- 标题
- 摘要
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- 实验方案
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Functionalization of the transition metal oxides FeO, CoO, and NiO with alkali metal atoms decreases their ionization potentials by 3–5 eV
摘要： The existence and stabilities of various neutral metal oxides of formula MON and MON2 (M = Fe, Co, Ni; N = Li, Na) and their corresponding cations MON+ and MON2+ are predicted using density functional theory (B3LYP) with the 6-311 + G(d) basis set. Ab initio calculations carried out at the CCSD(T)/6-311 + G(3df) level of theory reveal that the ionization potentials (IPs) of the oxides MO decrease by ca. 3–5 eV upon functionalization with N to give either MON or MON2. The influences of the chemical constitution and local spin magnetic moment (on the transition metal atom) of the oxide or cation on its IP are presented and discussed.
关键词： Transition metal oxides,Strong reducers,Mixed oxides,Superalkalis
更新于2025-09-23 15:23:52
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Fe doping effect of vanadium oxide films for enhanced switching electrochromic performances
摘要： In the present study, Fe-doped V2O5 films showing impressive electrochromic (EC) performance were developed using the sol-gel spin-coating method. To confirm the optimized Fe-doping effect on the V2O5 films for the EC performance, we adjusted the Fe atomic percentages to 0.0, 0.5, 1.0, and 1.5 at%, respectively. With the effect of Fe doping on the V2O5 films, the obtained films resulted in the formation of the oxygen vacancies. As the result, when the optimum Fe atomic percentage was 1.0 at%, the enhanced switching speeds (3.7 s for the bleaching speed and 2.0 s for the coloration speed) and enhanced coloration efficiency value (47.3 cm2/C) compared to the other films were implemented. This can be attributed to the improved electrical conductivity and Li+ diffusion coefficient that led to efficient generation of the EC reaction activity and narrowing the optical bandgap at the coloration state to increase transmittance modulation. Therefore, this unique film can be a promising EC material to improve the performance for the EC devices.
关键词： Films,Optical properties,Transition metal oxides,Electrical properties,Electrochromic performances
更新于2025-09-23 15:23:52
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Electrochemical properties of PEDOT: PSS /V2O5 hybrid fiber based supercapacitors
摘要： Binary conducting polymer (CP)/transition metal oxides (TMOs) fiber-based supercapacitors (FSCs) are considered to possess good electrochemical performance and cyclic stability compared with unitary ones since TMOs within FSCs can prevent the structure damage of CP during charge/discharge cycles to some extent. In this study, the CP/TMOs hybrid fibers are made by directly injecting the solution into capillary. Poly(3,4-ethylenedioxythiophene): polystyrene sulfonate /30 wt% vanadium pentoxide (PEDOT: PSS/30 wt% V2O5) fiber-based electrode has good electrochemical performance and cyclic stability (cycle retention: 94.02% after 4000 cycles at 0.1 mA/cm2). The energy density of the PEDOT: PSS/30 wt% V2O5 fiber in gel electrolyte is 1.37 μWh/cm2 at power density of 20 μW/cm2, which is much lower than the one in organic electrolyte (21.46 μWh/cm2 at power densities of 162.5 μW/cm2). Therefore, the method developed in this work induces good electrochemical performance for hybrid FSCs and promotes scalable fabrication of FSCs.
关键词： transition metal oxides,supercapacitor,Conducting polymers,electrochemical performance,hybrid fiber
更新于2025-09-23 15:23:52
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Electrochromism: a fascinating branch of electrochemistry
摘要： This lecture on electrochromism and electrochromic devices starts with a short introduction to the field. This is followed by an overview of the different classes of electrochromic materials, in which each class is illustrated by some typical examples. The third part deals with some basic parameters to assess electrochromic compounds and devices. After this, we discuss the different types of electrochromic devices or elements, again always illustrated by some examples. Manufacturing considerations and real-world practical application examples of electrochromics are the topics of the last two parts of this lecture.
