Triglycine Sulfate Research Articles

A pyroelectric thin film of oriented triglycine sulfate nano-crystals for thermal energy harvesting

This study introduces a method for the fabrication of transparent and flexible pyroelectric thin films containing oriented triglycine sulfate (TGS) nanorods for thermal energy conversion or thermal sensing. For the fabrication of such thin films a highly nanoporous anodic aluminum oxide (AAO) template is mounted on top of a b-cut TGS seed crystal before filling the template’s nanopores with TGS solution. Crystal growth in the filled pores is done via the so-called temperature-lowering technique. Two principles are applied to grow oriented nanocrystals in the AAO template: first, the effect of different crystal growth rates in different directions of a nanopore’s confined space is exploited. Second, crystal growth at the bottom of the pores is initiated in a preferential direction by the TGS seed crystal. As confirmed by x-ray diffraction the crystal nanorods obtained are oriented in the desired spontaneous polarization vector of TGS (b-direction). Optical transparency of the filled AAO thin film is good when compared to a pure AAO film which indicates a reasonably high homogeneity and a reasonably low defect density of the TGS nanocrystals. Dielectric characterization at 1 kHz shows a relative permittivity similar to a bulk TGS crystal and a high resistivity of about 199 MΩ m. At its phase transition temperature (44 °C), the dielectric loss factor of the thin film is about 0.3. An average pyroelectric coefficient of 133 μC m−2 K−1 and a relative permittivity of 15.6 are calculated from measurement results at room temperature, taking the effect of the AAO thin film into account. With that, the pyroelectric voltage figure of merit (FOM) (pc/εrε0) and the energy harvesting FOM (pc2/εrε0) and are about 820 kV m−1 K−1 and 72 J m−3 K−2, respectively. In comparison to other approaches for growing thin films of oriented TGS crystals, the described method exhibits advantages concerning the growth of oriented nanocrystals, simplicity, fast growth, and an access to both sides of the nanocrystals.

Influence of Gamma Irradiation on Properties of Ferroelectric Composite from Cellulose Nanoparticles and Triglycine Sulfate

Influence of Gamma Irradiation on Properties of Ferroelectric Composite from Cellulose Nanoparticles and Triglycine Sulfate

Effect of the Degree of Overcooling on Relaxation of the Domain Structure of Triglycine Sulphate

The formation and evolution of the domain structure in the vicinity of the Curie point is studied in triglycine sulfate crystals subjected to fast cooling TC. We derive an analytical expression for time dependence of the mean characteristic domain size. This expression enable us to investigate the process of enlargement of domain structure through all stages of its relaxation into a state of thermodynamic equilibrium. The model predicts a root-square behavior of the mean domain size, which agrees well with available experimental data. The rate of enlargement of the domain structure is shown to depend on the degree of overcooling. The time dependence of the mean domain size obtained in this study enables us to determine the radius of intermolecular interactions in the crystals under study.

Dielectric properties of composite materials based on P(VDF-TrFE) copolymer and deuterated triglicyne sulfate crystal

The film structures on the base of soft and crystalline ferroelectrics (poly(vinylidene fluoride - trifluoroethylene) copolymer and deuterated triglycine sulfate) were produced. The volume content of the DTGS microcrystal particles embedded in the polymer matrix of the composite films was up to 10%. It was found crystalline phase changes in the polymer matrix at the DTGS inclusions presence. The DTGS crystal particles increased dielectric permittivity and electrical conductivity of the composite films. The temperature dependences of the dielectric permittivity indicated increasing the phase transition temperature of polymer matrix at the DTGS inclusions growth.

Fractional-Differential Model of Heat Conductivity Process in Ferroelectrics under the Intensive Heating Conditions

Ferroelectrics, due a number of characteristics, behave as hereditary materials with fractal structure. To model mathematically the systems with so-called memory effects one can use the fractional time-derivatives. The pyro-electric properties of ferroelectrics arouse interest in developing the fractional-differential approach to simulating heat conductivity process.The present study deals with development and numerical implementation of fractal heat conductivity model for hereditary materials using the concepts of fractional-differential calculus applied to the simulation of intensive heating processes in ferroelectrics.The paper proposes a mathematical model governed through mixed initial-boundary value problem for partial differential equation containing a fractional time-derivative as well as nonlinear temperature dependence on the heat capacity. To solve the problem the computational algorithm was designed which is based on an analog of the Crank – Nicolson finite difference scheme combining with the Grunwald – Letnikov formula for fractional time-derivative approximation. The approximation of Neumann boundary condition is included into the finite difference problem statement using scheme of fictitious mesh points. The total system of linear algebraic equations is solved by sweep method.The designed application program allows one to perform the computer simulation of heat conductivity process in hereditary materials. The model verification was performed for numerical solving test problem with known analytical solution. The results of computational experiments are demonstrated for the example of estimating heat distribution in a typical ferroelectric crystal of TGS (triglycine sulfate) near the temperature of phase transition. The fractional derivative order was approximately evaluated to be ~0.7 at variation of this parameter. We applied the comparison of fractal model implementation results with experimental data related to the time when the ferroelectric crystal is heated to Curie temperature. These findings demonstrate that one needs to use the modified models at the analysis of the field effects arising in hereditary materials.

