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oe1(光电查) - 科学论文

26 条数据
?? 中文(中国)
  • Integration of organic/inorganic nanostructured materials in a hybrid nanogenerator enables efficacious energy harvesting via mutual performance enhancement

    摘要: Recent reports demonstrate that hybrid energy harvesting devices can efficiently convert ubiquitously available but mostly unexploited ambient energies (e.g., mechanical, chemical, thermal, solar) into usable power that can potentially support a new generation of self-powered electronic systems. In this paper, we present a hybrid organic/inorganic nanogenerator on shim substrates, which integrates both piezoelectric and triboelectric components based on inorganic p-n junction ZnO nanostructures and nanostructured organic polytetrafluoroethylene (PTFE) film, respectively. In this design, individual components can be operated independently or concurrently. Moreover, when operated concurrently, component performance is mutually enhanced, enabling more efficient conversion of mechanical energy into electrical energy in a single press-and-release cycle. When triggered with 25 Hz frequency and 1G acceleration of external force, the piezoelectric nanogenerator (PENG) component generates a peak-to-peak output voltage of 34.8V, which is ~3 times higher than its output when it acts alone. Similarly, the triboelectric nanogenerator (TENG) component generates a peak-to-peak output voltage of 356V under the same conditions, which is higher than its initial output of 280V when acting alone. The nanogenerator unit produces an average peak output voltage of 186 V, current density of 10.02 μA/cm2, and average peak power density of 1.864 mW/cm2 when operated in the hybrid configuration. The device can even produce an average peak-to-peak voltage of ~160V from normal hand movement when placed under a wristband fitness tracker, and ~580V from human walking when placed within the walker’s shoe. The device has been demonstrated to charge commercial capacitors up to a few volts within several seconds.

    关键词: nanoplates,energy harvesting,hybrid nanogenerators,nanowires,piezoelectricity,triboelectricity

    更新于2025-09-23 15:23:52

  • One-Step Solvothermal Formation of Pt Nanoparticles Decorated Pt <sup>2+</sup> -Doped α-Fe <sub/>2</sub> O <sub/>3</sub> Nanoplates with Enhanced Photocatalytic O <sub/>2</sub> Evolution

    摘要: The photooxidation of water into O2 has been identified as the barrier of water-splitting, and light-driven water oxidation catalysts have been intensively explored to develop highly active water splitting materials. Despite the fascinating advantages for photocatalytic water oxidation, such as abundance in nature, inexpensiveness, low toxicity, thermo/photo-stability, and suitable electronic band structures, hematite α-Fe2O3 is a poor photocatalyst for water oxidation due to its short exciton lifetime and hole diffusion length, weak carrier mobility and shallow sunlight penetration depth. In this work, we have synthesized Pt nanoparticles decorated Pt2+-doped α-Fe2O3 nanoplates (Pt/Pt-Fe2O3 NPs) by a one-step solvothermal route, which exhibit the enhanced photoactivity and photostablity for water oxidation. The introduction of the Pt into the α-Fe2O3 by the means of elemental doping and nanoparticle decoration accounts for the enhanced performance. The doping of Pt2+ into α-Fe2O3 improves the isolation efficiency of the photo-induced carriers which remarkably increases the lifespan of hole carriers, and the adherence of metal Pt nanoparticles to the surface of α-Fe2O3 leads to formation of schottky barriers at the interface which effectively impedes the combination of photo-generated electrons and holes.

    关键词: photocatalytic O2 evolution,Pt nanoparticles decoration,Pt2+ doping,schottky barrier,α-Fe2O3 nanoplates

    更新于2025-09-23 15:23:52

  • Effect of defects in TiO2 nanoplates with exposed {001} facets on the gas sensing properties

    摘要: The exposed crystal facet of TiO2 is a crucial factor influencing the gas sensing properties. TiO2 with high-energy {001} crystal facets that have higher surface energy and reactivity is expected to exhibit excellent gas-sensing properties. In this paper, TiO2 nanoplates with defective {001} facets were synthesized by chemical etching via one-step hydrothermal method. We carefully explored the gas-sensing performance of TiO2 nanoplates with defective and complete {001} facets towards acetone. The results show that the sensing response of TiO2 nanoplates with complete {001} facets is 70% higher than that of defective TiO2 nanoplates, which proves that the {001} facets plays a vital role in improving the gas sensing performance of TiO2. It is speculated that the poor gas sensitivity of defective TiO2 can be contributed to fewer adsorption sites and blocked electron transfer. This work presents a more direct evidence for explaining the important role of the complete {001} crystal facets in high sensitivity of TiO2 and also provides a new insight for preparing high sensitivity sensing materials.

