Journal of Electronic Materials最新文献

Temperature and humidity are the two critical external parameters that substantially influence the efficiency of dye-sensitized solar cells (DSSCs). The performance of DSSCs is reliant upon several factors, including electrolyte characteristics, the dye applied on the semiconductor, and charge separation. Temperature and humidity may impact DSSCs in various ways in terms of their structural and mechanistic quality, hence affecting their performance. This work involved the testing of DSSCs under diverse temperature and humidity settings. The power conversion efficiency (PCE) of the DSSCs was notably reduced by about 28% when the temperature rose from 25°C to 60°C and by about 39% when both temperature and humidity were elevated simultaneously from 25°C to 60°C and from 75% to 100%, respectively. Elevated temperatures and humidity circumstances may result in dye degradation and desorption from the semiconductor, electrolyte degradation, and an increase in charge recombination, finally affecting the J_SC and diminishing the device’s overall performance. This study will facilitate potential commercialization of DSSCs in actual weather circumstances.

Tb-activated phosphors are crucial for achieving narrow-band green emission in modern optoelectronic devices, but their thermal and chemical instability under high power restricts practical application. In this study, we prepared a Sr_0.97Ba_0.02Ga₂O₄:0.01Tb³⁺ phosphor featuring low thermal quenching, which retains 80% of its initial luminous intensity even at 210°C. Partial substitution of Sr²⁺ with Ba²⁺ introduces more polar and rigid bonds, significantly enhancing thermal stability; first-principles elastic modulus calculations corroborate this structural stiffening effect. The sample’s structure, morphology, and optical properties were characterized: x-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy confirm a highly pure phase with space group P21/c and a Ga-O stretching vibration at 679 cm⁻¹. Under 378-nm excitation, the green emission intensity at 543 nm is nearly tripled compared to Sr_0.99Ga₂O₄:0.01Tb³⁺, with CIE color coordinates of (0.2731, 0.4789). These results demonstrate the promising application potential of this phosphor for solid-state lighting and provide theoretical support for the site substitution mechanism. The material was synthesized using a high-temperature solid-state method and is compatible with near-ultraviolet (UV) chips, making it suitable for high-power light-emitting diodes/micro-light-emitting diodes (LEDs/µLEDs), display backlighting, and automotive lighting applications.

This study provides a comprehensive analysis of cesium (Cs)-doped cobalt oxide (Co₃O₄) thin films for carbon monoxide (CO) detection. These films were prepared using spray pyrolysis with Cs content of 1–5 wt.% and were characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), photoluminescence (PL) spectroscopy, and ultraviolet–visible (UV–Vis) spectroscopy. XRD analysis confirmed that the cubic spinel phase was preserved and the crystallite sizes decreased nonlinearly from 77.3 nm to 54.9 nm with increasing Cs content, whereas FESEM showed a morphological evolution from triangular to disordered structures. PL spectra revealed enhanced defect-related emissions with an increase in Cs concentration. Electrical measurements showed that 3 wt.% Cs-doped film exhibited the best conductivity and optimal performance for CO detection at 200°C and exhibited a nearly linear response (R² = 0.988) from 65 ppm to 500 ppm, with a detection limit of 65 ppm. These results indicate that Cs doping can fine-tune the microstructure, defect density, and charge transport for improving the sensitivity and selectivity of Co₃O₄-based CO sensors for environmental monitoring applications.

Solid polymer electrolytes (SPEs) are attractive options for next-generation energy storage systems owing to their safety, versatility, and cost-effectiveness. However, their low ionic conductivity makes them unsuitable for practical use. This study created a new chitosan (CS)-dextran (Dx) blend SPE containing ammonium thiocyanate (NH₄SCN) and zinc oxide (ZnO) nanoparticles. The SPE was plasticized with different glycerol concentrations (8–40 wt%). The films were created via solution casting and rigorously examined to determine the effect of glycerol on structural, physicochemical, dielectric, and electrochemical performance. x-Ray diffraction (XRD) revealed a mostly amorphous structure, with crystallinity decreasing linearly from 25.32% to 18.63%. The Fourier transform infrared (FTIR) analysis confirms the successful incorporation of chitosan, dextran, ammonium thiocyanate, and ZnO nanofillers via characteristic vibrational bands, while the ion transport parameters (ionic conductivity, mobility, diffusion coefficient, and transference number) showed increased ion migration and charge carrier contribution within the composite polymer–electrolyte system. Electrochemical impedance spectroscopy (EIS) revealed a considerable decrease in bulk resistance from 167.8 kΩ to 104 Ω, which resulted in an increase in ionic conductivity from 0.025 µS·cm⁻¹ to 62.43 µS·cm⁻¹, over 2500-fold. Dielectric investigations revealed that the dielectric constant increased from 1.6 × 10³ to 9.5 × 10⁴, while dielectric loss increased from 1.2 × 10² to 8.0 × 10³, indicating enhanced dipolar relaxation and interfacial polarization. Furthermore, relaxation time dropped from 35.15 µs to 0.67 µs, indicating quicker ion dynamics and efficient dielectric response at greater glycerol concentrations. The combination of glycerol plasticization and ZnO nanoparticle reinforcement produced flexible, highly amorphous, and ionically conductive membranes with improved dielectric performance. These results show that CS–Dx–NH₄SCN–ZnO–glycerol composites are cost-effective, high-performance SPEs for sustainable energy storage applications.