Shock wave-induced defect engineering for investigation on optical properties of triglycine sulfate crystal

A systematic investigation of shock wave-induced defect engineering on optical transport properties of triglycine sulfate (TGS) crystalline material is carried out under shock waves of Mach number 1.7 with a different number of shock pulses. Surface morphological changes and defect concentration are evaluated by the optical microscopic technique. Optical transmission of pre- and postshock wave-treated TGS crystal is analyzed using UV–visible spectrometer over the range between 200 and 800 nm. Unexpectedly, during the shock wave impact conditions, the test crystal exhibits vulnerability due to defects on its surface and it is confirmed by optical micrographs. Optical transmission is continually reduced while the number of shock pulses is increased due to the formation of defects on the surface of the test sample. Followed by the observation of optical transmission, optical constants and band gap energies are also calculated. The obtained results clearly show that surface morphology and optical transport properties of TGS crystal are greatly affected by the impact of shock waves.

Bulk-fill versus conventional composite: A comparative analysis on degree of conversion

Abstract Aim: This study aimed to determine the degree of conversion (DC) of two resin-based composites: a conventional nanohybrid composite and a bulk-fill flowable composite (SureFil® SDR™ flow). Materials and Methods: DC was evaluated at 1-, 2-, 3-, and 4-mm depths at varying irradiation times (20 and 40 s) by Fourier-transform infrared spectroscopy. Disc-shaped specimens of varying depths were prepared and photoactivated with a third-generation light-emitting diode light-curing unit. The specimens were stored for 24 h in the dark at ambient temperature and pulverized into a fine powder which was mixed with potassium bromide. After homogenization, the mixture pressed to form a pellet. All pellets were evaluated by an infrared spectrometer equipped with a triglycine sulfate detector using diffuse reflectance. The percentage of monomer conversion was determined from the ratio of the absorbance intensities of the aliphatic carbon–carbon double bonds (C = C) and the internal standard before and after the curing of the composite, represented by the aromatic carbon–carbon single bonds (C-C). Results: The DC data for the bulk-fill resin showed no significant difference (P > 0.05) for different irradiation depths, whereas for the conventional nanohybrid resins, statistical analyses revealed a significant result of the variables time and depth as well as the interaction between them. Conclusions: The results indicated that SDR™ achieves a 4-mm depth of cure with both 20- and 40-s light exposures.

Preparation and dielectric properties of a mixed ferroelectric composite from nanoparticles of cellulose and triglycine sulfate

In this study, a novel ferroelectric composite consisting of triglycine sulfate (TGS) and cellulose nanoparticles (NCCP) prepared from waste cotton was synthesized and characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Zetasizer analyzer. The study on electrophysical properties of the composite were performed from 25 to 120 ˚C under a weak electric field with an amplitude of 1 V/cm at low and infra-low frequencies (10−3 to 103 Hz) with different weight composition ratios. The obtained results indicated that the increase in cellulose concentration in the composite led to increasing the phase transition temperature in TGS component by 3 to 63 °C higher than those for single crystal TGS (+49 °C). The corresponding increase of the Curie temperature in composites was presumably connected with the strong interaction between TGS and cellulose nanoparticles through the system of hydrogen bonds. In the temperature range 100–115 °C, where the structural changes in pure triglycine sulfate were recorded earlier in the case of high-temperature annealing, a characteristic growth of the dielectric permittivity was also observed. The study on low and infra-low dispersion of dielectric permittivity was carried out and explained by Maxwell-Wagner-Sillars interfacial mechanism.

Effects of composition ratio on structure and phase transition of ferroelectric nanocomposites from silicon dioxide nanoparticles and triglycine sulfate

ABSTRACTThe present work is devoted to study on influences of silicon dioxide nanoparticles (SiO2) on structure and phase transition of a classical ferroelectric of triglycine sulfate (TGS) by synthesizing a composite containing SiO2 and TGS at different composition weight ratios. Particle size analysis, X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) techniques were utilized to charaterize the synthesized composite. The experiments for investigation of phase transition were conducted from 20 to 120°C under a weak electric field (1 V.cm−1) at 1 kHz. The results revealed an expansion of ferroelectric phase of TGS by 15–55°C with increasing the SiO2 content. Besides, an additional phase transition point which is characteristic for the bulk clusters of TGS was found at low content of SiO2. The detected anomalies were discussed thoroughly based on the interaction between components in the composite.

