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oe1(光电查) - 科学论文

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出版时间
  • 2019
研究主题
  • Dye-sensitized solar cell
  • Hierarchical structure
  • Light scattering
  • TiO2 photoanode
应用领域
  • Nanomaterials and Technology
机构单位
  • National Sun Yat-sen University
  • Wenzao Ursuline University of Languages
149 条数据
?? 中文（中国） ▾

  • Effect of incorporation of sulphur on the structural, morphological and optical studies of CdSe thin films deposited by solution processed spin coating technique

    摘要： Ternary compound semiconductor CdSexS1-x (x = 1, 0.8, 0.6, 0.4, 0.2 and 0) thin films were prepared on glass substrates by using simple solution processed spin coating technique. Cadmium acetate, sodium selenosulfate and thiourea were used as source materials for Cd2+, Se2? and S2? ions, while triethanolamine was used as a capping agent. The 25% concentred NH4OH solution was used as a complex reagent and also used to adjust the pH of the final solution ~ 11. The deposition conditions (rotation speed 2000 rpm for 30 s and substrate dried in the air at 120 °C for 2 min) were remain same for all the samples. The as-deposited thin films on glass substrate were annealed at 350 °C for 30 min. The X-ray diffraction pattern shows that all the samples were polycrystalline in the nature with hexagonal structure. The most of prepared thin films were highly textured along (002) plane and peak position for plane (002) is shifted with change in composition ‘x’. The average crystallite size in CdSexS1-x thin films were found between 62.6 nm to 93.4 nm. Scanning electron microscopy images showed uniform deposition morphology with spherical shaped grains distributed over entire glass substrate. Samples CdSe0.8S0.2 and CdSe0.6S0.4 thin films indicated interesting morphological features with the combination of spherical shaped nanoparticles and interconnected nanofibers which form hierarchical flowerlike micro-structure. Energy dispersive X-Ray studies confirmed that thin films were having approximately same stoichiometry of atomic ratio of elements Cd, Se and S as present in volumetric ratio of the reactants in chemical solution. Fourier transform infrared studies confirmed the formation of the Cd(Se,S) bonding in materials. The optical band gap of CdSexS1-x thin films were found as direct band gap in the range of 1.82 eV to 2.32 eV. As the incorporation of sulphur element increases, the band gap of CdSexS1-x thin film also increases. The CdSexS1-x thin films can be used as absorption layer in solar photovoltaic cell which is due to wide and fine tenability of the energy band gap.

    关键词： Nanofibers,Spin coating,Absorption layer,cadmium sulfide,Cadmium selenide,Hierarchical flowerlike microstructure,Ternary compound semiconductor

    更新于2025-11-21 11:18:25

  • Hollow hierarchical structure Co0.85Se as efficient electrocatalyst for the triiodide reduction in dye-sensitized solar cells

    摘要： The exploration of nonprecious metal-based electrocatalysts with high efficiency for the triiodide reduction is critical for the practical applications of the dye-sensitized solar cells. Herein, we develop a facile one-step hydrothermal method to synthesize hollow hierarchical structure Co0.85Se. Under the methanol-water reaction system, the product named as hollow hierarchical structure Co0.85Se-M has the largest specific surface area (215.36 m2 g?1) and the best crystallinity than other products obtained from other alcohol-water reaction systems. When this electrocatalyst is applied as a counter electrode for the dye-sensitized solar cells, it exhibits a small peak-to-peak separation (Epp, 97 mV) for the reduction of I3?/I? redox couple. It is found that the catalytic activity of Co0.85Se is closely dependent on the crystallinity. Moreover, the reactivity pathway is identified by density functional theory, which confirms that triiodide is reduced to iodide ion on Co0.85Se with a smaller energy barrier (～0.65 eV) than on Pt (～1.18 eV). Both experimental and theoretical results demonstrate Co0.85Se-M as an ideal counter electrode material for the dye-sensitized solar cells with a higher power conversion efficiency (8.76%) than Pt counter electrode (7.20%).

    关键词： Dye-sensitized solar cells,Hollow hierarchical structure,Cobalt selenides,Electrocatalytic activity,Triiodide reduction

    更新于2025-11-21 11:03:13

  • Tessellation of Chiral-Nematic Cellulose Nanocrystal Films by Microtemplating

    摘要： In biological architectures, material properties are optimized by the hierarchical structuring of components with a multiscaled order, from the nano- to the macroscales. Such designs enable, for instance, programmed yield points that maximize toughness. However, research efforts in biomimetic materials have focused on the assembly of nano- or macrostructures individually. In this study, high strength cellulose nanocrystals (CNCs), assembled into chiral-nematically ordered structures, are tiled into a higher level, macro-sized, architecture by topographical templating. As templates, two meshed architectures with distinct feature sizes are evaluated, and the optomechanical properties of the resulting films are compared to featureless, flat, CNC films. Controlling capillary stresses arising during CNC assembly is shown to enable control over the orientation of the chiral-nematic director across the topography of the template. Tuning the specific reflections and multiscaled fracture propagation is demonstrated for the microtemplated CNC films. The latter phenomenon contributed to enhancing the toughness of the material through a high tortuosity of fracture propagation in all (x, y, z) directions. The presented findings are expected to pave the way towards the incorporation of current research in cellular metamaterials with the research focusing on the generation of nanoscaled biomimetic constructs.

