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Nonvolatile Resistive Switching Memory Device Employing CdSe/CdS Core/Shell Quantum Dots as an Electrode Modification Layer
摘要： Accompanied with great advantages in various fields of performance, memristors show huge potential in the next generation of mainstream storage devices. However, their random distribution of resistance switching voltage has always been one of the problems in applications. In this present work, a nonvolatile resistive switching memory device was proposed, which employed CdSe/CdS core/shell quantum dots (QDs) assembled as an electrode modification layer with the device configuration of Pt/CdSe-CdS QDs/TaOx/Ta. The device possesses multiple excellent resistance switching characteristics such as lower and more consistent set/reset threshold voltage and better endurance performance, which is considered as the effect of the electrode modification layer based CdSe/CdS core/shell QDs. A model with uneven QDs/Pt electrode interface was put forward to explain the different resistance switching behaviors, which may be beneficial to the development of existing research about memristors based on metal oxides and quantum dots.
关键词： Migration,Oxygen vacancy,Schottky interface,CdSe/CdS core/shell quantum dots,resistive switching
更新于2025-09-19 17:13:59
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Modulation of Plasticity of All-metal Oxide Synaptic Transistor via Laser Irradiation
摘要： Artificial intelligence device mimicking human brains is the foundation for building future artificially neural networks. A key step to mimic biological neural systems is the modulation of synaptic weight, which is mainly achieved by various engineering approaches with materials design or modification of device structure. Here, we realized the modulation of synaptic weight of Ta2O5/ITO based all-metal oxide synaptic transistor via laser irradiation. Prior to the deposition of active layer and electrodes, fs-laser was induced to irradiate on the surface of insulator layer. The typical synaptic characteristics such as excitatory post synaptic current (EPSC), paired pulse facilitation (PPF) and long term potentiation (LTP) were successfully simulated under different laser intensities and scanning rates. Particularly, we demonstrated for the first time that laser irradiation could control the amount of oxygen vacancies in the Ta2O5 thin film, leading to the precise modulation of synaptic weight. Our research provides an instantaneous(<1s), convenient and low-temperature approach to improve synaptic behaviors, which would be promising for neuromorphic computing hardware design.
关键词： synaptic transistor,laser irradiation,oxygen vacancy,Ta2O5
更新于2025-09-19 17:13:59
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Amorphous ZnO/PbS quantum dots heterojunction for efficient responsivity broadband photodetectors
摘要： The integration of lead sulfide quantum dots (QDs) with high conductivity material that is compatible with a scalable fabrication is an important route for the applications of QDs based photodetectors. Herein, we firstly developed a broadband photodetector by combining amorphous ZnO and PbS QDs forming a heterojunction structure. The photodetector showed detectivities up to 7.9x1012 jones and 4.1x1011 jones under 640 nm and 1310 nm illumination, respectively. The role of oxygen background pressure on the electronic structure of ZnO films grown by pulsed laser deposition was systematically studied, and it was found to play an important role on the conductivity, associated to the variation of oxygen vacancy concentration. By increasing the oxygen vacancy concentration, the electron mobility of amorphous ZnO layers dramatically increased and work function decreased, which were beneficial for the photocurrent enhancement of ZnO/PbS QDs photodetectors. Our results provide a simple and highly scalable approach to develop broadband photodetectors with high performance.
关键词： oxygen vacancy,amorphous ZnO,broadband photodetector,mobility,heterojunction
更新于2025-09-16 10:30:52
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Interfacial Lattice‐Strain‐Driven Generation of Oxygen Vacancies in an Aerobic‐Annealed TiO <sub/>2</sub> (B) Electrode
摘要： Oxygen vacancies play crucial roles in defining physical and chemical properties of materials to enhance the performances in electronics, solar cells, catalysis, sensors, and energy conversion and storage. Conventional approaches to incorporate oxygen defects mainly rely on reducing the oxygen partial pressure for the removal of product to change the equilibrium position. However, directly affecting reactants to shift the reaction toward generating oxygen vacancies is lacking and to fill this blank in synthetic methodology is very challenging. Here, a strategy is demonstrated to create oxygen vacancies through making the reaction energetically more favorable via applying interfacial strain on reactants by coating, using TiO2(B) as a model system. Geometrical phase analysis and density functional theory simulations verify that the formation energy of oxygen vacancies is largely decreased under external strain. Benefiting from these, the obtained oxygen-deficient TiO2(B) exhibits impressively high level of capacitive charge storage, e.g., ≈53% at 0.5 mV s?1, far surpassing the ≈31% of the unmodified counterpart. Meanwhile, the modified electrode shows significantly enhanced rate capability delivering a capacity of 112 mAh g?1 at 20 C (≈6.7 A g?1), ≈30% higher than air-annealed TiO2 and comparable to vacuum-calcined TiO2. This work heralds a new paradigm of mechanical manipulation of materials through interfacial control for rational defect engineering.
