Journal of Materials Science: Materials in Electronics最新文献

Pure and glycine-doped ammonium dihydrogen phosphate (ADP) crystals have been grown using the slow solvent evaporation technique at room temperature. An investigation has been conducted to examine the effect of glycine doping on structural, vibrational, and optical properties and conductivity mechanism of pure ADP crystals. The analysis of powder XRD profile has suggested tetragonal structure symmetry with improved crystallite size and reduced lattice strain by glycine doping. The Raman spectrum study has indicated the presence of the characteristic vibrations of PO₄^3- and NH₄⁺ groups at around 925 cm^-1 and 1660 cm^-1, respectively. The influence of glycine doping on the linear properties of the pure ADP crystal has been determined based on the optical transmittance spectra. The direct optical bandgap increases by glycine doping; it is found to be 6.18 for pure ADP crystal and increases up to 6.25 for glycine-doped ADP crystals. The linear refractive index, optical density, extinction coefficient, optical conductivity, electric susceptibility, optical dielectric constant and loss, inter-band transition strength, volume, and surface energy loss factor have been found to be influenced by glycine doping. The optical study is further extended using the Wemple–DiDomenico single-oscillator model. The frequency-dependent ionic conductivity has been studied and obeys Jonscher’s power law. The modulus study shows that the conductivity relaxation is of non-Debye type. The exponent parameter for the pure ADP crystal is 0.620 and increases up to 0.691 for glycine-doped ADP crystals.

High power density electrostatic capacitor is a fundamental component of advanced electrical and electronic systems. Herein, the (Zn_1/3Nb_2/3)⁴⁺ complex ion was introduced into the B-site of Bi_0.385Na_0.325Ba_0.105Sr_0.155TiO₃ relaxor ferroelectric ceramics to improve energy storage properties and dielectric temperature stability. All pseudo-cubic structured ceramics have clear grain boundaries with an average grain size of 1 ~ 2 μm. In the optimized composition, a recoverable energy density of 2.4 J/cm³ with an energy efficiency of 78% can be achieved under a relatively low electric field of 160 kV/cm, together with excellent stability and reliability of energy storage in temperature, frequency, and cycling fields, as well as fast charging–discharging rate. This work provides guidance for the design of high-performance energy storage dielectric materials by enhancing the B-site disorder of relaxor ferroelectric ceramics via complex ion doping.

In the present work, polyaniline-reduced graphene oxide (PANI-rGO) nanocomposite films were synthesized by varying their concentration in composites of rGO nanosheets, and ammonium sulfate (NH₄)₂SO₄ was used as a catalyst. The microstructural, structural network, optical, compositional, and electrochemical properties of rGO/PANI nanocomposites were investigated using scanning electron microscopy X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). The XRD peaks obtained for both PANI and G/PANI Nanocomposite at 14.5^◦, 19.87^◦, and 25.6^◦, with the corresponding planes of (011), (020), and (200), confirm the successful synthesis of both PANI and G/PANI nanocomposites, resulting in a more ordered structure with high crystallinity during polymerization. FTIR, UV–Vis, and Raman spectroscopy results show that strong π − π interactions aided in the uniform distribution of PANI on the rGO nanosheets. Furthermore, the XPS results demonstrate the presence of C-H, N–H, C–C, and C-O bonds, corroborating the FTIR and Raman spectroscopy findings. The electrochemical properties of the PANI-rGO confirm its possible applications as a promising electrode material for high-performance supercapacitors.