关键词： Electrochromic devices,Transition metal oxides,Electrochromism,Conducting polymers,Smart windows
更新于2025-09-23 15:21:21
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Performance analysis of c-Si heterojunction solar cell with passivated transition metal oxides carrier-selective contacts
摘要： Transition metal oxides (TMOs) as passivating carrier-selective contact layers are investigated for silicon heterojunction solar cells. MoOx as hole-selective layer and TiOx as an electron-selective layer are explored in detail to design a high-efficiency silicon heterojunction solar cell without any specified surface passivation layer. The thickness and optical transparency of the MoOx hole-selective layer have been evaluated through optical simulation. The impact of TMOs’ work function and their passivation quality has been examined in detail to extract the maximum conversion efficiency from silicon heterojunction solar cells. To increase the optical absorption in c-Si, the micro–nanopillar structure has also been implemented. It has been found that the barrier height at the TMO/silicon heterocontact plays a significant role in the overall performance improvement of the solar cell. The optimized cell design without doping and separate passivating layer can achieve a power conversion efficiency of ~ 22%. Our findings open the potential pathways and opportunities to obtain simplified heterojunction solar cells at lower temperatures and without impurity doping.
关键词： Surface recombination velocity,Carrier-selective contact layers,Transition metal oxides,c-Si heterojunction solar cells
更新于2025-09-23 15:21:01
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Boosted Reactivity of Low-Cost Solar Cells over a CuO/Co <sub/>3</sub> O <sub/>4</sub> Interfacial Structure Integrated with Graphene Oxide
摘要： Developing cost-effective and environment-friendly counter electrodes (CEs) with high performance is central for the commercial application of dye-sensitized solar cells (DSSCs). In this work, the porous interfacial CuO/Co3O4@GO (CCO@GO) hybrid was fabricated by encapsulating the self-assembled CuO/Co3O4 nanosphere in graphene oxide (GO) and acted as a CE for the first time. Further measurements verified that the optimized CCO@GO hybrid not only provided a higher specific surface area (86.7 m2?g?1) with more exposed catalytic sites, but also significantly enhanced the power conversion efficiency (PCE = 8.34%) of DSSC, which was higher than that of the Co3O4-based CE (2.66%) and commercial Pt CE (7.85%). The results indicate that the interfacial CuO/Co3O4@GO hybrid synergistically accelerates the diffusion of I3?/I? redox couple and transmission of electrons, thus promoting the reaction kinetics. This work provides a remarkable way for exploring economical high-performance Pt-free CEs for DSSCs, as well as contributes to the further development for other energy-related fields.
关键词： DSSCs,interfacial structure,transition metal oxides,CuO/Co3O4@GO,counter electrode
更新于2025-09-23 15:19:57
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Interfacial engineering to boost photoresponse performance and stability of V2O5/n-Si heterojunction photodetectors
摘要： Transitional metal oxides (TMOs) have demonstrated as a promising alternative to doped layers in high-efficient crystalline silicon heterojunction solar cells. However, the unintentional oxidation causes serious carrier recombination at the interface, which accounts for the low photoelectric conversion efficiency and poor stability. Herein, a self-powered, broad-band, fast-response V2O5/n-Si heterojunction photodetectors (PDs) are fabricated by thermal evaporation of an ultrathin V2O5 thin films on nanoporous pyramid silicon structures. By interfacial engineering with structural optimization and surface methyl passivation, the photodetection performance and stability of V2O5/n-Si PDs can be significantly enhanced. The V2O5/n-Si heterojunction PDs demonstrate a high on/off ratio of 1.4×104, fast-response speed of 9.5 μs, high responsivity of 185 mA·W-1 (@940 nm) and high specific detectivity (1.34×1012 Jones). Based on the energy band alignment analysis, the excellent photoresponse performance is mainly attributed to the efficient carrier separation after surface passivation by methyl group. Additionally, the built-in electric field at the interface also accelerates the charge carrier separation. Our work would contribute to the fabrications of other TMOs-based heterojunctions, and give some enlightening insights into the understanding of carrier transportation in heterojunctions.