    关键词: TiO2 nanoplates,Defective,Acetone,{001} facets,Gas sensing

    更新于2025-09-23 15:22:29

  • Stress field around graphene nanoplates coated carbon fiber strand reinforced in polymer matrix

    摘要: Photoelasticity method was used to map the stress field around the graphene nanoplates (GnPs) coated carbon fiber strand reinforced in a polymer matrix. Carbon fiber strand (0.4 mm diameter, containing 40 carbon fibers) was considered. The composite was subjected to diametrical compression. The models were loaded under partial edge compression having 0o, 45o and 90o orientation of fiber strand with respect to loading axis. Typical isochromatic fringe patterns were observed using circular polariscope which indicated that GnPs coated carbon fiber strand inferred the direction of isochromatics. Stress concentration near the fiber region was observed. The isochromatics were slightly bent towards fiber strand which showed the strong adhesion of fiber strand with the polymer matrix. The fringe order calculated from orthotropic Mohr’s circle relevance of fringe order was different from isotropic fringe order. The isochromatic fringe pattern for composite with 0o fiber orientation was almost similar to pure epoxy. This showed that the compressive behavior of fabricated 0o oriented GnPs coated carbon fiber strand composite was almost similar to pure epoxy. The calculated values of stresses at the center of the disc showed that composite with 0o orientation of fiber strand was most effective in stress sharing. The calculation of stress fringe value for 45o orientation of fiber strand showed that aligning fiber strand at 45o doesn’t represent the case of pure shear in fiber reinforced composites. However, the deviation from pure shear was very less

    关键词: Isochromatic fringes,Compressive load.,Photoelasticity,Epoxy resin,Graphene nanoplates

    更新于2025-09-23 15:22:29

  • A novel growth control of nanoplates WO3 photoanodes with dual oxygen and tungsten vacancies for efficient photoelectrochemical water splitting performance

    摘要: Recently, there has been attractive attention over the defect-engineering where the optimum extent of oxygen deficiency has been considered as an effective route towards enhancing the solar-driven water oxidation photocurrent. In this study, a nanoplate-like tungsten oxide with dual oxygen and tungsten vacancies (WO3-x) was successfully fabricated on tungsten foil by acid-mediated hydrothermal treatment to highly improve the photoelectrochemical (PEC) performance of WO3-x photoanode. Thermal annealing at 550 °C in air led to an oxygen deficient surface with a sub-stoichiometric by phase transformation from orthorhombic WO3·.nH2O to γ-monoclinic. However, the optimum number of oxygen vacancies in WO3-x fabricated at 2 h (W-2 h) with compact, porous and uniform nanoplate film that provide a large surface area for efficient charge collecting capability, caused an enhanced photocurrent density of 4.12 mA/cm2 (41.2 mA/W) at 1.6 V vs. Ag/AgCl, as compared to W-3 h (2.59 mA/cm2, or 25.9 mA/W) and W-30 min (1.79 mA/cm2 or 17.9 mA/W). Finally, local variations in dual oxygen and tungsten vacancies and in the electronic band structure of a WO3-x thin film was analyzed with ultraviolet photoelectron spectroscopy (UPS) and UV–visible diffuse reflectance spectroscopy (UV-DRS).

    关键词: Photoelectrocatalytic,Water splitting,Growth control,Oxygen and tungsten vacancies,Nanoplates,WO3-X

    更新于2025-09-23 15:21:21

  • Ultrasound assisted deposition of highly stable self-assembled Bi2MoO6 nanoplates with selective crystal facet engineering as photoanode

    摘要: The use of crystal facets of photocatalysts is well known as a promising strategy for the design of new photocatalysts with interesting physicochemical features for energy production applications. In this work, Bi2MoO6 thin films were synthesized by two methods, electrodeposition and sonoelectrodeposition. Preferential growth orientation depended on synthesis method. Results suggested that sonoelectrodeposition led to dominate the crystal facet {1 0 0} growth with self-assembled nanoplate morphologies while growth orientation in the {0 1 0} facet was dominant in electrodeposition in the absence of ultrasonic waves. As a highlight result, the {1 0 0} facet shows a smaller band gap, higher photocatalytic water splitting than the {0 1 0} facet. Efficient separation of charge pairs and long life time of photogenerated electrons was observed to be intrinsic features of the {1 0 0} facets. The higher charge transfer was confirmed by a higher photocurrent from linear sweep voltammetry and a smaller Nyquist radius arc. Ultrasound plays a key role in growth orientation and led to a production of homogeneous films with nanoplates which self-assembled together to form a flower-like structure. While in the absence of ultrasound the film has coral-like structure. Highly stable sonoelectrodeposited films exhibited incident photon-to-electron conversion efficiency (IPCE) of 22.4% at the specific wavelength of 500 nm. The sonoelectrodeposition method could act as a promising method for forming new films with specific crystal facet selection and developing as highly efficient photoanodes for PEC water splitting.