Charge storage based on anion intercalation is far less common than processes involving cation intercalation. Recently, oxide-anion-based charge storage has been demonstrated in some oxide materials through a pseudocapacitive process. In this work, quasi-two-dimensional (2D) oxides with the formula LaSrMn_0.5M_0.5O₄ (M = Co, Ni) were investigated with respect to their pseudocapacitive charge storage properties. The two materials are isostructural and comprise 2D layers of BO₆ octahedra (B is a transition metal), separated by La/Sr. The pseudocapacitive charge storage, involving the intercalation and deintercalation of oxide ion, is facilitated by the wide gap between 2D layers. The diffusive and capacitive contributions to the observed current were analyzed. In addition, symmetric full cells were fabricated using both materials. At a current density of 0.5 A/g in a symmetric cell in 1 M KOH, LaSrMn_0.5Co_0.5O₄ and LaSrMn_0.5Ni_0.5O₄ showed respective specific capacitance values of 193 F/g and 60 F/g, and energy densities of 68 Wh/kg and 21 Wh/kg, at a power density of 1600 W/kg. Importantly, compared to other anion-based charge storage systems, LaSrMn_0.5Co_0.5O₄ shows remarkable specific capacitance and energy density values, which are superior to those of many previously reported pseudocapacitors operating based on oxide intercalation. This material also shows very stable performance, retaining its specific capacitance even after 10,000 charge–discharge cycles.

A first-principles study was conducted to investigate the structural, optoelectronic, and thermoelectric properties of Sc₂SrX₄ (X = S, Se) chalcogenides in the tetragonal I-42d space group. The ground-state properties were computed using the Tran–Blaha modified Becke–Johnson potential (TB-mBJ) potential. The phonon dispersion and ab initio molecular dynamics (AIMD) study confirmed the dynamic stability of the materials. The formation energy per atom (eV) of the Sc₂SrS₄ and Sc₂SrSe₄ materials was found to be −2.12 and −2.51, respectively. The electronic study predicted a direct-bandgap semiconducting nature of the materials. The energy bandgaps of Sc₂SrS₄ are 1.1 eV (Perdew–Burke–Ernzerhof generalized gradient approximation [PBE-GGA]) and 1.5 eV (TB-mBJ), and those of Sc₂SrSe₄ are 0.8 eV (PBE-GGA) and 1.2 eV (TB-mBJ). The optical parameters were computed in the energy range of 0–14 eV. The highest values of ε₁(ω) and ε₂(ω) in the visible region of the optical spectrum make the materials attractive candidates for photovoltaic applications. The Seebeck coefficients suggest that Sc₂SrS₄ displays n-type behavior at low temperatures and p-type at higher temperatures, and Sc₂SrSe₄ demonstrates n-type semiconducting behavior. Thermoelectric analysis indicates that Sc₂SrS₄ exhibits higher electrical and electronic thermal conductivity when compared to the Sc₂SrSe₄ material.

Folic acid-coated zinc ferrite (ZnFe₂O₄) nanoparticles were integrated into a polyvinyl alcohol (PVA) matrix through solution casting. The objective was to modify the properties of PVA at a minimal concentration of nanoparticles while preventing agglomeration. X-ray diffraction analysis confirmed the presence of the incorporated phases, and changes in the hydrodynamic size of the FA-ZnFe₂O₄ nanoparticles were observed via zeta sizing. Fourier transform infrared spectroscopy verified the presence of the folic acid coating. Ultraviolet–visible spectroscopy showed a redshift in optical absorption and notable alterations in the direct bandgap (5.44 eV to 4.92 eV). Furthermore, changes in the Urbach energy (0.48 eV to 0.70 eV), extinction coefficient (1.78 × 10⁻⁴ to 5.24 × 10⁻³ at 400 nm), refractive index (1.18 to 2.64 at 270 nm), and optical conductivity (2.88 × 10⁹ S⁻¹ to 1.34 × 10¹¹ S⁻¹ at 400 nm) were documented. Additionally, frequency-dependent electrical analysis indicated an increase in the dielectric constant (1.02 to 3.8 at 1 MHz), a decrease in the dielectric loss (5.39 to 2.99 at 10 MHz), and an enhancement in AC conductivity (8.11 × 10⁻⁴ S m⁻¹ to 1.52 × 10⁻³ S m⁻¹). These films have potential applications in wide-bandgap UV-photodetectors and dielectric devices.

