Journal of Materials Science: Materials in Electronics最新文献

Industrial organic dye releases have generated serious environmental and health issues. Research on sustainable and energy-efficient water treatment systems employing semiconductor photocatalysts to turn sunlight into chemical energy to break down environmental pollutants has been conducted. We carefully created platelet-shaped thin films of strontium titanate (SrTiO₃) with a distinct triplet-phase structure. These innovative materials are designed to improve wastewater treatment efficiency, making them a potential water purification option. Diffraction peaks in the XRD pattern revealed the existence of triplet-phase patterns (SrO, TiO and SrTiO₃), confirming nanocomposites’ development. FE-SEM pictures showed three phases formed with composite formation on the surface with platelet-shaped particles, according to XRD data. SrTiO₃ composites exhibit significant UV absorption and visible transmittance in UV–Vis spectra. Additional support for SrTiO₃ nanocomposites in the films came from XPS spectra. Composites at 350, 400 and 450 °C degraded MB dye more effectively than bare ones under sunlight. This may be due to the composite’s optimised electron–hole pair recombination and charge transport. The study found that substrate temperature influences the microstructure, optical, functional, compositional, emission and electrical properties of SrTiO₃ composite films for environmental applications.

Quantum dot-sensitized solar cells (QDSSCs) are equipped with counter electrodes (CEs) based on reduced graphene oxide (rGO) and nickel sulfide (NiS/rGO). A hydrothermal method performed at 150 °C with variable reaction times (5, 10, and 15 h) was used to synthesize NiS/rGO CEs and evaluate their electrocatalytic activity and stability by exposing them to varying conditions at 25, 40, 60, and 80 °C for 100 h. Electrochemical performance was assessed through cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization. Results showed that NiS/rGO 5 h exhibited superior electrocatalytic activity, achieving a significantly higher current density. CV results showed that NiS/rGO 5 h generated the highest current density of 112.4 mA/cm² at 80 °C (Pt = 8.1 mA/cm²), and lower charge-transfer resistance (R_ct values, 3.6 Ω cm² at 80 °C than (Pt = 674.4 Ω cm²). The high performance was attributed to the dominance of β-NiS phase. Additionally, the nanocomposites demonstrated strong mechanical adhesion and stability under prolonged exposure to elevated temperatures. This study highlights the potential of NiS/rGO nanocomposites as cost-effective and efficient alternatives to Pt for improved QDSSC performance.

This report elucidates fundamental insights into the optical and electrochemical performance of l-alanine-functionalized stable cadmium sulfide (CdS) quantum dots (QDs). Al-CdS QDs were efficiently synthesized via a simple, one-step wet chemical route. Powder XRD measurements revealed the cubic phase with a well-reduced crystallite size, high crystallinity, and phase purity of the synthesized material. SEM analyses showed nearly monodispersed spherical particles with a moderate porous architecture. FTIR spectra confirmed the efficient attachment of l-alanine onto the CdS surface. UV–Visible absorption spectra revealed the quantum size effect by a blue shift. The optical band gap of 3.64 eV was revealed from Tauc’s plot. PL spectra implied the presence of surface defects facilitating enhanced electrochemical activity. Pseudocapacitive activity was examined through analyses on CV and EIS measurements which were taken on a three-electrode system. The analyses revealed a hybrid charge storage behavior. The Al-CdS electrode exhibits a specific capacitance of 692 mF/g at 10 mV/s in 0.5 M Na₂SO₄ aqueous electrolyte. The observed hybrid charge storage behavior and surface-dominated pseudocapacitance highlight the potential of Al-CdS QDs as a model system for fundamental electrochemical studies and future composite electrode design.

Sol–gel, a chemical solution deposition method, is widely used for preparing advanced materials due to its low fabrication cost, stoichiometric control, and compatibility with large-area thin film fabrication without the need for high vacuum environment. One such material is lead lanthanum zirconate titanate (PLZT) which is ferroelectric in nature, but its film properties are highly sensitive to the preparation method of the precursor solution (Sol). Achieving consistent and repeatable film properties remains a significant challenge for device applications. In this study, three distinct sol–gel based solution routes were employed to prepare PLZT “Sols”: (i) open beaker method (Sol1), (ii) reflux method (Sol2), and (iii) reflux with distillation method (Sol3). From each “Sol,” a set of three films were prepared under identical conditions (nine films total) and evaluated for structural and ferroelectric properties to assess the impact of “Sol” preparation method and the repeatability within each set. One representative sample from each set was further selected for detailed analysis of surface morphology and elemental composition. The results demonstrate that “Sol” chemistry has a pronounced impact on film quality and repeatability. “Sol3,” prepared using the reflux with distillation method provided a more controlled chemical environment, yielding a uniform and stable solution thereby resulting in films with improved crystallinity, uniform surface morphology, and stoichiometry closest to the target composition. Moreover, Sol3 films exhibited enhanced ferroelectric behavior, including the highest saturation (~ 50 µC/cm²) and remnant (~ 15 µC/cm²) polarizations, along with a low leakage current density ~ 10⁻⁹ A/cm². “Sol3” proved to be a more reliable route for achieving better properties and repeatable results compared to “Sol1” and “Sol2.”

