UV-vis-NIR spectroscopy. Intense and broad photoluminescence emissions at room temperature were observed in blue and blue-green regions. The frontier molecular orbitals of the BASQ molecule were obtained by the DFT/B3LYP method employing 6-311G** as the basis set. The dielectric study was carried out with temperature at various frequency ranges. The piezoelectric charge coefficient (d33) value of BASQ crystal was found to be 2 pC/N, which leads to its application in energy harvesting, mechanical sensors and actuators applications. In the non-linear optical study, the BASQ crystal showed promising SHG conversion efficiency. Mechanical properties of the BASQ crystal were studied experimentally by Vickers microhardness technique, which revealed that the grown crystal belonged to the softer category. BASQ crystal void estimation reveals the mechanical strength and porosity of the material.

Growth, crystal structure, Hirshfeld surface, dielectric and mechanical properties of a new organic single crystal: ‘Bis glycine’ squarate

A novel transparent organic crystal ‘Bis glycine’ squarate has been grown by a slow evaporation method. Single crystal XRD confirms the monoclinic lattice with space group C2/c in BGSQ crystal with a refinement value (R) of 0.06. The molecular electron charge density distribution of the BGSQ compound is described. The growth rate of the BGSQ crystal is estimated by morphological study. The Hirshfeld surface gives information about intermolecular interactions within the crystal structure and the fingerprint plot shows the nature and type of intermolecular close contact experienced by the molecules in a crystal. The FTIR spectrum confirms the various functional groups present in the grown crystal. Thermal stability and melting point (182.20 °C) were studied with TGA-DTA. The low value of the dielectric constant of BGSQ suggests that the crystal can be used in the microelectronics industry. In UV spectra, a lower cutoff value at 280 nm and a wide band gap of 4.25 eV for the BGSQ crystal are observed. Meyers index number (1.817) in hardness studies confirmed the soft nature of the crystals. Voids have been used to describe the mechanical strength of crystalline materials.

Growth, morphology, structure and characterization of L-histidinium dihydrogen arsenate orthoarsenic acid single crystal.

L-Histidinium dihydrogen arsenate orthoarsenic acid (LHAS) crystals were grown by the slow evaporation method. Single-crystal X-ray diffraction confirms monoclinic structure. The growth rates of various planes of LHAS crystals were estimated by morphological study. Hirshfeld surface and fingerprint plots were analyzed to investigate the intermolecular interactions at 0.002 a.u. present in the crystal structure. The functional groups and phase behavior of the compound are studied by FTIR spectroscopy and differential scanning calorimetry (DSC). A ferroelectric to paraelectric phase transition at 307 K was observed in dielectric studies. The piezoelectric charge coefficients of the grown crystal were found to be 2 pC/N. The values of coercive field (Ec), remnant polarization (Pr) and spontaneous polarization (Ps) in the hysteresis loop are found to be 5.236 kV cm(-1), 0.654 µC cm(-2) and 2.841 µC cm(-2), respectively. Piezoelectricity and ferroelectricity are reported for the first time in LHAS crystals. The mechanical strength was confirmed from microhardness study and void volume. Due to the low value of the dielectric constant, and good piezoelectric and ferroelectric properties, LHAS crystals can be used in microelectronics, sensors and advanced electronic devices.