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Mo-doped Zn, Co Zeolitic-Imidazolate Framework-derived Co9S8 Quantum Dots and MoS2 Embedded in Three-Dimensional Nitrogen Doped Carbon Nano???ake Arrays as an Efficient Trifunctional Electrocatalysts for ORR, OER and HER
摘要： Herein, we first propose a facile strategy to synthesize Co9S8 and MoS2 nanocrystals embedded in porous carbon nanoflake arrays supported on carbon nanofibers (Co9S8-MoS2/N-CNAs@CNFs) by the pyrolysis of Mo-doped Zn, Co zeolitic-imidazolate framework grown on carbon nanofibers and subsequent sulfuration. The electrocatalyst shows high and stable electrocatalytic performance, with half-wave potential of 0.82 V for ORR and overpotential at 10 mA cm-2 for OER (0.34 V) and HER (0.163 V), which outperform the metal-organic frameworks-derived transition metal sulfide catalysts reported so far. Furthermore, the Co9S8-MoS2@N-CNAs@CNFs are employed as an air cathode in a liquid-state and all-solid-state zinc-air battery, presenting high power density of 222 mW cm-2 and 96 mW cm-2, respectively. Such excellent catalytic activities are mainly owing to the unique three-dimensional structure and chemical compositions, optimal electronic conductivity, adequate surface area and the abundance of active sites. Thus, this work provides an important method for designing other metal-organic frameworks derived three-dimensional structural sulfide quantum dot multifunctional electrocatalyst for wider application in highly efficient catalysis and energy storage.
关键词： zeolitic-imidazolate framework,Co9S8 quantum dots,MoS2,nitrogen-doped carbon nanoflakes arrays,Zn-air battery,trifunctional electrocatalysts
更新于2025-09-23 15:19:57
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - All-Fiber 2.07 μm Distributed Feedback Laser Based on π-Phase-Shifted FBG Inscribed in Heavily Doped Holmium Fiber by Femtosecond Laser Pulses
摘要： Distributed-feedback (DFB) fiber laser is a versatile source of low-noise single-frequency radiation that finds applications in spectroscopy, optical communications and sensing devices. Depending on the active medium, different lasing wavelengths can be obtained: 1.03–1.12 μm for Yb, 1.53–1.62 μm for Er, and 1.73–1.93 μm for Tm-doped fibers. Special fiber Bragg grating (FBG) with a length of 20–70 mm and phase shift in the structure, directly written in an active medium, serves as distributed feedback cavity of this type of laser. Commonly, special UV photosensitive fibers and phase masks inscription technique are used for an FBG fabrication. Alternative femtosecond (fs) point-by-point technique [1] has a number of advantages as compared to UV-based ones: 1) wide variety of active fibers can serve as a host material for an FBG, thanks to the nonlinear mechanism of fs pulses absorption, 2) FBG period can be easily tuned by controlling fs pulses frequency and velocity of fiber translation during the inscription process, 3) each fiber grating “pitch” can be written independently, which means that phase shift with an exact value and position along FBG can be introduced. Despite the number of publications dealing with holmium fiber lasers [2], there no publications devoted to DFB ones. At the same time, such type of laser sources has a great potential as a master oscillator in all-fiber coherent beam combination systems [3]. We report on the creation of holmium-doped DFB fiber laser with a wavelength of 2.07 μm operating in single-frequency regime (Fig. 1a). The laser is based on custom-made single-mode holmium-doped fiber having absorption coefficient about 43 dB/m at 1.125 μm, which is the wavelength of pump Yb fiber laser. 42-mm π-phase-shifted FBG was directly inscribed in the active fiber by femtosecond IR laser pulses and served as distributed feedback cavity of the laser. Lasing threshold was reached at 350 mW pump power, and output power exceeded 36 mW at pump power of 4.8 W (Fig. 1b). Single-polarization mode operation was observed with linewidth of ~10 kHz. Additionally to the room-temperature operation regime we will present and discuss the laser operation regimes at cryogenic temperature (77 K), as well as high-temperature (>400 K). To the best of our knowledge, it is the first realization of all-fiber DFB laser based on holmium active medium.