Eu³⁺-doped Bi₆Ti₃WO₁₈ (BTW) phosphors were synthesized via solid-state reaction route and systematically investigated to understand their structural and photoluminescent properties, with relevance to solid-state lighting and optical thermometry. X-ray diffraction (XRD) indicated the formation of a single-phase orthorhombic Aurivillius structure with space group A21am. Scanning electron microscopy (SEM) revealed agglomerated surface morphology, while the Fourier transform infrared (FT-IR) analysis confirmed the presence of characteristic metal–oxygen vibrational modes. The optical bandgap was estimated from UV–Vis diffuse reflectance spectra (DRS). Under 466-nm excitation, the Eu³⁺-doped BTW phosphors exhibited intense red emission centered at 615 nm, arising from the dominant ⁵D₀ → ⁷F₂ transition, along with CIE coordinates (0.643, 0.352), very high color purity and a low correlated color temperature. Time-resolved photoluminescence (TRPL) exhibited bi-exponential behavior, and temperature-dependent PL (TDPL) measurements demonstrated good thermal stability with 68.7% emission retained at 443 K with an activation energy of 0.267 eV. An FIR-based ratiometric thermometry yielded a maximum relative sensitivity of 1.16% K⁻¹. Overall, the obtained results demonstrate favorable chromaticity, good thermal stability, and effective temperature-sensing behavior in Eu³⁺-doped Bi₆Ti₃WO₁₈ phosphors.

Cu₂NiSnS₄ (CNTS) powder was successfully synthesized via a simple and cost-effective hydrothermal method. The influence of deposition time on their structural, morphological, optical, and electrical characteristics was comprehensively investigated. X-ray diffraction and Raman spectroscopy analyses confirmed that extended hydrothermal deposition enhances crystallinity and phase purity, eliminating secondary phases. The optical band gap of the CNTS varied with deposition time, ranging from 1.26 to 1.96 eV, reflecting changes in microstructural order and composition. Surface morphology and elemental analysis using SEM and EDX revealed that optimized stoichiometry was achieved at longer reaction durations, indicating that hydrothermal time critically affects uniformity and composition. Photoelectrical studies demonstrated that the CNTS powder prepared for 24 h (CNTS-24) exhibited the highest photocurrent and electrical conductivity, signifying improved charge transport and light-harvesting efficiency. Overall, the results highlight that the hydrothermal reaction time is a key parameter governing the crystallinity, stoichiometry, and photoresponse behavior of CNTS, establishing 24 h as the optimal duration for efficient solar cell applications.

Due to the suppression of band-edge Auger recombination, lead selenide (PbSe) is a critical material for uncooled infrared detection at room temperature. However, the optoelectronic performance of PbSe detectors exhibits significant temperature sensitivity, often deviating from room-temperature characteristics when operated in cryogenic environments. In this study, we fabricated PbSe photodetectors via vapor phase deposition (VPD) with both unpatterned and patterned architectures to evaluate their compatibility with standard microfabrication processes and their intrinsic temperature-dependent behaviors. Unpatterned devices on sapphire substrates demonstrate superior performance, achieving responsivity up to 2.52 A/W and specific detectivity of 1.52 × 10¹⁰ Jones at 2700 nm. In contrast, patterned devices on Si/SiO₂ substrates suffered significant performance degradation due to process-induced surface defects. Temperature-dependent measurements on unpatterned devices reveal a non-monotonic photocurrent trend, with a peak in the 150–200 K range. This phenomenon is attributed to the synergistic competition among thermally activated transport, lattice scattering, and phonon-assisted indirect Auger recombination. These findings highlight the critical role of device architecture and processing conditions in preserving the intrinsic properties of VPD-grown PbSe and provide guidance for optimizing the performance of cryogenic infrared detection systems.

K_0.47Na_0.47Li_0.06NbO₃ + (0.4 wt%) Bi_0.5Na_0.5ZrO₃ (KNLN + 0.4 wt% BNZ) lead-free ceramics were investigated to understand the influence of sintering temperature on their structural, electrical, ferroelectric, and optical performance. A stable morphotropic phase boundary was observed over a wide sintering range, accompanied by systematic grain growth and enhanced crystallinity. Electrical and dielectric analyses revealed non-Debye relaxation with a broad distribution of relaxation times, indicating complex charge-transport dynamics. The ceramic sintered at 1050 °C exhibited optimal ferroelectric behavior with enhanced polarization and a moderate coercive field, while leakage conduction was dominated by space-charge-limited transport. Photoluminescence studies showed a sintering-induced transition from shallow to deep defect emission, enabling tunable near-infrared luminescence. These results demonstrate that controlled sintering effectively tailors the multifunctional properties of KNLN + 0.4 wt% BNZ ceramics, highlighting their potential for lead-free ferroelectric and optoelectronic applications.

This study investigates the design, fabrication, and characterization of two-terminal fractional capacitors (FCs) with orders exceeding 0.35 and exceptional thermal stability. To achieve this, a nanocomposite of carbon nanotubes and AD-SiO₂ nanoparticles dispersed in epoxy is used as a dielectric. The devices exhibit fractional orders (0.3 < α < 0.85) and maintain stable fractance from − 15 °C to 136 °C, far exceeding the thermal limits of CNT-only FCs (− 15 °C to 40 °C) and those of capacitors reported in the GM-tube literature. This FC (α = 0.85, ({C}_{alpha }=84text{hspace{0.17em}}mu {text{Fs}}^{1-alpha })) showed full-range impedance stability, marking it as the first high-temperature FC for radiation instrumentation. Modeling and experiments confirm strong correlations between material composition and electrical behavior. In addition, this FC, integrated into a GM preamplifier yields a stable cutoff frequency ({omega }_{c}=(1/R{C}_{alpha }{)}^{1/alpha }) from 25 to 125 °C, achieving noise suppression unattainable with conventional RC filters. Further, it introduces the first fractional-order GM-tube model linked to ion-drift memory through Mittag–Leffler dynamics. By unifying high-temperature FO devices, a physically grounded GM model, and thermally robust FO filtering, this study establishes FCs as reliable components for nuclear and high-temperature applications.