关键词： aerobic-annealing,oxygen vacancy,pseudocapacitive charge storage,lithium-ion batteries,interfacial lattice strain
更新于2025-09-12 10:27:22
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Oxygen non-stoichiometry in TiO2 and ZnO nano rods: Effect on the photovoltaic properties of dye and Sb2S3 sensitized solar cells
摘要： Rutile TiO2 (TiO2-NR) and ZnO (ZnO-NR) in nanorod microstructural forms are synthesized by hydrothermal route. The oxides are grown directly on fluorine doped SnO2 coated glass, and annealed in air (AA) and hydrogen (HA) atmosphere for 3 h at 450 °C. A detailed structural, optical, and microstructural study confirms the phase formation in the AA and stability in HA samples. EPR signal with g-values of ~1.99 and ~1.95 from TiO2-NR and ZnO-NR photoanodes respectively confirms the presence of oxygen vacancy (OV) related defects. The EPR signals are stronger in TiO2-NR-HA compared to TiO2-NR-AA and is absent in ZnO-NR-AA suggesting increased defect concentration on hydrogenation. Further this leads to two order increase in photoconductivity for hydrogenated TiO2-NR-HA and ZnO-NR-HA photoanodes when measured under 1 Sun illumination compared to AA photoanodes. Photovoltaic power conversion efficiency for both dye and Sb2S3 sensitized solar cells are found to increase by 2 to 3 times in hydrogenated ZnO-NR. In contrast, TiO2-NR show two-fold decrease in efficiency on hydrogenation. The efficiency change is consistent with the change in interface impedance, which increases for dye or Sb2S3 sensitized TiO2-NR-HA photoanode, whereas, decreases for sensitized ZnO-NR-HA photoanode. These studies show that despite of one to two to three order increase in photoconductivity, the sensitizer/photoanode interface impedance play a significant role in deciding the efficiency.
关键词： Oxygen vacancy,Nanorod,Photoanode,Efficiency,ZnO,Solar cell,TiO2
更新于2025-09-12 10:27:22
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Effect of deep UV laser treatment on silicon-doped Tin oxide thin film
摘要： In this paper, the effect of deep ultraviolet (UV) laser on physical and electrical properties of amorphous Silicon‐doped tin oxide (amorphous Si‐Sn‐O, a‐STO) thin films were studied. Surface morphology, thickness, crystallinity, and optical band gap of a‐STO thin films treated by laser were investigated. Results showed that the decrease of thickness and surface roughness of a‐STO thin films after deep UV laser treatment, and the films maintained an amorphous structure, which implied that the quality of a‐STO thin films were improved. The peak position of oxygen vacancy binding energy became lower; this is caused by an increase in oxygen vacancies resulting in a decrease in coordination number. And the oxygen vacancy content of the a‐STO thin films was increased after deep UV laser treatment. In addition, the optical band gap of a‐STO films was broaden after the deep UV laser treatment. It exploits a new application of deep UV laser in oxide semiconductor.
关键词： oxygen vacancy,amorphous STO thin film,optical band gap,deep ultraviolet laser
更新于2025-09-12 10:27:22
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SnO2 surface defects tuned by (NH4)2S for high-efficiency perovskite solar cells
摘要： Tin oxide (SnO2) is widely adopted as an electron transport layer (ETL) in perovskite solar cells (PSCs). However, the oxygen vacancies of the SnO2 not only are the trap states of the nonradiative recombination of photo-generated carriers, but also build the potential barrier of carrier transport. To solve this issue, ammonium sulfide [(NH4)2S] is introduced to the SnO2 precursor for passivating the surface defects by terminating the Sn dangling bonds (S–Sn bonds). After reducing the surface traps, the electron mobility and conductivity of SnO2 film are enhanced significantly while the carrier recombination is decreased. Additionally, the energy level of S-SnO2 is also slightly modified. Therefore, this sulfide-passivated mothed remarkably improves the electron collection efficiency of the ETL. Furthermore, the linkage of Sn–S–Pb anchors the perovskite crystals at the perovskite/SnO2 interface, which increases the electron extraction efficiency and the stability of PSC. Based on this S-SnO2 ETL, the power conversion efficiency of the PSC is greatly promoted from 18.67% to 20.03%, compared with the reference one. In this study, it is proven that the surface defect passivation of SnO2 is an efficient and simple method to improve the photovoltaic performance, as a promising ETL for high-efficiency device.
