- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Orientation‐Controlled 2D Anisotropic and Isotropic Photon Transport in Cocrystal Polymorph Microplates
摘要： Two-dimensional (2D) anisotropic transport of photons/electrons is crucial for constructing ultracompact on-chip circuits. To date, the photons in organic 2D crystals usually exhibit the isotropic propagation, and the anisotropic behaviors have not yet been fully demonstrated. Herein, an orientation-controlled photon-dipole interaction strategy was proposed to rationally realize the anisotropic and isotropic 2D photon transmissions in two self-assembled cocrystal polymorph microplates. The monoclinic microplate adopting a nearly horizontal molecular transition dipole orientation in the 2D plane, exhibits anisotropic photon-dipole interactions and thus distinct re-absorption waveguide losses for different 2D directions. By contrast, the triclinic microplate with a vertical transition dipole orientation, shows the 2D isotropic photon-dipole interactions and thus the same re-absorption losses along different directions. Based on the anisotropic transport mechanism, a directional signal outcoupler (DSO) was further designed for the high-fidelity transmission of the real signals, which would enlighten the development of 2D anisotropic optical devices.
关键词： transition dipole moment,Cocrystal,polymorphs,two-dimensional photonics,anisotropic optical waveguides
更新于2025-09-16 10:30:52
-
Efficient Two-Dimensional Tin Halide Perovskite Light-Emitting Diodes via a Spacer Cation Substitution Strategy
摘要： Lead halide perovskites have attracted tremendous attention due to their impressive optoelectronic properties. However, the toxicity of lead remains to be a bottleneck for further commercial development. Two-dimensional Ruddlesden-Popper tin-based perovskites are lead-free and more stable compared to their 3D counterparts, which have great potential in the optoelectronic device field. Herein, we demonstrated high-quality 2D phenylethyl ammonium tin-iodide perovskite (PEA2SnI4) thin films by dropping toluene as anti-solvent. Furthermore, the PeLED performance is greatly improved by replacing PEAI spacer cation with 2-thiopheneethyllamine iodide (TEAI). As a result, the TEA-based PeLED device is achieved with a low turn-on voltage of 2.3V, a maximum luminance of 322 cd m-2 and maximum external quantum efficiency of 0.62%, which is the highest efficiency and brightness for pure red (emission peak=638 nm) tin-based PeLEDs so far.
关键词： pure red light-emitting diodes,two-dimensional tin-based perovskite,spacer cation substitution
更新于2025-09-16 10:30:52
-
Improved Charge Injection and Transport of Light-Emitting Diodes Based on Two-Dimensional Materials
摘要： Light-emitting diodes (LEDs) are considered to be the most promising energy-saving technology for future lighting and display. Two-dimensional (2D) materials, a class of materials comprised of monolayer or few layers of atoms (or unit cells), have attracted much attention in recent years, due to their unique physical and chemical properties. Here, we summarize the recent advances on the applications of 2D materials for improving the performance of LEDs, including organic light emitting diodes (OLEDs), quantum dot light emitting diodes (QLEDs) and perovskite light emitting diodes (PeLEDs), using organic ?lms, quantum dots and perovskite ?lms as emission layers (EMLs), respectively. Two dimensional materials, including graphene and its derivatives and transition metal dichalcogenides (TMDs), can be employed as interlayers and dopant in composite functional layers for high-e?ciency LEDs, suggesting the extensive application in LEDs. The functions of 2D materials used in LEDs include the improved work function, e?ective electron blocking, suppressed exciton quenching and reduced surface roughness. The potential application of 2D materials in PeLEDs is also presented and analyzed.
关键词： perovskite light emitting diodes,quantum dot light emitting diodes,organic light emitting diodes,two-dimensional materials
更新于2025-09-16 10:30:52
-
2D Bragg Resonators Based on Planar Dielectric Waveguides (from Theory to Model-Based Testing)
摘要： Using analytical approaches and CST Microwave Studio 3D simulation, the electrodynamic characteristics of 2D Bragg resonators based on planar dielectric waveguides with doubly periodic corrugation are theoretically analyzed. Such resonators are of great interest to obtain directed narrow-band radiation in heterolasers with large active regions. Model electrodynamic experiments on the “cold” testing of such structures in the millimeter range are performed. Good agreement between the experimental and simulation results is shown, including the existence of the highest-Q mode within the Bragg reflection band in the absence of defects in the periodicity.
