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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
  • FSO Communication System
  • Subcarrier Intensity Modulation
  • Atmospheric Turbulence
  • Bit Error Rate
  • Average Irradiance
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • Galgotias College of Engineering and Technology
347 条数据
?? 中文（中国） ▾

  • Physical origin of higher-order soliton fission in nanophotonic semiconductor waveguides

    摘要： Supercontinuum generation in Kerr media has become a staple of nonlinear optics. It has been celebrated for advancing the understanding of soliton propagation as well as its many applications in a broad range of fields. Coherent spectral broadening of laser light is now commonly performed in laboratories and used in commercial “white light” sources. The prospect of miniaturizing the technology is currently driving experiments in different integrated platforms such as semiconductor on insulator waveguides. Central to the spectral broadening is the concept of higher-order soliton fission. While widely accepted in silica fibers, the dynamics of soliton decay in semiconductor waveguides is yet poorly understood. In particular, the role of nonlinear loss and free carriers, absent in silica, remains an open question. Here, through experiments and simulations, we show that nonlinear loss is the dominant perturbation in wire waveguides, while free-carrier dispersion is dominant in photonic crystal waveguides.

    关键词： nonlinear optics,Supercontinuum generation,free-carrier dispersion,soliton fission,semiconductor waveguides

    更新于2025-11-28 14:24:03

  • Effect of Annealing Temperature on Structural, Morphological, Optical and Electrical Properties of Spray Deposited V2O5 Thin Films

    摘要： Nanostructured vanadium pentoxide (V2O5) thin films have been deposited by a simple and cost-effective spray pyrolysis technique (SPT) at substrate temperature 300 °C and post annealed at atmospheric conditions in the temperature range from 300 °C to 500 °C at a constant rate of heating. The influence of post annealing heat treatment on the crystallization of V2O5 has been investigated. Films were characterized structurally by X-ray diffraction, morphologically by Scanning electron microscopy, optically using UV-Vis spectrophotometer, electrical characterization using Hall probe and Raman spectroscopy has been carried out for phase confirmation. X-ray diffraction analysis (XRD) revealed that, as deposited films were orthorhombic structures with a preferential orientation along (0 0 1) direction. Moreover, it was observed that crystallite size increases from 22 nm to 56 nm with increase in annealing temperature. Optical properties of these samples were studied in the wavelength range 300 – 1000 nm. Raman spectrum confirms the layered structure of V2O5 thin films. Hall Effect measurements indicate that the change in carrier concentration with increase in annealing temperature.

    关键词： Raman spectroscopy,carrier density,annealing temperature,V2O5

    更新于2025-11-21 11:18:25

  • Two-dimensional beta-lead oxide quantum dots

    摘要： In recent years, black-phosphorus-analogue (BPA) two-dimensional (2D) materials have been explored to demonstrate promising optoelectronic performances and distinguished ambient stabilities, holding great promise in practical applications. Here, one new kind of BPA material, orthorhombic β-PbO quantum dots (QDs), is successfully fabricated by a facile liquid phase exfoliation (LPE) technique. The as-prepared β-PbO QDs show a homogeneous distribution of the lateral size (3.2 ± 0.9 nm) and thickness (2.5 ± 0.5 nm), corresponding to 4 ± 1 layers. The carrier dynamics of β-PbO QDs was systematically investigated via a femtosecond resolution transient absorption approach in the visible wavelength regime and it was clarified that two decay components were resolved with a decay time of τ1 = 2.3 ± 0.3 ps and τ2 = 87.9 ± 6.0 ps, respectively, providing important insights into their potential applications in the field of ultrafast optics, nanomechanics and optoelectronics. As a proof-of-concept, β-PbO QDs were, for the first time to our knowledge, fabricated as a working electrode in a photoelectrochemical (PEC)-typed photodetector that exhibits significantly high photocurrent density and excellent stability under ambient conditions.