关键词： Oxygen vacancy,Carrier transport dynamic,SnO2 electron transport layer,Surface passivation,Perovskite solar cells
更新于2025-09-12 10:27:22
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Carbon supported oxygen vacancy-rich Co3O4 for robust photocatalytic H2O2 production via coupled water oxidation and oxygen reduction reaction
摘要： Photocatalytic H2O2 production is a promising strategy to alleviate energy crisis since H2O2 is an important liquidus chemical and fuel. However, the following problems severely restrict the development of this technique: (1) low selectivity; (2) low stability (normally less than 5 short-time cycles); (3) fast charge recombination; (4) assistance of hole scavengers and (5) demand of O2 saturation. Herein, carbon supported oxygen vacancy-rich Co3O4 nanoplate (C-ovCo) is reported as an efficient photocatalyst for scavenger-free H2O2 production by coupled 2e– water oxidation (WOR) and 2e? oxygen reduction reaction (ORR) with low energy barrier of 1.1 eV. In this system, the oxygen vacancies can reduce the band gap, enhance the donor density, improve the charge separation and migration and work as WOR sites, while the carbon support accepts electrons and works as ORR sites. The photocatalysts exhibit an optimal H2O2 production rate of 3.78 mmol h–1 g–1 under visible light (λ ≥ 420 nm), an apparent quantum efficiency (AQE) of 16.7% at 420 nm, and a solar-to-chemical efficiency (SCC) of 0.4%. Moreover, the stability of over 720 h (30 long-time cycles) is also superior to the state-of-the-art photocatalytic systems.
关键词： Carbon supported oxygen vacancy-rich Co3O4,Coupled reaction,Photocatalytic H2O2 production,Oxygen reduction reaction,Water oxidation reaction
更新于2025-09-11 14:15:04
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Controlled synthesis of nanocrystalline Nb:SrTiO <sub/>3</sub> electron transport layers for robust interfaces and stable high photovoltaic energy conversion efficiency in perovskite halide solar cells
摘要： Perovskite halides are of great attraction as efficient light absorption materials for solid-state solar cells, but the stability and photovoltaic energy conversion efficiency of perovskite solar cells (PSCs) are still limited by the interface structures and defects between their light-absorbing perovskite halides and electron transport layers (ETLs). Here, we report the ultraviolet (UV) light-induced degradation mechanism at the interfaces between perovskite halide and conventional TiO2 ETL materials, and provide a solution to overcome this drawback. UV-induced degradation is shown to be attributed to the formation of oxygen vacancies formed at the perovskite halide-ETL interface under UV light illumination, where the oxygen atoms released at the interface accelerate the decomposition of perovskite halide by inducing chemical reactions. Meanwhile, nanocrystalline SrTiO3 (STO) ETLs are revealed to be tunable in enabling high performance in PSCs under UV light illumination. Indeed, tuning the electronic structure of STO ETLs by Nb doping, in combination with the controllable removal of SrO phases segregated on the Nb-doped STO ETL surfaces, is exhibited to enable robust interface stability and stable high photovoltaic energy conversion efficiency for PSCs. Furthermore, we demonstrate that STO-based PSCs have no hysteresis due to low defect concentrations at the perovskite halide-STO ETL interfaces.
关键词： oxygen vacancy formation,electron transfer layer,perovskite oxides,photo stability,Perovskite solar cells
更新于2025-09-11 14:15:04
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Shape-controlled synthesis of golf-like, star-like, urchin-like and flower-like SrTiO3 for highly efficient photocatalytic degradation and H2 production
摘要： As a typical perovskite-type metal oxide, SrTiO3 has emerged as a prospective candidate for many fields. However, the synthesis of SrTiO3 with controlled morphology, high surface area, and enhanced photocatalytic activity are still lacking. Herein, a series of porous SrTiO3 with well-controlled morphologies including assembled nanoparticles (ANPs), golf-like particles (GLPs), star-like microspheres (SLMs), urchin-like microspheres (ULMs), and flower-like microspheres (FLMs) were successfully prepared via an ethylene glycol-water mixed solvothermal route. The ratio of VEG/VH2O play an important role in the shape-evolution during the solvothermal reaction. A comparative study of photocatalytic H2 production and photodegradation was performed, and a possible photocatalysis mechanism of SrTiO3 has been proposed. Significantly, the ULMs and FLMs photocatalysts of SrTiO3 with optimized low Pt loading amount (0.075wt.%) exhibited outstanding H2 production rates (8.21 and 7.29 mmol·g-1·h-1) due to its unique structure of high-surface area and defect-rich surface. The facile and shape-controlled synthesis of varied SrTiO3 structures is believed to be useful for the design and application of perovskite.
关键词： Mesoporous SrTiO3,Oxygen vacancy,Photocatalysis,Controlled-synthesis,Morphology evolution
更新于2025-09-11 14:15:04