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The structural and magnetic properties of a polycrystalline Dy_0.4Sm_0.6FeO₃ compound synthesized via the sol–gel route and sintered at 800°C, 1000°C and 1200°C are elucidated in this paper. X-ray diffraction (XRD) analysis with Rietveld refinement confirms that the samples sintered at 800°C and 1000°C exhibit a single phase without any detectable impurity. The M–H hysteresis shows an increase in magnetization with increasing sintering temperature. Mössbauer spectra reveal a slight increase in the hyperfine field with sintering temperature, indicating improved magnetic ordering. The observed smaller isomer shift suggests the presence of the Fe³⁺ state. Overall, the sample sintered at 1000°C exhibits comparatively superior properties.

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This study explores a scalable strategy for enhancing the optical and dielectric performance of nematic liquid crystals (NLCs) through photolithographic micro-patterning and gold nanoparticle incorporation. Traditional rubbing techniques for LC alignment suffer from limited precision and repeatability; to address this, we fabricated microgrooves (2 × 10 µm) on indium tin oxide (ITO) substrates using photoresist thin films to induce uniform, anisotropic alignment. Polarized optical microscopy (POM) confirmed that these micro-patterned substrates provide superior alignment control compared to conventional methods. To further enhance the electro-optic response, spherical gold nanoparticles (AuNPs) and anisotropic gold nanorods (AuNRs) were integrated into the LC system. AuNPs were deposited within the microgrooves, while AuNRs were doped into the NLC bulk. This combined approach led to a measurable improvement in dielectric and optical properties. Specifically, the threshold voltage was reduced by ~ 18%, while the dielectric loss factor (tan δ) decreased by ~ 25% for AuNP-doped systems and ~ 32% for AuNR-doped systems. Moreover, the AuNR-enhanced system demonstrated a ~ 40% reduction in optical switching time compared to pure NLCs, indicating improved molecular alignment and faster electro-optic response. These findings highlight the combined influence of micro-pattern engineering and plasmonic nanomaterials in enhancing liquid crystal performance. The approach offers tunable dielectric anisotropy, lower energy consumption, and improved switching dynamics, establishing a promising platform for advanced applications in photonics, low-voltage display technologies, and optical sensing devices.

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Micro-patterned NLC devices integrated with Au nanorods exhibit enhanced optical switching and dielectric properties, enabling precise LC alignment. These advancements pave the way for scalable applications in photonics, biosensing, and optoelectronic technologies.

Although Sn58Bi solder offers numerous advantages, including a low melting point, its poor ductility and reliability hinder its widespread application in the electronics industry. Nanoparticles exhibit excellent performance as reinforcements, and ceramic nanoparticles in particular have been widely investigated as additives for Sn58Bi solders because of their low cost and high chemical stability. However, most previous studies have focused primarily on mechanical strength rather than ductility. In this study, we assessed the effect of MoS₂ nanoparticle addition on reliability by calculating the fracture energy, which reflects both strength and ductility. We prepared composite Sn58Bi solders incorporating different quantities of MoS₂ nanoparticles, defined as Sn58Bi-xMoS₂ (where x = 0, 0.1, 0.2, 0.3 wt.%), and subjected them to different durations of isothermal heating to investigate the resulting changes in the melting point, microstructure, hardness, and shear properties. The MoS₂ nanoparticle content did not significantly affect the melting point of the Sn58Bi solder, but improved its other properties considerably. The incorporation of MoS₂ nanoparticles significantly refined the solder microstructure, reduced the average interphase spacing in Sn58Bi-0.2MoS₂ by 38.5% compared with that of pure Sn58Bi solder, reduced the interfacial intermetallic compound thickness, and substantially improved the solder hardness, shear strength, and fracture energy. The results of this study support the incorporation of MoS₂ nanoparticles in Sn58Bi solder to realize safe and effective soldering in electronic packaging applications.

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