    关键词： photoelectrochemical photodetector,β-PbO quantum dots,carrier dynamics,liquid phase exfoliation

    更新于2025-11-19 16:56:42

  • Manipulating the Phase Distributions and Carrier Transfers in Hybrid Quasi-Two-Dimensional Perovskite Films

    摘要： Quasi two-dimensional perovskites are promising alternatives to conventional three-dimensional perovskites because of their high stability and easy tunability. However, controlling the phase distribution according to device architecture remains a major challenge. Here, the manipulation of phase purity and vertical distribution proven by ultrafast transient absorption spectroscopy, and their effect on device characteristics are reported. By adding ethyl acetate as antisolvent, the growth direction of the perovskite film is flipped. CH3NH3Cl and dimethyl sulfoxide are used to slow the growth rate of the crystal, which gives better phase purity. The direction of carrier transfer is tuned accordingly. It is found that solar cell performance is more sensitive to phase purity relative to vertical distribution. These findings are of importance for the applications of quasi-2D perovskites in different types of devices that require to change phase purity and vertical distribution.

    关键词： solar cells,carrier transfer,vertical distribution,phase purity,quasi-2D perovskite

    更新于2025-11-19 16:56:35

  • Multi-scale ordering in highly stretchable polymer semiconducting films

    摘要： Stretchable semiconducting polymers have been developed as a key component to enable skin-like wearable electronics, but their electrical performance must be improved to enable more advanced functionalities. Here, we report a solution processing approach that can achieve multi-scale ordering and alignment of conjugated polymers in stretchable semiconductors to substantially improve their charge carrier mobility. Using solution shearing with a patterned microtrench coating blade, macroscale alignment of conjugated-polymer nanostructures was achieved along the charge transport direction. In conjunction, the nanoscale spatial confinement aligns chain conformation and promotes short-range π–π ordering, substantially reducing the energetic barrier for charge carrier transport. As a result, the mobilities of stretchable conjugated-polymer films have been enhanced up to threefold and maintained under a strain up to 100%. This method may also serve as the basis for large-area manufacturing of stretchable semiconducting films, as demonstrated by the roll-to-roll coating of metre-scale films.

    关键词： charge carrier mobility,conjugated polymers,solution shearing,stretchable semiconductors,roll-to-roll coating,multi-scale ordering

    更新于2025-11-19 16:56:35

  • Particle size effects of tetrahedron-shaped Ag3PO4 photocatalyst on water-oxidation activity and carrier recombination dynamics

    摘要： We investigated photocatalytic water-oxidation performance of tetrahedron-shaped silver phosphate (Ag3PO4) crystals with various particle sizes. The performance was clearly influenced by the particle size. The maximum activity was found for the particle with a tetrahedron edge with 1.5 μm length, which showed the highest rate of oxygen evolution. A series of analysis against time-resolved diffuse reflection spectra of the powder samples reveals that not only carrier recombination dynamic but also photoexcited carrier density can play important roles in the water oxidation. Our finding should contribute to give one of the basic ideas when designing semiconductor photocatalysts for water splitting.

    关键词： Silver phosphate,Photocatalytic water oxidation,Global analysis,Carrier dynamics

    更新于2025-11-19 16:51:07

  • Admittance of Organic LED Structures with an Emission YAK-203 Layer

    摘要： The current-voltage characteristics and admittance of multilayer structures for organic LEDs based on the PEDOT:PSS/NPD/YAK-203/BCP system have been experimentally investigated in a wide range of the measurement conditions. It is shown that at voltages corresponding to the effective radiative recombination of charge carriers, a significant decrease in the differential capacitance of the structures is observed. The frequency dependences of the normalized conductance of LED structures are in good agreement with the results of numerical simulation in the framework of the equivalent circuit method. Changes in the frequency dependences of the admittance with a change in temperature are most pronounced in the temperature range of 200–300 K and less noticeable in the temperature range of 8–200 K. From the frequency dependences of the imaginary part of impedance, the charge carrier mobilities are found at various voltages and temperatures. The mobility values obtained by this method are somewhat lower than those determined by the transient electroluminescence method. The dependence of the mobility on the electric field is well approximated by a linear function. As the temperature decreases from 300 to 220 K, the mobility decreases several times.