关键词： Carrier selective contact,Heterojunction photodetectors,Transition metal oxides,Interface engineering
更新于2025-09-16 10:30:52
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Current Localization and Redistribution as the Basis of Discontinuous Current Controlled Negative Differential Resistance in NbO <i> <sub/>x</sub></i>
摘要： Devices exploiting negative differential resistance (NDR) are of particular interest for analog computing applications, including oscillator-based neural networks. These devices typically exploit the continuous S-shaped current–voltage characteristic produced by materials with a strong temperature-dependent electrical conductivity, but recent studies have also highlighted the existence of a second, discontinuous (snap-back) characteristic that has the potential to provide additional functionality. The development of devices based on this characteristic is currently limited by uncertainty over the underlying physical mechanism, which remains the subject of active debate. In situ thermoreflectance imaging and a simple model are used to finally resolve this issue. Specifically, it is shown that the snap-back response is a direct consequence of current localization and redistribution within the oxide film, and that material and device dependencies are consistent with model predictions. These results conclusively demonstrate that the snap-back characteristic is a generic response of materials with a strong temperature-dependent conductivity and therefore has the same physical origin as the S-type characteristic. This is a significant outcome that resolves a long-standing controversy and provides a solid foundation for engineering functional devices with specific NDR characteristics.
关键词： brain-inspired computing,negative differential resistance,niobium oxide,thermoreflectance imaging,transition metal oxides
更新于2025-09-11 14:15:04
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Large tunability of strain in WO3 single-crystal microresonators controlled by exposure to H2 gas
摘要： Strain engineering is one of the most effective approaches to manipulate the physical state of materials, control their electronic properties, and enable crucial functionalities. Because of their rich phase diagrams arising from competing ground states, quantum materials are an ideal playground for on-demand material control, and can be used to develop emergent technologies, such as adaptive electronics or neuromorphic computing. It was recently suggested that complex oxides could bring unprecedented functionalities to the field of nanomechanics, but the possibility of precisely controlling the stress state of materials is so far lacking. Here we demonstrate the wide and reversible manipulation of the stress state of single-crystal WO3 by strain engineering controlled by catalytic hydrogenation. Progressive incorporation of hydrogen in freestanding ultra-thin structures determines large variations of their mechanical resonance frequencies and induces static deformation. Our results demonstrate hydrogen doping as a new paradigm to reversibly manipulate the mechanical properties of nanodevices based on materials control.
关键词： Tungsten Trioxide,Hydrogen Doping,MicroElectroMechanical Systems,WO3,Transition Metal Oxides,Oxide MEMS,Strain Engineering,Chemical Strain
更新于2025-09-11 14:15:04
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Nanoscale oxygen ion dynamics in SrFeO <sub/>2.5+δ</sub> epitaxial thin films
摘要： A variety of functional properties in transition metal oxides are often underpinned by oxygen vacancies. While the oxygen vacancy concentration and arrangements are well-known to have strong influence on the physical properties of oxides, the oxygen dynamics in oxides—including oxygen ion incorporation and movements during redox reactions—remain elusive. Performing conductive AFM studies of epitaxial thin films of oxygen-deficient SrFeO2.5 treated by air-annealing at various temperatures, we observe oxidation-induced enhancement of local electronic conduction on the higher terraces near the outer step edges at which oxygen ions are preferably incorporated and diffuse into the films. We also show that the local conduction can be reversibly controlled by electric-field-induced redox reactions at room temperature. These results highlight the importance of the nanoscale oxygen dynamics in redox reactions in SrFeO2.5 films.
关键词： SrFeO2.5,transition metal oxides,redox reactions,conductive AFM,oxygen vacancies
更新于2025-09-09 09:28:46