    关键词: Crystal facet engineering,Coral-like,Water splitting,Bismuth molybdate,Self-assembled nanoplates,Sonoelectrodeposition

    更新于2025-09-23 15:21:01

  • Luminescence relaxation dynamics for planar and rolled-up CdSe nanocrystals in a photonic-crystal matrix

    摘要: Samples of inverted photonic-crystal films, containing planar and rolled-up (in the form of scrolls) CdSe nanocrystals, are studied. The transmission spectra of these structures are recorded. These spectra (along with the change in colour) confirm the incorporation of nanocrystals into the films. The photoluminescence decay dynamics is investigated. It is shown that the photonic-crystal matrix affects significantly the luminescence kinetics of nanostructures. The differences in the decay curves measured for nanocrystals in a photonic-crystal matrix and for their ensemble on a glass substrate are explained by the influence of the photonic-crystal stop band and the orientational effect of crystalline matrix, which orients anisotropic nanocrystals and prevents them from aggregation. The results obtained may be important for potential applications in optoelectronic devices.

    关键词: nanoscrolls,luminescence kinetics,photonic crystal,nanoplates,CdSe

    更新于2025-09-23 15:21:01

  • Construction of Long Narrow Gaps in Ag Nanoplates

    摘要: Hexagonal Ag nanoplates with long and ultra-narrow gaps (about 90 nm in length, 2 nm in width) are synthesized via seed-mediated growth method. By growing around the polymer shell on the seed, the Ag domain cannot merge at the meet-up point, leaving a long narrow gap in the resulting plate. These gapped nanoplates exhibit high sensitivity in SERS detection, with limitation of 10-9 M for 2-naphthalenethiol.

    关键词: SERS,ultra-narrow gaps,Ag nanoplates,seed-mediated growth

    更新于2025-09-23 15:21:01

  • {0 0 1}-Facet-Exposed Ag <sub/>4</sub> V <sub/>2</sub> O <sub/>7</sub> Nanoplates: Additive-Free Hydrothermal Synthesis and Enhanced Photocatalytic Activity

    摘要: The synthesis of silver pyrovanadate, Ag4V2O7, nanoplates with exposed {0 0 1}-facets by a facile, additive-free hydrothermal method was described in this paper. The photocatalytic activity of rhodamine B over Ag4V2O7 samples under solar light irradiation was also evaluated. By using an equimolar mixture of NH4VO3 and AgNO3 with the presence of a suitable amount of ammonia, Ag4V2O7 nanoplates were obtained readily and purely at temperatures from 100 to 140°C for 4 h. The c-axis orientation growth of Ag4V2O7 nanoplates occurred and increased monotonously with temperatures in the range of over 100 up to 140°C. Further increase in hydrothermal temperature up to 220°C, the Ag4V2O7 phase no longer existed and the β-AgVO3 phase was formed instead. The photocatalytic activity of the optimized Ag4V2O7 sample comprising {0 0 1}-facet-exposed nanoplates with the highest degree of orientation was significantly higher than that of the random-oriented sample. The effects of using ammonia as a complexing agent on the structure, microstructure, texture, exposed facet, and photocatalytic activity of Ag4V2O7 samples were also investigated for the first time.

    关键词: photocatalytic activity,hydrothermal synthesis,Ag4V2O7,rhodamine B,nanoplates,solar light irradiation

    更新于2025-09-23 15:21:01

  • Post-annealed graphite carbon nitride nanoplates obtained by sugar-assisted exfoliation with improved visible-light photocatalytic performance

    摘要: Two-dimensional (2D) graphitic carbon nitride (g-C3N4) nanoplates (CNNP) have become a hot research topic in photocatalysis due to their small thickness and large specific surface area that favors charge transport and catalytic surface reactions. However, the wide application of 2D g-C3N4 nanoplates prepared by ordinary methods suffers from increased band gaps with a poor solar harvesting capability caused by the strong quantum confinement effect and reduced conjugation distance. In this paper, a facile approach of exfoliation and the following fast thermal treatment of the bulk g-C3N4 is proposed to obtain a porous few-layered g-C3N4 with nitrogen defects. Due to the preferable crystal, textural, optical and electronic structures, the as-obtained porous CNNP demonstrated a significantly improved photocatalytic activity towards water splitting than the bulk g-C3N4 and even the 3 nm-thick CNNP obtained by sugar-assisted exfoliation of the bulk g-C3N4. The difference in the enhancement factors between the H2O splitting and organic decomposition has revealed the effect of N defects. This study offers insightful outlooks on the scalable fabrication of a porous few-layered structure with a promoted photocatalytic performance.

    关键词: Photocatalytic activity,g-C3N4 nanoplates,Co-grinding,Thermal treatment,Sugar

    更新于2025-09-23 15:19:57