The paper explores strategies to enhance the energy storage efficiency (η) of relaxor- ferroelectric (RFE) ceramics by tailoring the structural parameter tolerance factor (t), which indicates the stability of a perovskite. KTaO₃ (KT) with a t of 1.054 has been selected to modulate the t value of 0.75Bi_0.5Na_0.5TiO₃-0.25BaTiO₃ (BNT-BT, t = 0.9967), and a serials of (1 − x)(BNT-BT)-xKT (x = 0–0.10) RFE ceramics with t from 0.997 to 1.003 have been prepared. Structural analyses show that all the ceramics possess typical perovskite structure, and the average grain size decrease with the addition of KT. The tested dielectric characteristics present that with the increase of t to 1, the diffuse-phase-transition peak is gradually diminished in the dielectric constant vs temperature (ε_r-T) curves, while the relaxation-dielectric behavior is gradually strengthened, and the temperature stability of the dielectric constant is improved. The breakdown strength is also enlarged with the increase of KT content. As a result, the 0.94(BNT-BT)-0.06KT with t = 1.0004, which is closest to 1, achieving a recoverable energy storage density (W_rec) of 4.9 J/cm³ and η of 91.8% at 336 kV/cm, which are 191.7% and 49.5% higher than the W_rec (1.68 J/cm³) and η (61.4%) of pure 0.75BNT-0.25BT ceramic, respectively. These findings offer a promising approach for enhance the energy storage properties of RFE ceramics.

A simple synthesis method has been developed to improve the structural stability and storage capacity of MXenes (Ti₃C₂T_x)-based electrode materials for hybrid energy storage devices. This method involves the creation of Ti₃C₂T_x/bimetal-organic framework (NiCo-MOF) nanoarchitecture as anodes, which exhibit outstanding performance in hybrid devices. The 2D Ti₃C₂T_x nanorods are combined with NiCo-MOF nanoflakes through hydrogen bonding to create 3D Ti₃C₂T_x/NiCo-MOF composite. The electrochemical characteristics of Ti₃C₂T_x@NiCo-MOFs nanocomposite were measured. Due to enhancements in charge transfer and redox properties, the composite electrode consisting of Ti₃C₂T_x/NiCo-MOFs demonstrated a specific capacity of 1635.1 Cg⁻¹, significantly surpassing that of pure NiCo-MOFs (844.5 Cg⁻¹). Additionally, the hybrid supercapacitor device (Ti₃C₂T_x/NiCo-MOFs//AC) showed a specific capacity (Qs) of 222.53 Cg⁻¹ with an energy density (E_d) of 56 Wh/kg and a power density (P_d) of 2800 W/kg by using KOH as an electrolyte. The device achieved an impressive capacity recovery rate of 86.7% after being tested with up to 5000 charging and discharging cycles. This study opens new ways to make safe and reliable supercapacitors using environmentally friendly materials. The findings underscore the significant potential of Ti₃C₂T_x/NiCo-MOF in advancing the field of high-performance hybrid energy storage devices.

The photocatalytic performance of g-C₃N₄ could be effectively improved by reducing the recombination rate of photogenerated electron–hole pairs. In this work, g-C₃N₄ was combined with CoWO₄ to construct Z-scheme heterojunction by ultrasonic impregnation method. The successful synthesis of CoWO₄/g-C₃N₄ composites was confirmed by comprehensive characterization. Systematic studies showed that the well-matched band structures between them contributed to the formation of close interfacial contacts, which could effectively increase the transfer rate of photogenerated electrons. The photocatalytic degradation performance showed that the degradation efficiency of tetracycline (TC) reached 98.3% in 150 min under ultraviolet light, which was mainly due to the establishment of Z-scheme heterojunction. At the same time, CoWO₄/g-C₃N₄ composites could still maintain good stability after four cycles. In addition, the possible photocatalytic mechanism of CoWO₄/g-C₃N₄ composites was also proposed. This work provided an effective way for the preparation of efficient photocatalyst with the Z-scheme heterojunction.