关键词： femtosecond laser pulses,holmium-doped fiber,single-frequency radiation,Distributed-feedback fiber laser,π-phase-shifted FBG
更新于2025-09-23 15:19:57
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Ytterbium-doped fibre femtosecond laser offers robust operation with deep and precise microsurgery of C. elegans neurons
摘要： Laser microsurgery is a powerful tool for neurobiology, used to ablate cells and sever neurites in-vivo. We compare a relatively new laser source to two well-established designs. Rare-earth-doped mode-locked fibre lasers that produce high power pulses recently gained popularity for industrial uses. Such systems are manufactured to high standards of robustness and low maintenance requirements typical of solid-state lasers. We demonstrate that an Ytterbium-doped fibre femtosecond laser is comparable in precision to a Ti:Sapphire femtosecond laser (1–2 micrometres), but with added operational reliability. Due to the lower pulse energy required to ablate, it is more precise than a solid-state nanosecond laser. Due to reduced scattering of near infrared light, it can lesion deeper (more than 100 micrometres) in tissue. These advantages are not specific to the model system ablated for our demonstration, namely neurites in the nematode C. elegans, but are applicable to other systems and transparent tissue where a precise micron-resolution dissection is required.
关键词： Ytterbium-doped fibre femtosecond laser,Laser microsurgery,neuronal regeneration,Ti:Sapphire femtosecond laser,solid-state nanosecond laser,C. elegans
更新于2025-09-23 15:19:57
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Al-doped zinc stannate films for photovoltaic applications
摘要： Al-doped zinc stannate (Zn2SnO4 : Al or Zn-Sn-O : Al or AZTO) has attracted considerable attention as a next-generation transparent conducting oxide (TCO) owing to its properties. In this study, AZTO films were deposited by co-sputtering Al-doped zinc oxide (AZO) and SnO2 targets at room temperature. The as-deposited AZTO films were confirmed to be satisfactorily adherent with good uniformity. These films had an average transmittance of over 80%, energy band gap of >3.5 eV, and relatively low electrical resistivity of 1.29×10?1 Ω cm. The composition ratio of Zn/Sn at 140 W of SnO2 power was approximately 2, indicating the formation of AZTO film with stoichiometric composition of Zn2SnO4 : Al at this power. Further, the Cu(InGa)Se2 (CIGS) device fabricated with AZTO (140 W) as a TCO exhibited an efficiency of 0.73%, with a VOC of 0.51 V, JSC of 3.76 mA/cm2, and FF of 38.4%. Furthermore, the conversion efficiency of CIGS cell was enhanced to 2.82% by employing the AZTO film deposited at the elevated temperature of 350 oC.
关键词： Al-doped Zinc Stannate,Thin Films,Cu(InGa)Se2,Transparent Conducting Oxides
更新于2025-09-23 15:19:57
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Sandwich magnetically imprinted immunosensor for electrochemiluminescence ultrasensing diethylstilbestrol based on enhanced luminescence of Ru@SiO2 by CdTe@ZnS quantum dots
摘要： A molecularly imprinted magnetic sensor with electroluminescent tags (MIP-ECL sensor) was developed for ultrasensing diethylstilbestrol (DES). A strategy is exploited to enhance ECL emission of the [Ru(bpy)3]2 +-tripropyl amine (TPrA) system by CdTe@ZnS quantum-dots (QDs) through energy transfer. Magnetically molecularly imprinted nanoparticles (MMIPs NPs) based on Fe3O4@SiO2 carriers are artificial, easily reproducible, and could replace easily inactivated first antibodies for capturing more DES molecules. Functionalized bio-conjugates of single antibody-CdTe@ZnS (Ab-CdTe@ZnS) are for the first time loaded on signal labels of Ru(bpy)3 2 +-doped silica nanocomposites (Ru@SiO2) for signal amplification. The final bio-conjugated signal probes are denoted as Ab-DES/CdTe@ZnS-Ru@SiO2. MMIPs beads that have captured antigens are bio-conjugated with antibody-labeled luminescent probes by specific immunoreactive reaction, and then the luminescent immunocomplex generates ECL signal on the magnetic electrode. The logarithm of ECL intensities depend linearly on the logarithm of DES concentrations in the range from 4.8×10? 4 to 36.0 nM with a detection limit of 0.025 pM. This novel assay is much more sensitive than other MIP sensors, and achieves lower cost and more enhanced stability than other immunosensors. The sensor is significantly potential and has been applied to DES detection in actual environment.