关键词： planar dielectric waveguides,two-dimensional distributed feedback,heterolasers
更新于2025-09-16 10:30:52
-
Tunable Photoresponse by Gate Modulation in Bilayer Graphene Nanoribbon Devices
摘要： Control of absorption and photocurrent conversion is of practical importance for the design of photoelectric devices. In this paper, using simulations, we demonstrate that the photoresponse of a bilayer graphene nanoribbon (GNR) device can be controlled by gate voltage modulation. A vertical gate ?eld shifts the potential on the top and bottom layers in opposite directions, resulting in a continuous change of band gap with applied gate voltage. This ?eld simultaneously facilitates separation of photoexcited electron?hole pairs and gives rise to a photocurrent in a selected photon energy range. The photoresponse of a bilayer GNR device can thus be tuned by adjusting the applied gate voltage. In addition, the light frequency range can be changed by using nanoribbons of di?erent widths. These ?ndings provide a basis for the design of adjustable optoelectronic devices using two-dimensional materials.
关键词： optoelectronic devices,gate modulation,graphene nanoribbon,two-dimensional materials,photoresponse
更新于2025-09-12 10:27:22
-
Modulated photonic-crystal surface-emitting laser with elliptical lattice points for two-dimensional coupling enhancement
摘要： Modulated photonic-crystal surface-emitting lasers (M-PCSELs) are new semiconductor lasers that can emit a laser beam in arbitrary directions. Therefore, they can be regarded as a next-generation light source for light detection and ranging. In this manuscript, we numerically investigate the characteristics of M-PCSELs, including one- and two-dimensional optical coupling constants and radiation constants, by using three-dimensional coupled wave theory. We also carry out lattice point designs and show that the two-dimensional optical coupling can be enhanced by more than four times over our previous M-PCSEL devices by employing elliptical lattice points. Moreover, we find that two-dimensional optical coupling can be maintained even when large lattice point position modulations are introduced for large radiation constants. These results indicate that more stable two-dimensional oscillation and a higher slope efficiency are expected in M-PCSELs with elliptical lattice points.
关键词： elliptical lattice points,M-PCSELs,radiation constants,Modulated photonic-crystal surface-emitting lasers,two-dimensional optical coupling
更新于2025-09-12 10:27:22
-
Theoretical and experimental studies of highly selective planar two-dimensional Bragg structures based on dielectric waveguides in the terahertz frequency range
摘要： Based on theoretical approach and three-dimensional modeling using the CST Microwave Studio code, planar dielectric two-dimensional Bragg structures in terahertz frequency range were developed and manufactured. Proof-of-principle electrodynamic experiments on the “cold” testing of these structures were carried out. It is shown that the experimental results are in good agreement with the theoretical predicts, including the existence of the highest Q mode inside the Bragg reflection band in the absence of periodicity defects.
关键词： CST Microwave Studio,Bragg reflection band,planar dielectric two-dimensional Bragg structures,terahertz frequency range,electrodynamic experiments
更新于2025-09-12 10:27:22
-
Two-dimensional hydrogenated buckled gallium arsenide: An <i>ab-initio</i> study
摘要： First-principles calculations have been carried out to investigate the stability, structural and electronic properties of two?dimensional hydrogenated GaAs with three possible geometries: chair, zigzag?line and boat con?gurations. The e?ect of van der Waals interactions on 2D H?GaAs systems has also been studied. These con?gurations were found to be energetic and dynamic stable, as well as having a semiconducting character. Although two?dimensional GaAs adsorbed with H tends to form a zigzag?line con?guration, the energy di?erences between chair, zigzag?line and boat are very small which implies the metastability of the system. Chair and boat con?gurations display a Γ?Γ direct bandgap nature, while pristine 2D?GaAs and zigzag?line are indirect semiconductors. The bandgap sizes of all con?gurations are also hydrogen dependent, and wider than that of pristine 2D?GaAs with both PBE and HSE functionals. Even though DFT?vdW interactions increase the adsorption energies and reduce the equilibrium distances of H?GaAs systems, it presents, qualitatively, the same physical results on the stability and electronic properties of our studied systems with PBE functional. According to our results, two?dimensional buckled gallium arsenide is a good candidate to be synthesized by hydrogen surface passivation as its group III?V partners two-dimensional buckled gallium nitride and boron nitride. The hydrogenation of 2D-GaAs tunes the bandgap of pristine 2D-GaAs, which makes it a potential candidate for optoelectronic applications in the blue and violet ranges of the visible electromagnetic spectrum.