    关键词： tessellation,conformability,biomimetic,hierarchical,cellulose nanocrystals

    更新于2025-11-21 11:01:37

  • Hierarchical TiO <sub/>2</sub> microspheres composed with nanoparticle-decorated nanorods for the enhanced photovoltaic performance in dye-sensitized solar cells

    摘要： Hierarchical TiO2 microspheres composed of nanoparticle-decorated nanorods (NP-MS) were successfully prepared with a two-step solvothermal method. There were three benefits associated with the use of NP-MS as a photoanode material. The decoration of nanoparticles improved the specific surface area and directly enhanced the dye loading ability. Rutile nanorods serving as electron transport paths resulted in fast electron transport and inhibited the charge recombination process. The three-dimensional hierarchical NP-MS structure supplied a strong light scattering capability and good connectivity. Thus, the hierarchical NP-MS combined the beneficial properties of improved scattering capability, dye loading ability, electron transport and inhibited charge recombination. Attributed to these advantages, a photoelectric conversion efficiency of up to 7.32% was obtained with the NP-MS film-based photoanode, resulting in a 43.5% enhancement compared to the efficiency of the P25 film-based photoanode (5.10%) at a similar thickness. Compared to traditional photoanodes with scattering layers or scattering centers, the fabrication process for single layered photoanodes with enhanced scattering capability was very simple. We believe the strategy would be beneficial for the easy fabrication of efficient dye-sensitized solar cells.

    关键词： electron transport,dye-sensitized solar cells,solvothermal method,Hierarchical TiO2 microspheres,photovoltaic performance

    更新于2025-11-14 17:04:02

  • Preparation of hierarchical flower-like nickel sulfide as hole transporting material for organic solar cells via a one-step solvothermal method

    摘要： In this work, nickel sulfide (NiS) with a mesoporous network was prepared through a simple solvothermal approach. The influences of various contents of the sulfur source on the morphological changes were examined. Finally, the resultant NiS doped with various contents of sulfur were used as hole-transport layers (HTLs) for the application to organic solar cells (OSCs). Based on our knowledge of the implementation of OSCs, NiS-based HTLs are used for the first time in this paper. The OSCs developed with NiS_2.0 (NiS doped with 2.0 g of thioacetamide (sulfur source)) HTL showed a higher PCE response, at 2.28% than those fabricated with NiS_1.0 (NiS doped with 1.0 g of thioacetamide), NiS_1.5, (NiS doped with 1.5 g of thioacetamide), and NiS_2.5 (NiS doped with 2.5 g of thioacetamide), which only showed 1.38%, 1.88%, and 1.96%, respectively. Besides this improved photovoltaic response, it also demonstrated a superior reproducibility with a high degree of control over the environmental stability, i.e., 360 h, as compared to the bare PEDOT:PSS HTL-based OSCs, which showed just 240 h.

    关键词： Stability,Reproducibility,Synthesis,Hole transport layer,Organic solar cells,Hierarchical flower-like nickel sulfide

    更新于2025-11-14 17:04:02

  • Double-layered hierarchical titanate and its attaching and splitting mechanism

    摘要： Double-layered hierarchical titania materials exhibit outstanding properties. However, most hydrothermal synthesis methods of bilayer hierarchical titania materials are time-consuming and high alkali-consuming. In this study, a less alkali-consuming one-pot method was developed to synthesize bilayer hierarchical titanate, specifically, 1D nanoarray layer and 3D hierarchical layer. Morphologies of the composites can be manipulated by varying hydrothermal conditions and introducing titanate nuclei based on the attachment rule and splitting mechanism. More importantly, splitting phenomena were observed and confirmed in both nanosheet-to-nanowire transformation process and nanowire-to-nanotube transformation process. It was firstly confirmed that the driving force of the splitting process is the transformation from amorphous state titanate to crystalline state titanate.

    关键词： 1D nanostructures,Splitting mechanism,Hierarchical titanate,Attaching mechanism

    更新于2025-11-14 17:03:37

  • In Situ Generation of AgI Quantum Dots by the Confinement of A?Supramolecular Polymer Network: A Novel Approach for Ultrasensitive Response

    摘要： Currently, it is difficult to realize environmentally friendly synthesis of zeolites due to the use of the solvent. Therefore, it is of great importance to realize zeolite synthesis from iron ore tailings (IOTs) by a solvent-free method. In this work, in situ formed zeolite crystals are self-assembled and IOTs are converted into hierarchically porous ZSM-5. After that, the products prepared are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and nitrogen adsorption. The results demonstrate that the samples show well-defined crystallinity and have micro-/mesoporous structures. The BET surface area is estimated to be 319.809 m2 g?1 and the external surface area is 92.693 m2 g?1, which indicate the as-synthesized ZSM-5 is a good hierarchically porous material. This work provides a reference for green synthesis of hierarchically porous ZSM-5 from IOT.