    关键词： frequency dependence of imaginary part of impedance,LED structure,current-voltage characteristic,transient electroluminescence,organic semiconductor,charge carrier mobility,method of equivalent circuits,admittance

    更新于2025-11-14 17:28:48

  • Surface decoration of BiOCl with BiVO<sub>4</sub> particles towards enhanced visible-light-driven photocatalytic performance

    摘要： BiVO4/BiOCl p-n junctioned photocatalysts were synthesized by surface replacement of pre-synthesized BiOCl with BiVO4 via a hydrothermal route. BiVO4 particles were decorated on the surface of BiOCl, the structures of which were favored of maximizing absorption of visible light. The photocatalytic activity of the heterojunctioned composites were evaluated by degradation of Rhodamine B (RhB) dye under visible light illumination. The results indicated that the composites exhibited superior efficiencies for RhB photodegradation in comparison with pure BiOCl, BiVO4 and BiOCl/BiVO4 with similar compositions. The 30% BiVO4/BiOCl exhibited an optimal photocatalytic activity due to the combinative effects of large visible-light absorbance and carrier separation. Experiments on scavenging active intermediates demonstrated that the enhanced photoactivity was primarily attributed to the formation of p-n junction. An effective built-in electric field was formed by the interface between p-type BiOCl and n-type BiVO4, which promoted the efficient separation of photoinduced electron-hole pairs.

    关键词： visible light absorption,BiVO4 decorated BiOCl,surface replacement,heterostructures,charge carrier separation

    更新于2025-11-14 17:04:02

  • Cu/Sb Codoping for Tuning Carrier Concentration and Thermoelectric Performance of GeTe-Based Alloys with Ultralow Lattice Thermal Conductivity

    摘要： Pristine GeTe shows promising thermoelectric performance but is limited by the high carrier concentration (nH) from Ge vacancies and thermal conductivity. Herein, Cu/Sb was chosen as codopants to suppress the high nH and to decrease thermal conductivity. In this condition, a promising zT of ～1.62 under 773 K was acquired in the Ge0.85Te(CuSb)0.075 system proposed in this paper/work. Results show that as the dopant concentration increases, the power factor rises due to the reduction of the nH to ～1 × 1020 cm?3. Apart from this, the total thermal conductivity also declines from ～7.4 W m?1 K?1 to ～1.59 W m?1 K?1 originating from an ultralow lattice thermal conductivity, in which the multiscatter mechanism from grain boundaries and point defect disperses the frequency phonons di?erently. The ?ndings in this paper combine thermal and electronic strategies and lay the foundation to develop Pb-free thermoelectric materials.

    关键词： multiscatter mechanism,Cu/Sb codoped GeTe,thermoelectric materials,ultralow lattice thermal conductivity,zT value,carrier concentration,Seebeck coefficient

    更新于2025-11-14 17:03:37

  • Green Synthesis of Carrier-Free Curcumin Nanodrugs for Light-activated Breast Cancer Photodynamic Therapy

    摘要： Photodynamic therapy (PDT) is a promising procedure for breast cancer therapy. Curcumin (Cur), a hydrophobic polyphenol derived from the spice turmeric, has been considered as a potential photosensitizer for PDT with evoked immune response, excellent safety, and low cost. However, the translation of curcumin in clinical cancer therapy suffers from an insufficient therapeutic dose in tumor tissues due to its poor solubility and low bioavailability. In this study, carrier-free curcumin nanodrugs (Cur NDs) were prepared without using any toxic solvents through a facile and green reprecipitation method. Cur NDs exhibited distinct optical properties, light-sensitive drug release behavior, resulting in increased reactive oxygen species (ROS) generation and PDT efficacy on breast cancer cells compared with free Cur. Furthermore, cell apoptosis during Cur-based PDT was concomitant with the activation of the ROS-mediated JNK/caspase-3 signaling pathway. Overall, our carrier-free Cur nanodrugs may be promising candidates for facilitating the efficacy and safety of PDT against breast cancer.

    关键词： Carrier-free,Curcumin,Light-responsive drug release,Breast cancer,Photodynamic therapy

    更新于2025-11-14 15:26:12