关键词： [Ru(bpy)3]2+-doped silica,Probe-mode ECL sensor,Core-shell QDs,Magnetically imprinted nanoparticles,Diethylstilbestrol,Single antibody sandwich-type
更新于2025-09-23 15:19:57
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Spectral photoluminescence properties of YAG: Ce, R (R: Gd3+, Pr3+, Gd3+ and Pr3+) transparent fluorescent thin film prepared by pulse laser deposition
摘要： In order to overcome the shortcomings of insufficient red light component and poor thermal stability of commercial white light emitting diode (WLED), YAG:Ce, R (R: Gd3t and Pr3t) fluorescent thin films were prepared by pulse laser deposition (PLD). The composition and microstructure, photoluminescence properties, and red-enhanced mechanism of co-doped YAG fluorescent thin films, as well as the electroluminescence behavior of the corresponding WLEDs were investigated. Results showed that the doping of Pr3t caused the emission spectrum energy of Ce3t to migrate, and an emission peak appeared at 606 nm in the red region. The doping of Gd3t caused the emission spectrum of Ce3t to shift to the red region, and the main peak position of the Ce3t emission spectrum is red-shifted from 523 nm to 548 nm. The YAG:Ce,Pr,Gd fluorescent film not only realized the improvement of red light components and red-shift, but also increased the energy transmission efficiency from 33.3% to 51.9%. Moreover, results of the color coordinate analysis also showed that the co-doping of Gd3t and Pr3t made the luminescence closer to the red region, reducing the color temperatures and hues changed to warm. Thus, tri-doped transparent fluorescent thin film were prospective for WLED application.
关键词： Photoluminescence properties,Transparent thin film,Pulse laser deposition,YAG:Ce,Tri-doped YAG
更新于2025-09-23 15:19:57
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Interactive tissue reactions of 1064a??nm focused picoseconda??domain laser and dermal cohesive polydensified matrix hyaluronic acid treatment in in vivo rat skin
摘要： Background: Picosecond-domain laser treatment using a microlens array (MLA) or a diffractive optical element (DOE) generates micro-injury zones in the epidermis and upper dermis. Objective: To investigate interactive tissue reactions between MLA-type picosecond laser pulses and cohesive polydensified matrix hyaluronic acid (CPMHA) filler in the dermis. Methods: In vivo rats with or without CPMHA pretreatment were treated with a 1064-nm picosecond-domain neodymium:yttrium-aluminum-garnet (Nd:YAG) laser using an MLA or DOE. Skin samples were obtained at post-treatment days 1, 10, and 21 and histologically and immunohistochemically analyzed. Results: Picosecond-domain Nd:YAG laser treatment with an MLA-type or a DOE-type handpiece generated fractionated zones of pseudo-cystic cavitation along the lower epidermis and/or upper papillary dermis at Day 1. At Day 21, epidermal thickness, dermal fibroblasts, and collagen fibers had increased. Compared to CPMHA-untreated rats, rats pretreated with CPMHA showed marked increases in fibroblasts and collagen fibers in the papillary dermis. Immunohistochemical staining for the hyaluronic acid receptor CD44 revealed that MLA-type picosecond laser treatment upregulated CD44 expression in the basilar epidermis and dermal fibroblasts. Conclusions: We suggest that the hyaluronic acid-rich environment associated with CPMHA treatment may enhance MLA-type picosecond-domain laser-induced tissue reactions in the epidermis and upper dermis.