    关键词： Hierarchical structure,Iron ore tailings,Solvent-free method,ZSM-5

    更新于2025-11-14 15:15:56

  • Casimir-Lifshitz quantum state of superhydrophobic black-silicon surfaces manufactured by a metal-assisted hierarchical nano-microtexturing process

    摘要： We investigated superhydrophobic Si nanosurfaces similar to the lotus leaf by performing a hierarchical nanotexturing process on micropyramidal Si surfaces. The process was carried out using a metal-assisted chemical etching process based upon the deposition of Ag nanoparticles. The hierarchical micro-nanosurfaces showed a superhydrophobic character with contact angles of approximately 134～150°. The photon tunnelling also provides a strong light absorption as a black Si. The surface-light emission from broad and sharp photoluminescence was observed in the wavelength ranges of 414.7～440 and 509～516.2 nm. The ?eld-induced tunnelling current on nanosurface shows the formation of quantum surface states. From the analyses of Casimir-Lifshitz quantum state of a photon in vacuum, the superhydrophobic behaviour of water droplet is closely related to the nanosurface and the nanoporous cavity shows the absorption of terahertz energy. Si nanosurface shows the broadband absorption in the spectral range of 800～900 cm?1 corresponding to the energy range of 99.2～111.6 meV with 24～27 THz.

    关键词： Metal-assisted etching,hierarchical nano-microstructure,Ag nanodot deposition,superhydrophobic nanosurface

    更新于2025-11-14 15:14:40

  • Ultraviolet patterns of flowers revealed in polymer replica – caused by surface architecture

    摘要： Angiosperms and their pollinators are adapted in a close co-evolution. For both the plants and pollinators, the functioning of the visual signaling system is highly relevant for survival. As the frequency range of visual perception in many insects extends into the ultraviolet (UV) region, UV-patterns of plants play an important role in the flower–pollinator interaction. It is well known that many flowers contain UV-absorbing pigments in their petal cells, which are localized in vacuoles. However, the contribution of the petal surface microarchitecture to UV-reflection remains uncertain. The correlation between the surface structure and its reflective properties is also relevant for biomimetic applications, for example, in the field of photovoltaics. Based on previous work, we selected three model species with distinct UV-patterns to explore the possible contribution of the surface architecture to the UV-signaling. Using a replication technique, we transferred the petal surface structure onto a transparent polymer. Upon illumination with UV-light, we observed structural-based patterns in the replicas that were surprisingly comparable to those of the original petals. For the first time, this experiment has shown that the parameters of the surface structure lead to an enhancement in the amount of absorbed UV-radiation. Spectrophotometric measurements revealed up to 50% less reflection in the UV-absorbing regions than in the UV-reflecting areas. A comparative characterization of the micromorphology of the UV-reflecting and UV-absorbing areas showed that, in principle, a hierarchical surface structure results in more absorption. Therefore, the results of our experiments demonstrate the structural-based amplification of UV-reflection and provide a starting point for the design of bioinspired antireflective and respectively strongly absorbing surfaces.

    关键词： hierarchical structures,biomimetics,light absorption,light harvesting,light reflection

    更新于2025-10-22 19:40:53

  • Engineering Charge Transfer Characteristics in Hierarchical Cu2S QDs @ ZnO Nanoneedles with p–n Heterojunctions: Towards Highly Efficient and Recyclable Photocatalysts

    摘要： Equipped with staggered gap p-n heterojunctions, a new paradigm of photocatalysts based on hierarchically structured nano-match-shaped heterojunctions (NMSHs) Cu2S quantum dots (QDs)@ZnO nanoneedles (NNs) are successfully developed via engineering the successive ionic layer adsorption and reaction (SILAR). Under UV and visible light illumination, the photocatalytic characteristics of Cu2S@ZnO heterojunctions with different loading amounts of Cu2S QDs are evaluated by the corresponding photocatalytic degradation of rhodamine B (RhB) aqueous solution. The results elaborate that the optimized samples (S3 serial specimens with six cycles of SILAR reaction) by means of tailored the band diagram exhibit appreciable improvement of photocatalytic activities among all synthesized samples, attributing to the sensitization of a proper amount of Cu2S QDs. Such developed architecture not only could form p–n junctions with ZnO nanoneedles to facilitate the separation of photo-generated carries but also interact with the surface defects of ZnO NNs to reduce the electron and hole recombination probability. Moreover, the existence of Cu2S QDs could also extend the light absorption to improve the utilization rate of sunlight. Importantly, under UV light S3 samples demonstrate the remarkably enhanced RhB degradation efficiency, which is clearly testified upon the charge transfer mechanism discussions and evaluations in the present work. Further supplementary investigations illustrate that the developed nanoscale Cu2S@ZnO heterostructures also possess an excellent photo-stability during our extensive recycling photocatalytic experiments, promising for a wide range of highly efficient and sustainably recyclable photocatalysts applications.

    关键词： Photocatalysis,QDs,ZnO@Cu2S hierarchical structure,Photostability,p-n heterojunctions

    更新于2025-09-23 15:23:52