Effects of Moisture on Structure and Electrophysical Properties of a Ferroelectric Composite from Nanoparticles of Cellulose and Triglycine Sulfate

In this study, a novel ferroelectric composite consisting of triglycine sulfate and cellulose nanoparticles at different weight composition ratios was successfully synthesized. A comparative study on structure and electrophysical properties for dried and wet composite samples was carried out. The measurements of electrophysical parameters were performed from 10 to 120 °C under a weak electric field with an amplitude of 1 V cm−1 at low and infra-low frequencies (10−3–103 Hz) under different relative humidities of 0, 30, 60, 80, and 100%. The characterization results showed a significant impact of moisture on crystallinity and features of functional groups in the composite. Besides, phase transition temperature of the composite increased by 3 to 63 °C higher than those for single crystal of triglycine sulfate (+ 49 °C) in dependence on cellulose content in the composite. Along with a significant increase in dielectric constant, dielectric loss, and dielectric dispersion in the composite due to high conductivity caused by moisture, the water molecules on sample surface led to the appearance of addition peaks in temperature dependences of dielectric constant and dielectric loss tangent in the initial stage of heating. All the anomalies can be explained by the strong interaction through hydrogen bonds between triglycine sulfate and cellulose components as well as between these components and water molecules in the composite.

The Impact of Weak Magnetic Fields on Ferroelectric Crystals with Hydrogen Bonds

The paper presents the review of works devoted to the effects of weak (with induction not exceeding 0.3 T) pulsed and a constant magnetic fields on the dielectric characteristics of hydrogen-containing ferroelectric crystals. By using the example of nominally pure triglycine sulfate and potassium dihydrophosphate, such weak magnetic fields were shown to cause a significant increase in the dielectric constant, coercive field, and a noticeable shift in the temperature of the ferroelectric phase transition. The interest shown in such studies is that the effects considered cannot be explained from the point of view of classical thermodynamics. For a long time, there was an opinion that magnetic fields with induction of less than 1 T in principle cannot affect the physical properties of diamagnetic materials in any way. However, experiments with numerous diamagnetic treated with weak magnetic fields showed the fallacy of such an opinion. The ferroelectric crystals referred to in the proposed work are also diamagnetic. Therefore, the apparatus of classical thermodynamics is not suitable for explaining the effect on the processing properties of weak magnetic fields. The effects of exposure are explained by the participation of protons of hydrogen bonds, which stabilize defective complexes, in electronic transitions responsible for the decay of these complexes and/or detachment of domain walls from them. An indirect confirmation of this explanation is the absence of the effect of magnetic fields (at least in the induction range 0.02-0.30 T) on single-crystal samples of barium titanate BaTiO3, an octahedral-type ferroelectric that has no hydrogen bonds in its structure.

Enhanced structural, optical, thermal, mechanical and electrical properties by a noval approach (nanoparticle doping) on ferroelectric triglycine sulphate single crystal

The pristine and AgNP-doped TGS crystals are studied using powder X-ray diffraction, density measurements, solubility studies, UV–Vis analysis, photoluminescence spectroscopic analysis, thermal gravimetric analysis, differential thermal analysis, differential scanning calorimetry, Vicker’s hardness measurements, I–V and impedance measurements. From the XRD studies, TGS crystal formation is confirmed and by further analyzing X-ray diffraction data it is noticed that the incorporation of nanoparticles induce stress in the lattice of TGS crystal, which, in turn, lead to shift in peak positions. Crystal solubility and density values are increased after doping process. From the emission spectrum it is evident that emission intensity increases as the doping concentration increased. The melting point and mechanical hardness of the crystals also showed improvement after AgNP doping. Band gap calculated by Tauc’s relation is found to decrease with increase in doping concentration. Further, electrical studies demonstrated that crystal conductivity is improved as the doping concentration increases.

Focus on analytical equipment, sensors, and instrumentation

Focus on analytical equipment, sensors, and instrumentation

Влияние глубины переохлаждения на релаксацию доменной структуры триглицинсульфата

The process of formation and evolution of the domain structure in triglycine sulfate (TGS) crystals after rapid cooling in the vicinity of the Curie point of the ТС has been considered. An analytical expression for the time dependence of the characteristic average size of the domain, which allows us to trace the process of enlargement of the domain structure at all stages of its relaxation to the state of thermodynamic equilibrium has been obtained. It was shown that the average size of a domain grows according to the square root law, which is in good agreement with known experimental data. It was established that the growth rate of the domain structure depends on the undercooling depth of the sample. The dependence of the characteristic average size of the domain on time obtained in this work allows us to determine the radius of the intermolecular interaction of the crystals under study.

