Vacuum-processed perovskite light-emitting diodes (PeLEDs) hold great promise for large-area, high-resolution display technologies owing to their compatibility with scalable patterning and fabrication processes. However, their performance has been constrained by interfacial defects that induce non-radiative recombination losses. Herein, we demonstrate highly efficient and stable CsPbBr3-based PeLEDs fabricated via evaporation through a multi-functional interfacial engineering strategy that enables comprehensive defect passivation. A synergistic combination of phenylethylammonium bromide (PEABr), lithium bromide (LiBr), and (2-(3,6-dibromo-9H-carbazol-9-yl)ethyl)phosphonic acid (Br-2PACz) is introduced to concurrently suppress halide vacancies, modulate crystallization kinetics, and passivate trap states in perovskite. Time-resolved photoluminescence and space-charge-limited current analyses further confirm the prolonged exciton lifetime and reduced defect density. This cooperative effect enhances radiative recombination and carrier balance, resulting in a record external quantum efficiency (EQE) of 9.46% and a peak luminance of 21,931 cd m-2, representing similar to 135- and 49-fold improvements compared with the pristine device (0.07% EQE and 446.7 cd m-2). Moreover, the optimized PeLED exhibits a 15.8-fold increase in operational lifetime (from 15.5 to 245.7 min at 100 cd m-2) and markedly reduced current hysteresis, attributed to suppressed ion migration and stabilized interfacial energetics. This work highlights an effective pathway toward realizing vacuum-processed, high-performance perovskite emitters through rational multi-functional interface design.

In this study, we fabricated high-performance green quantum dot light-emitting diodes (QLEDs) by introducing NiMgLiO thin films as optimized hole injection layer materials, deposited via radio frequency sputtering. The NiO matrix was co-doped with Mg and Li to modulate its electronic structure and enhance its charge transport properties. This co-doping approach substantially increased the Ni3+ ion concentration and deepened the valence band maximum, thereby reducing the hole injection barrier and improving the electrical conductivity of the NiO films. These modifications were associated with improved device performance, consistent with improved charge balance within the QLED. Consequently, the external quantum efficiency of the QLEDs increased from 6.83% to 9.02%, while the maximum luminance rose from 41711 to 57636 cd/m(2). To the best of our knowledge, these values are the highest reported among sputtered NiO-based green QLEDs to date. Overall, this study demonstrates that co-doping with Mg and Li, in combination with a scalable sputtering process, offers a robust strategy for tuning the electrical and optical properties of oxide-based HILs, thereby advancing the development of high-efficiency, stable QLED technologies.

Quantum dot light-emitting diodes (QLEDs) hold immense potential for next-generation display technologies, yet their progress has been hampered by the lack of efficient inorganic hole-injection layers (HILs), which typically suffer from poor energy-level alignment and interfacial traps. Herein, a powerful interfacial engineering strategy is reported that transforms the performance of inorganic HILs by integrating Cu-doped NiO (Cu:NiO) with halide-functionalized self-assembled monolayers (SAMs) of (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz). Halide-SAMs induce strong dipoles that shift the Cu:NiO valence band to deeper levels, enhance hole density, suppress surface defects, and lower the hole-injection barrier into the hole-transport layer. Furthermore, density functional theory (DFT) calculations identify that the high polarizability of the halide substituents plays a decisive role. This high polarizability enhances van der Waals (vdW) dispersion forces, promoting robust molecular anchoring and the formation of a dense, stable passivation layer that effectively suppresses surface defects. Consequently, QLEDs incorporating I-2PACz-modified Cu:NiO achieve a record-high external quantum efficiency (EQE) of 26.95% (Mean 19.53%), a 3.5-fold improvement over unmodified devices. This represents the highest efficiency reported for green QLEDs employing inorganic HILs. This work demonstrates that simultaneously tuning interface polarity and molecular polarizability offers a viable pathway to trap-suppressed, charge-balanced, and high-performance QLED architectures.