关键词： laser,neodymium-doped yttrium aluminum garnet,cohesive polydensified matrix hyaluronic acid,laser-induced tissue breakdown,CD44,picosecond
更新于2025-09-23 15:19:57
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Dopant Activation of In Situ Phosphorusa??Doped Silicon Using Multia??Pulse Nanosecond Laser Annealing
摘要： Nanosecond laser annealing was performed on ISPD silicon in single- and multi-pulse modes. the active phosphorus concentration was increased with the laser power density and number of laser pulses and more phosphorus was activated with nanosecond lasers than with millisecond lasers. Moreover, almost all the incorporated phosphorus atoms were activated by the nanosecond laser without major strain loss when ISPD silicon melt
关键词： phosphorus-doped silicon,nanosecond laser annealing,diffusion,dopant activation,strain
更新于2025-09-23 15:19:57
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Controlled synthesis and panchromatic printing of highly luminescent NaYF4:Ln3+ upconversion hollow microtubes for information encryption on various packaging substrates
摘要： Lanthanide-ion doped β-NaYF4 crystals with bright and tunable upconversion luminescence are urgently demanded in anti-counterfeiting printing. Herein, novel highly luminescent hexagonal NaYF4:Ln3+ upconversion hollow microtubes (UCHMs) were controlled synthesized by a one-pot hydrothermal method employing poly(ethylene imine) (PEI) as ligand. The surface of the synthesized UCHMs was decorated by water-soluble polymer of PEI, rendering the hydrophilic nature of UCHMs. Besides, the synthesized UCHMs exhibited bright upconversion luminescence under the irradiation of a 980 nm laser due to the unique structure and morphology. Time-dependent morphology evolution showed that the formation of UCHMs experience a morphology change from nanoparticles to hexahedron to microprisms, and ultimately to microtubes via a dissolution-reconstruction formation mechanism. Furthermore, the resulting UCHMs were used as pigments for preparation of luminescent inks and their application in anti-counterfeiting printing was explored. To realize panchromatic printing, we prepared three-primary-color (RGB) UCHMs by rational tailoring the doping pairs and molar ratio of the lanthanide ions in UCHMs. Based on the superposition principle of the red-green-blue as three primary colors, a wide array of luminescent inks with panchromatic luminescent colors were prepared. The successful creation of securely light-responsive smart encryption patterns on various packaging substrates such as art paper, aluminum sheet, polyethylene terephthalate (PET) film and cardboard by screen printing was demonstrated. Our strategy provides a new route for controlled synthesis of hydrophilic UCHMs and the as-prepared UCHMs have great potential in application of packaging anti-counterfeiting.
关键词： Rare earth ion-doped NaYF4,Anti-counterfeiting,Hollow microtube,Screen printing,Hydrothermal
更新于2025-09-23 15:19:57
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Efficient non-doped blue fluorescent OLEDs based on bipolar phenanthroimidazole-triphenylamine derivatives
摘要： Blue organic emissive materials are still the most important bottlenecks for the development of organic light-emitting diodes (OLEDs). To enrich the material library, herin, three bipolar phenanthroimidazole derivatives, namely MePPIM-TPA, ClPPIM- TPA and BuPPIM-TPA, are synthesized using triphenylamine as electron-donor and phenanthroimidazole as the electron-acceptor. The photophysical, thermal and electrochemical properties of three compounds are investigated with high decomposition temperature up to 350 °C, and strong blue emission. Single-carrier devices are fabricated to show that three compounds have good bipolar carrier transport characteristic. The non-doped fluorescent OLEDs devices using three compounds as emitting layers are fabricated among which the devices based on MePPIM-TPA achieved the maximum luminance of 1743 cd/m2, the maximum external quantum efficiency (EQE) of 2.99% which is relatively comparable to commonly used blue emitters.
关键词： Non-doped OLEDs,Bipolar characteristic,Triphenylamine,Fluorescent materials,Phenanthroimidazole
更新于2025-09-23 15:19:57