Learning the Second-order Phase Transition Through Experiments:Targeting the Ferroelectric Phase Transition of Triglycine Sulfate (TGS)

Learning the Second-order Phase Transition Through Experiments:Targeting the Ferroelectric Phase Transition of Triglycine Sulfate (TGS)

Применение сканирующей емкостной силовой микроскопии для выявления примесных фаз в сегнетоэлектрике триглицинсульфат

The results of the study of inhomogeneous ferroelectric triglycine sulfate single crystal with a growth periodic impurity structure TGS - TGS + Cr are presented. The impurity distribution was investigated with scanning capacitance force microscopy (SCFM). The peculiarities of the capacitance variations imaging on a doubled and tripled resonant frequency of electrostatic force are considered. The piezoelectric response, surface potential and surface topography were studied. It is shown that capacitive contrast is formed both at the domain boundaries and in the TGS and TGS + Cr bands. It was shown that SCFM allowed one to observe the impurity spatial distribution in the ferroelectric structure at the difference in the chromium concentration about 0.02-0.08 wt%.

Self-Organized Ferroelectric Domains Controlled by a Constant Bias from the Atomic Force Microscopy Tip.

The ferroelectric polarization switching along an external electric field is most important for the applications of ferroelectric memories and piezoelectric sensors and actuators; however, the depolarization commonly occurs randomly and cannot be controlled exactly until now. Here, a tip bias introduces the polarization switching and a ∼10 μm-scale domain in a triglycine sulfate crystal, and then the polarization backswitching as a special depolarization introduces a series of ordered granular domains along a line being parallel to the c axis and through the tip which divides the original domain to two similar parts. Such backswitching is controlled by the surface charge change as a result of the interplay among polarization charges, mobile H+ ions at the surface, and the strong crystal anisotropy. The self-organized ferroelectric domains offer us a new freedom to design novel ferroelectric or piezoelectric devices in future.

Big bore and extremely flexible mid-infrared hollow waveguide for gas absorption module

Big-bore, low-loss, and extremely flexible hollow waveguides were fabricated for mid-infrared spectroscopic gas sensing. The waveguide with inner/outer diameter of 1.4/2.0 mm can be curved with a bending radius as small as 1.4 cm A module of gas absorption cell for spectroscopic sensing was proposed with the hollow waveguide curved into a channeled substrate. Hollow waveguide with inner coatings of silver and silver iodide films attains low loss in the mid-infrared region for methane gas detection. Sensing properties for the module was experimentally discussed. Limit of detection of 6 ppm was obtained by using an FTIR (Fourier Transform infrared spectroscopy) system and DTGS (deuterated triglycine sulfate) detector. Comparisons were made to metallic hollow waveguide only with silver inner coating.

The photothermoelectric effect of liquid thermoelectrics as a tool for the detection of ferro–paraelectric phase transitions in solids

A new application of the liquid thermoelectrics (LTE) is proposed: the detection of phase transitions in ferroelectric solids. Concretely, the Seebeck effect generated in a known LTE material (dodecanol + 10−1 mol L−1 tetrabutylammonium nitrate) was used as a tool for the detection of the antiferro–paraelectric phase transition of triglycine sulphate (TGS). TGS was selected as a sample because it is a ferroelectric solid with a convenient Curie point close to room temperature (about 49 °C). The advantages of the present method (compared with previously reported investigations performed with solid thermoelectric materials as sensors) are two: (1) no coupling fluid between the sensor and sample is necessary (the liquid sensor–solid sample thermal contact is perfect); (2) the liquid sensor allows for investigations of samples with irregular geometry. Based on the recently developed theory of the photothermoelectric method, the behaviour of the static volume specific heat and dynamic thermal diffusivity, conductivity and effusivity of TGS around the Curie point has been obtained.

In Situ Observation of the Phase Transition of a Ferroelectric Triglycine Sulfate Crystal by Piezoresponse Force Microscopy

The second-order phase transition in a ferroelectric triglycine sulfate crystal is studied in situ by piezoresponse force microscopy. For the first time, the formation of a metastable one-dimensional quasiperiodic polarized structure is observed in the critical region of the phase transition, within one degree near the Curie temperature. Via image processing, the temperature dependence of the parameters of the quasiperiodic structure is studied. At a temperature exceeding the phase-transition point by one degree or more, the usual domain structure is formed, the width of the domains and the spread of the widths with respect to their mean value increase significantly.