In this study, the electrical characteristics, stability, and trap-state density of states (DOS) in IGTO thin-film transistors (TFTs) are analyzed based on the O2/(Ar + O2) ratio, and the relationship between carrier traps and device stability is investigated using photo-excited charge collection spectroscopy (PECCS). Thin film samples with varying O2/(Ar + O2) ratios are fabricated, and the electrical characteristics and trap-related binding energies of each sample are examined. In addition, the field-effect mobility, threshold voltage, and subthreshold swing of TFT devices with a 20 nm IGTO channel layer deposited under the same conditions are evaluated. The field-effect mobility gradually decreases as the O2/(Ar + O2) ratio increases, with the highest mobility of 37.3 cm2/Vs observed at an O2/(Ar + O2) ratio of 2 %. To evaluate device stability at different O2/ (Ar + O2) ratios, positive bias stress (PBS) and negative bias illumination stress (NBIS) are applied for 5000 s, and Delta Vth shifts are monitored. In addition, to compare with conventional InGaZnO (IGZO), a control TFT using IGZO deposited at the same thickness and O2/(Ar + O2) ratio (2 %) is also fabricated. Under PBS, Delta Vth values of 0.21 V and 1.57 V are observed at O2/(Ar + O2) = ratios of 2 % and 10 %, respectively. NBIS-induced Delta Vth is evaluated under various light wavelengths. Unlike IGZO, which shows strong UV sensitivity, IGTO exhibits responses across all wavelengths. The DOS is extracted from transfer curves obtained via PECCS to quantify the trap states. The highest trap density appeared in the red-light region with values of 4.83 x 1011 cm-2 eV-1 for both 2 % and 10 % O2/(Ar + O2) ratios. These results suggest that IGO traps more electrons in the red light region than the IGZO under similar conditions while showing fewer traps in the blue and UV regions. Furthermore, the impact of trap states on the NBIS stability is assessed by comparing the Delta Vth shifts with the DOS profile.

Zn x Mn 1.5-0.5x Co 1.5-0.5x O 4 (ZMCO) powders were synthesized using a solid-state method and applied to 460 FC stainless-steel interconnects via electrophoretic deposition for solid oxide fuel cell (SOFC) applications. A reduction-oxidation heat treatment at 800 degrees C was used to densify the coating while maintaining compatibility with SOFC operating temperatures. X-ray diffraction analysis confirmed the reversible phase transformation of ZMCO spinel into MnO and Co metal during reduction, followed by spinel reformation upon oxidation. EPMA results demonstrated the coating's effectiveness as a Cr diffusion barrier. The composition with x = 0.2 exhibited optimal electrical conductivity through enhanced small polaron hopping mechanism. Thermal expansion coefficient (TEC) measurements revealed excellent compatibility between the ZMCO coatings and conventional SOFC interconnect materials. These findings indicate that ZMCO coatings, particularly at x = 0.2, are promising candidates as protective layers for SOFC interconnects.

This study investigates the effects of introducing 0-5 mol% NaNbO3 (NN) seeds on the structural, microstructural, dielectric, ferroelectric, and piezoelectric properties of KNN-based lead-free piezoelectric ceramics. All samples with the final composition 0.96[0.95(K0.52Na0.48NbO3) - 0.05LiSbO3] - 0.04SrZrO3-CuO (KNNLS-SZ-C) were sintered at 1060 degrees C for 6 h. X-ray diffraction analysis revealed a perovskite single phase for 0-5 mol% NN seed contents, with a multiphase coexistence of tetragonal, orthorhombic, and rhombohedral structures. As seed content increased from 0 to 3 mol%, the rhombohedral fraction increased while tetragonal and orthorhombic fractions decreased. SEM micrographs showed abnormal grain growth at 1-2 mol% seeds, transitioning to normal grain growth beyond 3 mol%. Optimal piezoelectric and electromechanical properties including d33 = 323 pC/N, kp = 0.39 were obtained at 3 mol% NN seed, attributed to the favorable multiphase structure fraction and moderate grain size. This work elucidates the interplay between NN seed addition, phase fraction distribution, and microstructural development in tuning the piezoelectric performance of these lead-free ceramics.

Achieving high-performance quantum dot light-emitting diodes (QLEDs), which are promising candidates for next-generation displays, requires balanced charge injection in terms of electrons and holes while minimizing nonradiative recombination. In this study, to improve charge balance in QLEDs, we enhanced the electrical conductivity of the hole injection layer by depositing NiO:Li thin films via radio frequency sputtering under varying oxygen partial pressures. Furthermore, a self-assembled monolayer (SAM) made of 4-trifluoromethyl benzoic acid was introduced on the NiO:Li films to reduce the hole injection barrier and facilitate efficient hole transport. This SAM was also applied on top of the quantum dot layer to act as an electron blocking layer by increasing the electron injection barrier, thereby suppressing excessive electron injection. The optimized QLEDs exhibited a maximum external quantum efficiency of 9.41% and a peak luminance of 50,199 cd/m2. These findings demonstrate a viable strategy to enhance QLED performance via the synergistic modulation of charge injection and recombination dynamics.