In this study, optical and dielectric parameters of cholesteric liquid crystals were investigated. 4-pentyl-4′-cyanobiphenyl nematic liquid crystal and 4′-[(S)-2-methylbutyl]biphenyl-4-carbonitrile right-handed chiral dopant materials were used in the preparation of cholesteric liquid crystals. Furthermore, so as to determine the influence of chiral dopant, three samples were formed by combining 4-pentyl-4′-cyanobiphenyl and 4wt.%, 8wt.%, and 16wt.% 4′-[(S)-2-methylbutyl]biphenyl-4-carbonitrile. Optical parameters, such as wavelength-dependent transmittance and absorbance, were obtained with Ultraviolet/Visible spectroscopy. Dielectric parameters were also determined with dielectric spectroscopy. An increase in the value of dielectric constant for 1 kHz from 4.486 to 5.774 was observed with the increasing 4′-[(S)-2-methylbutyl]biphenyl-4-carbonitrile concentration. Moreover, an increase in optical band gap value from 3.791 to 3.801 eV was seen with increasing 4′-[(S)-2-methylbutyl]biphenyl-4-carbonitrile concentration. Results indicated substantial changes in optical and dielectric parameters depending on chiral dopant concentration. In this regard, it is considered that current study will contribute insight to scientists who continue their research on optical and dielectric characterizations of cholesteric liquid crystal-based composites and its technological applications.

Source/drain contact resistance (R_SD) is a decider of device performance in nanoscale indium–gallium–zinc–oxide (IGZO) transistors, especially in the ones featuring a vertical channel. In this work, titanium nitride (TiN), prepared by magnetron sputtering (MS) and ion beam sputtering (IBS), is adopted as the S/D electrodes of vertical channel-all-around (VCAA) IGZO transistors, and the contact properties are revealed. Both MS-TiN and IBS-TiN form Schottky contacts on IGZO, strongly limiting the ON-state current (I_ON) of VCAA IGZO devices with a 50 nm gate length. Such Schottky contacts result from metal oxidation during the atomic layer deposition (ALD) process of IGZO. IBS-TiN/IGZO shows a lower R_SD of 7.41 × 10⁻² MΩ as compared to MS-TiN/IGZO with an R_SD of 2.15 MΩ. The two kinds of TiN have an almost equal work function (φ_WF) of around 4.7 eV, the lower R_SD of IBS-TiN/IGZO is derived from the reduced tunneling resistance rather than Schottky barrier resistance. IBS-TiN appears denser with no detectable intergranular porosity whereas MS-TiN presents a typical microstructure comprising coarse and columnar grains with visible intercolumnar porosities, making IBS-TiN more robust against oxidation than MS-TiN. Also, the higher N/Ti ratio in IBS-TiN strengthens its antioxidation characteristic to some extent.

Metal–organic frameworks (MOFs) possess great potential for detecting toxic gases for environmental remediation and developing clean energy storage systems. Herein, two porphyrin-based MOF composites (Zn-TCPP@PVP and Ni-TCPP@PVP) were synthesized and successfully applied for selective detection of ammonia and supercapacitor applications. M-TCPP@PVP (M = Ni, Zn) polymer composite MOFs are controllably synthesized using Ni and Zn metal ions and TCPP (tetrakis-(4-carboxyphenyl) phosphonium porphyrin) organic linker in presence of polyvinyl pyrrolidone (PVP) modulator. All prepared materials were characterized by XRD, FT-IR, SEM, BET and XPS techniques. The obtained M-TCPP@PVP (M = Ni, Zn) composites were used as a sensing materials for ammonia, formaldehyde, ethanol, and acetic acid. The Ni-TCPP@PVP composite exhibits twofold more sensing activity towards ammonia gas than the Zn-TCPP@PVP composite at 50 ppm, with sensing response of 61 and 32.7 respectively. In addition, M-TCPP@PVP (M = Ni, Zn) MOFs with excellent surface area, high electrical conductivity and thermal stability, have been explored for supercapacitor applications. In a three-electrode measurement, Ni-TCPP@PVP composite delivered high specific capacity of 205 C g⁻¹, whereas Zn-TCPP@PVP composite delivered only 98 C g⁻¹ at a current density of 1 A g⁻¹. Moreover, the as-fabricated symmetric supercapacitor device (left(text{Ni}-text{TCPP}@text{PVP}Vert text{Ni}-text{TCPP}@text{PVP}right)) utilizing Ni-TCPP@PVP material delivers a maximum energy density of 12 Wh kg⁻¹ and power density of 3770 W kg⁻¹. The present study explores the potential of porphyrin-based M-TCPP@PVP (M = Ni, Zn) MOFs for the detection of toxic gases and for the next generation charge storage applications.