关键词： two-dimensional gallium arsenide.,hydrogen,bandgap tuning,Density Functional Theory
更新于2025-09-12 10:27:22
-
EXPRESS: Two-Dimensional Temperature Measurement in a High Temperature and Pressure Combustor Using Computed Tomography Tunable Diode Laser Absorption Spectroscopy (CT-TDLAS) with a Wide-Scanning Laser at 1335–1375 nm
摘要： Tunable diode laser absorption spectroscopy (TDLAS) technology is a developing method for temperature and species concentration measurements with the features of non-contact, high precision, high sensitivity, etc. The difficulty of two-dimensional (2D) temperature measurement in actual combustors has not yet been solved because of pressure broadening of absorption spectra, optical accessibility, etc. In this study, the combination of computed tomography (CT) and TDLAS with a wide scanning laser at 1335–1375 nm has been applied to a combustor for 2D temperature measurement in high temperature of 300–2000 K and high pressure of 0.1–2.5 MPa condition. An external cavity type laser diode with wide wavelength range scanning at 1335–1375 nm was used to evaluate the broadened H2O absorption spectra due to the high temperature and high pressure effect. The spectroscopic database in high temperature of 300–2000 K and high pressure of 0.1–5.0 MPa condition has been revised to improve the accuracy for temperature quantitative analysis. CT reconstruction accuracy was also evaluated in different cases, which presented the consistent temperature distribution between CT reconstruction and assumed distributions. The spatial and temporal distributions of temperature in the high temperature and high pressure combustor were measured successfully by CT-TDLAS using the revised spectroscopic database.
关键词： high temperature and high pressure field,TDLAS,computed tomography,2D,Two-dimensional temperature measurement,combustion,CT,tunable diode laser absorption spectroscopy
更新于2025-09-12 10:27:22
-
MXenes induce epitaxial growth of size-controlled noble nanometals: a case study for surface enhanced Raman scattering (SERS)
摘要： Noble nanometals are of significance in both scientific interest and technological applications, which are usually obtained by conventional wet-chemical synthesis. Organic surfactants are always used in the synthesis to prevent unexpected overgrowth and aggregation of noble nanometals. However, the surfactants are hard to remove and may interfere with plasmonic and catalytic studies, remaining surfactant-free synthesis of noble nanometals a challenge. Herein, we report an approach to epitaxial growth of size-controlled noble nanometals on MXenes. As piloted by density functional theory calculations, along with work function experimental determination, kinetic and spectroscopic studies, epitaxial growth of noble nanometals is initiated via a mechanism that involves an in situ redox reaction. In the redox, MXenes as two-dimensional solid reductants whose work functions are compatible with the reduction potentials of noble metal cations, enable spontaneous donation of electrons from the MXenes to noble metal cations and reduce the cations into nanoscale metallic metals on the outmost surface of MXenes. Neither surfactants nor external reductants are used during the whole synthesis process, which addresses a long-standing interference issue of surfactant and external reductant in the conventional wet-chemical synthesis. Moreover, noble nanometals are size-controlled. Impressively, noble nanometals firmly anchored on MXenes exhibit excellent performance towards surface enhanced Raman scattering. Our developed strategy will promote the nanostructure-controlled synthesis of noble nanometals, offering new opportunities to further improve advanced functional properties towards practical applications.
关键词： SERS,Two-dimensional materials,MXene,In situ redox,Noble metal
更新于2025-09-12 10:27:22