This study investigates the reaction sintering behavior and phase development in the indium tin zinc oxide (ITZO) system with varying compositions (In:Sn:Zn atomic ratios of 4.4:1.2:4.4, 5.5:0.8:3.7, 7.6:0.8:1.6, and 9.0:0.3:0.7). The phase evolution during heating was monitored using high-temperature X-ray diffraction, while densification behavior was analyzed through thermomechanical analysis. Results revealed that multiple phases, including ZnO, SnO2, Zn(2-x)Sn(1-x)In2xO4 (ZTIO), and indium zinc oxide (IZO), coexist during the reaction sintering process, with their relative amounts varying with temperature and composition. The presence of intermediate and second phases significantly influenced the densification behavior, as increased intermediate phase volume leads to additional hetero-phase interfaces, impeding the densification process. Compositions with higher intermediate and secondary phase content showed delayed densification and lower final density, attributed to the increased fraction of hetero-phase contacts in lower In2O3 content compositions. This study provides insights into the relationship between phase development and densification behavior in multi-component oxide systems during reaction sintering.

Chromium poisoning in 460FC stainless steel interconnects significantly impairs the performance of solid oxide fuel cells. A dual-layer coating was developed to address this issue, combining a Cu1.25Mn1.65Fe0.1O4 spinel layer, applied via electrophoretic deposition, and a Cu-Mn metal layer, deposited using sputtering. This approach demonstrated high effectiveness, producing coatings with uniform thickness and precise elemental composition. The oxidation rate was investigated by analyzing the coating's mass gain. The dual-layer coating underwent a thermal transformation, re-establishing the CuMn2O4 spinel structure through metal diffusion and forming a thick oxide scale. After 1000 h at 800 degrees C, the area-specific resistance of the SUS/EPD/SM dual-layer coated sample demonstrated excellent conductivity at 5.76 m Omega cm2. Additionally, the SUS/EPD/SM dual-layer coating provides resistance to chromium poisoning, significantly reducing the chromium content diffusing from stainless steel to the surface compared to single-layer coatings produced by each method.

The effect of LiSbO3 and SrZrO3 doping on the piezoelectric characteristics of K0.5Na0.5NbO3-based ceramics was studied. First, (1 − x)K0.5Na0.5NbO3–xLiSbO3–CuO (0.00 ≤ x ≤ 0.07) was synthesized and a single phase of perovskite was observed in the range of 0.00 ≤ x ≤ 0.05. As LiSbO3 content increased, the orthorhombic single phase changed to orthorhombic and tetragonal multiphase. TO–T decreased from 176 °C (x = 0.00) to 85 ℃ (x = 0.05) and, the d33 showed the highest value of 156 pC/N (x = 0.05). Next, (0.95K0.5Na0.5NbO3–0.05LiSbO3)–xSrZrO3–CuO (0.00 ≤ x ≤ 0.05) was studied. All compositions were well synthesized as perovskite phases; orthorhombic and tetragonal mixed phases up to x = 0.02, rhombohedral, orthorhombic, and tetragonal mixed phases at x = 0.03 and 0.04; and rhombohedral and tetragonal phases at x = 0.05. TO–T decreased from 78 ℃ (x = 0.00) to 32 ℃ (x = 0.04), and TR–T was formed at 48 ℃ (x = 0.05). The d33 value at x = 0.04 was 288 pC/N and significantly reduced to 134 pC/N at x = 0.05.

The effect of LiSbO 3 and SrZrO 3 doping on the piezoelectric characteristics of K 0.5 Na 0.5 NbO 3 -based ceramics was studied. First, (1 − x)K 0.5 Na 0.5 NbO 3 –xLiSbO 3 –CuO (0.00 ≤ x ≤ 0.07) was synthesized and a single phase of perovskite was observed in the range of 0.00 ≤ x ≤ 0.05. As LiSbO 3 content increased, the orthorhombic single phase changed to orthorhombic and tetragonal multiphase. T O–T decreased from 176 °C (x = 0.00) to 85 ℃ (x = 0.05) and, the d 33 showed the highest value of 156 pC/N (x = 0.05). Next, (0.95K 0.5 Na 0.5 NbO 3 –0.05LiSbO 3 )–xSrZrO 3 –CuO (0.00 ≤ x ≤ 0.05) was studied. All compositions were well synthesized as perovskite phases; orthorhombic and tetragonal mixed phases up to x = 0.02, rhombohedral, orthorhombic, and tetragonal mixed phases at x = 0.03 and 0.04; and rhombohedral and tetragonal phases at x = 0.05. T O–T decreased from 78 ℃ (x = 0.00) to 32 ℃ (x = 0.04), and T R–T was formed at 48 ℃ (x = 0.05). The d 33 value at x = 0.04 was 288 pC/N and significantly reduced to 134 pC/N at x = 0.05.

