- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Synthesis of Ultrathin Few-Layer 2D Nanoplates of Halide Perovskite Cs <sub/>3</sub> Bi <sub/>2</sub> I <sub/>9</sub> and Single-Nanoplate Super-Resolved Fluorescence Microscopy
摘要： The discovery of new two-dimensional (2D) perovskite halides has created sensation recently because of their structural diversity and intriguing optical properties. The toxicity of Pb-based perovskite halides led to the development of Pb-free halides. Herein, we have demonstrated a one-pot solution-based synthesis of 2D ultrathin (～1.78 nm) few-layer (2?4 layers) nanoplates (300?600 nm lateral dimension), nanosheets (0.6?1.5 μm), and nanocrystals of layered Cs3Bi2I9 by varying the reaction temperature from 110 to 180 °C. We have established a mechanistic pathway for the variation of morphology of Cs3Bi2I9 with temperature in the presence of organic capping ligands. Further, we have synthesized the bulk powder of Cs3Bi2I9 by mechanochemical synthesis and liquid-assisted grinding and crystalline ingot by vacuum-sealed tube melting. 2D nanoplates and bulk Cs3Bi2I9 demonstrate optical absorption edge along with excitonic transition. Photoluminescence properties of individual nanoplates were studied by super-resolution ?uorescence imaging, which indicated the blinking behavior down to the level of an individual Cs3Bi2I9 nanoplate along with its emission at the far-red region and high photostability.
关键词： ultrathin nanoplates,super-resolution ?uorescence imaging,two-dimensional (2D) perovskite halides,Pb-free halides,Cs3Bi2I9
更新于2025-09-09 09:28:46
-
[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - Initial Design of Phase-Frequency Scanned Array Using CRLH Leaky-Wave Antennas
摘要： Initial design of phase-frequency scanned array using composite right/left-handed (CRLH) waveguide leaky-wave antennas (LWAs) is studied in this paper. The array consists of 32 frequency scanning CRLH LWAs that are fed by a phased feed system. Two-dimensional (2D) beam steering capability is achieved in the plane normal to the array aperture and verified by the full-wave simulations. This array is capable of scanning to 61° from backward to forward directions in the frequency-scan plane and 17° in the phase-scan plane. The beamwidth is approximately 2° with ?20 dB sidelobe level (SLL) in the frequency-scan plane and 2.5° with maximum ?10 dB SLL in the phase-scan plane. Compared with traditional 2D scanning array, the feed system of this phase-frequency scanned array can be simplified significantly.
关键词： phase-frequency scanned array,leaky-wave antenna (LWA),two-dimensional (2D) beam steering,composite right/left-handed (CRLH),phased array
更新于2025-09-09 09:28:46
-
Chemical Vapor Deposition Growth of Single Crystalline CoTe <sub/>2</sub> Nanosheets with Tunable Thickness and Electronic Properties
摘要： Two-dimensional (2D) metallic transition metal dichalcogenides (MTMDs) have recently drawn increasing interest for fundamental studies and potential applications in catalysis, charge density wave (CDW), interconnections, spin-torque devices, as well superconductors. Despite some initial efforts, the thickness-tunable synthesis of atomically thin MTMDs remains a considerable challenge. Here we report controlled synthesis of 2D cobalt telluride (CoTe2) nanosheets with tunable thickness using an atmospheric pressure chemical vapor deposition (APCVD) approach and investigate their thickness-dependent electronic properties. The resulting nanosheets show a well-faceted hexagonal or triangular geometry with a lateral dimension up to ～200 μm. Systematic studies of growth at varying growth temperatures or flow rates demonstrate that nanosheets thickness is readily tunable from over 30 nm down to 3.1 nm. X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution scanning transmission electron microscope (STEM) studies reveal the obtained CoTe2 nanosheets are high-quality single crystals in the hexagonal 1T phase. Electrical transport studies show the 2D CoTe2 nanosheets display excellent electrical conductivities up to 4.0 × 105 S m?1 and very high breakdown current densities up to 2.1 × 107 A/cm2, both with strong thickness tunability.
关键词： Two-dimensional (2D),cobalt telluride (CoTe2),electronic properties,chemical vapor deposition (CVD),metallic transition metal dichalcogenides (MTMDs)
更新于2025-09-04 15:30:14