Electrical conductivity is one of the most important concerns in spinel-structured antioxidant films coated on a solid oxide fuel cell separator, and the mechanism of electrical conduction involves the small polaron hopping through corner-shared octahedral sites. Arranging favorable ions in the octahedral sites rather than in the tetrahedral sites is better for achieving higher electrical conduction. In this study, Zn, which prefers the tetrahedral site, was substituted for the Mn1.5Co1.5O4 spinel to arrange site distribution. The crystal structure, electrical conductivity, and thermal expansion behavior of Zn-substituted ZMCOs [ZnxMn1.5-0.5xCo1.5-0.5xO4 (0.0 <= x <= 0.6)] were investigated. At Zn = 0.2, the highest electrical conductivity of 42.1 S/cm was observed, while at Zn > 0.2, the electrical conductivity decreased due to decreased Co2+/Co-III and Mn3+/Mn4+ pair concentration because Zn ions started to occupy the octahedral site. The higher the Zn concentration of ZMCO, the lower the distortion of the MnO6 octahedron via the Jahn-Teller effect, resulting in a higher symmetry of the crystal structure. Therefore, with the increase in the Zn concentration, a mixture of tetragonal-cubic phase changed to cubic phase. In addition, the phase transition temperature of the tetragonal-cubic phase decreased.

The transfer energy of oxygen vacancy of La and Y co-doped CeO2 is investigated in which the total amount of La and Y is fixed at 20 at%. Although both the La3+ (1.16 Å) and Y3+ (1.032 Å) ions are larger than the Ce4+ ions (0.97 Å), individual single doping of La and Y results in an increase and a decrease in the CeO2 lattice constant, respectively, due to the effect of the critical ionic radius (rc). As the La/Y ratio varies, the lattice constant increases as the La content increases, which leads to a decrease in the migration energy of the oxygen vacancy in the grain interior. When La and Y are co-doped at a ratio of 2:18, its lattice constant is almost the same as that of pure CeO2 in which the dissociation energy of the oxygen vacancy achieves the lowest value due to the minimum lattice-strain energy. The migration energy at the grain boundary also decreases with increasing La content. This result is explained by the degree of grain boundary segregation of the dopant.

As a protective coating of the interconnects in solid oxide fuel cells, spinel-structured Cu1.35Mn1.65O4 powder was coated onto 460FC stainless steel by using the electrophoretic deposition method. A suitable amount of iodine was added to ethanol to charge the spinel powder with a high zeta potential value. Stainless steel substrates were immersed in a slurry, and a DC voltage in the range of 20-60 V was applied for 30-120 s. Because a low-temperature densification of the coated film is crucial for minimizing Cr out-diffusion from the stainless steel substrate, the coated spinel was decomposed into Cu and MnO by applying a heat treatment at 800 degrees C in a 5% H-2/95% N-2 atmosphere. Then, it was oxidized at 700 degrees C in air, leading to appropriate densification. The area-specific resistance of the films was 15-29 m Omega cm(2) after 1000 h at 700 degrees C in air. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

High-k Y₂O₃ thin films were investigated as the gate dielectric for amorphous indium zinc tin oxide (IZTO) thin-film transistors (TFTs). Y₂O₃ gate dielectric was deposited by radio frequency magnetron sputtering (RF-MS) under various working pressures and annealing conditions. Amorphous IZTO TFTs with SiO₂ as the gate dielectric showed a high field-effect mobility (μFE) of 19.6 cm²/Vs, threshold voltage (Vth) of 0.75 V, on/off current ratio (Ion/Ioff) of 2.0×106, and subthreshold swing (SS) value of 1.01 V/dec. The IZTO TFT sample device fabricated with the Y₂O₃ gate dielectric showed an improved subthreshold swing value compared to that of the IZTO TFT device with SiO₂ gate dielectric. The IZTO TFT device using the Y₂O₃ gate dielectric deposited at a working pressure of 5 mtorr and annealed at 400 °C in 6 sccm O₂ for 1 hour showed a high μFE of 51.8 cm²/Vs, Vth of -0.26 V, Ion/Ioff of 6.0×10³, and SS value of 0.19 V/dec. With the application of a Y₂O₃ gate dielectric, the Vth shift improved under a positive bias stress (PBS) but was relatively unaffected by negative bias stress (NBS). These shifts were attributed to charge traps within the gate dielectric and/or interfaces between the channel and gate dielectric layer.

Full densification of the interconnector La0.8Ca0.2Cr0.9Co0.1O3-delta (LCCC) layer is hardly achieved when it is screen-printed and cofired on a pre-sintered NiO-YSZ (yttria-stabilized zirconia, 8YSZ) substrate. In this study, the LCCC precursors with different concentrations and viscosities were prepared and infiltrated into the LCCC-YSZ layer. The phase development process and densification behavior of the LCCC were analyzed, and the optimum conditions for full densification are suggested. Through the research, we propose a method for manufacturing a dense LCCC interconnector layer.

The densification behaviour and phase development of Y2O3 ceramics were investigated as a function of yttrium nitrate (Y(NO3)3·6H2O) solution addition during the cold sintering process at 200 °C. Second phases such as Y4O(OH)9NO3 and Y(OH)3 were observed after the cold sintering process. The amount of Y4O(OH)9NO3 increased with increasing amount of yttrium nitrate, while the amount of Y(OH)3 decreased. The second phases were transformed to fine sized Y2O3 (∼30 nm) particles smaller than those of the raw powder (<400 μm) by sintering at 600 °C. The fine sized Y2O3 particles were located in the voids between the larger Y2O3 particles, thus increasing the packing density and enhancing the densification of the Y2O3 ceramics after the final sintering process.

Hydroxyapatite (HA) was synthesized through the precipitation method and different processing parameters (Ca/P molar ratio, pH, and reaction temperature) were varied to investigate their influence on the HA formation. No HA powder was obtained at pH 10 and 25 °C, even when using a Ca/P ratio as high as 2.2. However, HA powders were successfully produced at pH above 11, 25 °C, and Ca/P ratio of 2.2. At pH 10 and 25 °C, the concentration of the H + ions in the reaction solution increased and so did the Ca loss, resulting Ca-deficient hydroxyapatite (CdHA) formation. While HA was formed instead due to a lower Ca loss when the pH was increased to 11 and 11.3. As the reaction temperature was increased to 70 and 90 °C, the HA formation occurred regardless of the pH because of the decreased solubility of HA in the solution.

Full densification of Y2O3 is challenging and requires a very high sintering temperature (above 1700 degrees C). In this study, the effect of ZnO and TiO2 dopants on its densification was investigated, showing that both dopants lowered the sintering temperature and improved the process. Moreover, ZnO promoted the grain growth, while TiO2 inhibited it; hence, the ZnO-TiO2 co-doping and the change in the ZnO/TiO2 ratio allowed the control of the sintered body microstructure while maintaining high densification. Since Y2O3 has a higher plasma erosion resistance than conventional Si-based materials, the plasma dry etching resistance of the sintered Y2O3 was also evaluated and found superior due to the improved densification and controlled grain size of the doped samples.

In this study, we investigated the characteristics of densification, phase formation, and electrical properties during reaction sintering when a Ga-doped ITO, with 10 at% Sn, served as the target material. Results showed that Ga doping enhanced the densification of ITO at a relatively low sintering temperature. Interestingly, the 1 at % Ga- and 20 at% Ga-doped samples showed shrinkage values of 19.5% and 23.0%, respectively, despite the fact they both starting shrinking at the same temperature. In addition, the second phase Ga3-xIn5+xSn2O16 was formed at 5 at% Ga-doped ITO. Moreover, the ITO lattice parameters decreased up to 40 at% Ga doping, since the ionic radius of Ga3+ is smaller than that of In3+. Furthermore, as the Ga concentration increased, the carrier concentration and mobility decreased and resistivity increased. These modifications are thought to result from an increasing quantity of the Ga3-xIn5+xSn2O16 s phase and the corresponding resistivity increase, both of which occur as a function of increasing Ga concentration.