- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Spectral weights of mixed coupled plasmon modes in Dirac electron systems with different dimensionality
摘要： We study the effects of coupling between plasmon modes by the long-range Coulomb electron-electron interaction for a system consisting of a two-dimensional (2D) system of Dirac electrons embedded in three-dimensional (3D) Dirac semimetal. We obtain the dispersions of coupled plasmon modes for various separations of the subsystems. The coupled modes become more separated with decreasing the separation between two subsystems as the coupling increases due to the enhanced Coulomb interaction between electrons from different subsystems. We also demonstrate how the coupling affects the spectral weights of the obtained modes in two subsystems for different separations. In the 2D subsystem both coupled modes have finite weights for small wavenumbers, while for large wavenumbers only the upper mode persists. On the other hand, in the bulk this mode takes most of the spectral weight for small wavenumbers, while for large wavenumbers the lower mode is more pronounced.
关键词： plasmon modes,Coulomb interaction,spectral weights,Dirac electron systems
更新于2025-09-23 15:21:01
-
Interfacial and Bulk Properties of Hole Transporting Materials in Perovskite Solar Cells: Spiro-MeTAD versus Spiro-OMeTAD
摘要： Two spiro-MeTAD compounds (1 and 2) were synthesized, characterized by experimental and quantum mechanical methods, and used as hole transporting materials (HTMs) in perovskite solar cells (PSC). The new compounds differ from spiro-OMeTAD only by the presence of methyl substituents as compared to methoxy groups. This modification results in absorption-band blue shift by ~20 nm as compared to spiro-OMeTAD, increased glass transition temperature for 2, and reduced ionization potentials by 0.02-0.12 eV. Hole mobilities larger by five times were obtained for spiro-MeTAD /spiro-MeTAD, which is maintained in the presence of additives. Despite this improvement, J-V measurements in PSCs resulted in power conversion efficiency (PCE) of 17.2% and 17.05% for 1 and 2 HTMs, respectively, as compared to 19.24?% for spiro‐OMeTAD. Photoluminescence measurements of perovskite:HTM layers indicate much stronger quenching in the case of spiro-OMeTAD/spiro-MeTAD. These results point to the dominant importance of the perovskite/HTM interfacial properties as compared to HTM hole-transport properties in the bulk. Given that improved hole-mobility and energy-level alignment are the main targets of the current research efforts in this domain, our results alert on the necessity to give priority to improving perovskite-HTM interaction properties.
关键词： dft,perovskites,energy disorder,solar cells,interaction energy,interfaces
更新于2025-09-23 15:21:01
-
A comprehensive approach for characterisation of the deposited energy density during laser-matter interaction in liquids and solids
摘要： We present a novel approach for characterisation of ultrafast laser-matter interaction processes both in solids and liquids under extreme conditions of microplasma generation. By combination of three-dimensional propagation imaging, absorption measurements, shadowgraphy and photoacoustic imaging we can restore plasma electron density distribution, laser pulse fluence profile and the value of deposited energy density inside the bulk of the material and characterise the regime of the laser pulse propagation. The developped concept is important to understand the physics of ultrafast laser-matter interaction with strong implications for precision control of laser micromachining, bioprocessing and biotreatment.
关键词： three-dimensional propagation imaging,photoacoustics,femtosecond filamentation,laser-matter interaction,deposited energy density,shadowgraphy
更新于2025-09-23 15:21:01
-
CdSe/CdMnS Nanoplatelets with Bilayer Core and Magnetically Doped Shell Exhibit Switchable Excitonic Circular Polarization: Implications for Lasers and Light-Emitting Diodes
摘要： We utilized time-resolved photoluminescence (TRPL) spectroscopy to study the excitonic circular polarization (PX) from CdSe/CdMnS core/shell nanoplatelets (NPLs) with a bilayer core. This allows an extensive study of the emission dynamics as a function of magnetic ?eld, temperature, doping concentration, and excitation wavelength. In the presence of an external magnetic ?eld, pulsed excitation below the shell gap results in near-zero excitonic circular polarization PX at all time delays. In contrast, pulsed excitation with photon energy larger than the shell gap results in a rapid (100 ps) buildup of the excitonic circular polarization which subsequently remains constant at a level of up to 40%. We propose a model to describe the dynamics which takes into account the exchange interaction between carrier and magnetic ion (Mn) spins. The studied system exhibits a fast switchable excitonic circular polarization, implying possible applications in lasers and light emitting diodes.
关键词： spd exchange interaction,quasi-2D,time-resolved photoluminescence,nanoplatelets,magneto-optical switch
更新于2025-09-23 15:21:01
-
[IEEE 2019 E-Health and Bioengineering Conference (EHB) - Iasi, Romania (2019.11.21-2019.11.23)] 2019 E-Health and Bioengineering Conference (EHB) - New assistive technology for communicating with disabled people based on gaze interaction
摘要： Gaze interaction is a computer access method that allows disabled people to control a computer with their eyes. Gaze interaction only requires the movement of the eye itself—the movement of other muscles is not required, making it a perfect solution those with rehabilitative disabilities (paralysis, spinal cord injury, repetitive strain injury, severe carpal tunnel) and/or motor disabilities. The paper describes a simple software application of a new assistive device (Tobii eyeX tracker) and its evaluation for communicating with disabled people based on gaze interaction. The proposed communication method is developed as a part of a more complex integrated system for assistance in communicating with and telemonitoring severe neuromotor disabled patients.
关键词： gaze interaction,disabled people,eye tracking,assistive technology
更新于2025-09-23 15:21:01
-
Strongly Coupled Coherent Phonons in Single-Layer MoS <sub/>2</sub>
摘要： We present a transient absorption setup combining broadband detection over the visible-UV range with high temporal resolution (～20fs) which is ideally suited to trigger and detect vibrational coherences in different classes of materials. We generate and detect coherent phonons (CPs) in single layer (1L) MoS2, as a representative semiconducting 1L-Transition Metal Dichalcogenide (TMD), where the confined dynamical interaction between excitons and phonons is unexplored. The coherent oscillatory motion of the out-of-plane A'1 phonons, triggered by the ultrashort laser pulses, dynamically modulates the excitonic resonances on a timescale of few tens fs. We observe an enhancement by almost two orders of magnitude of the CP amplitude when detected in resonance with the C exciton peak, combined with a resonant enhancement of CP generation efficiency. Ab Initio calculations of the change in 1L-MoS2 band structure induced by the A'1 phonon displacement confirm a strong coupling with the C exciton. The resonant behavior of the CP amplitude follows the same spectral profile of the calculated Raman susceptibility tensor. These results explain the CP generation process in 1L-TMDs and demonstrates that CP excitation in 1L-MoS2 can be described as a Raman-like scattering process.
关键词： exciton-phonon interaction,Coherent phonons,transient absorption spectroscopy,transition metal dichalcogenides,ab-initio calculation
更新于2025-09-23 15:21:01
-
Laser fabrication of structural bone: surface morphology and biomineralization assessment
摘要： The current work explores the surface morphology of the laser-ablated bone using Yb-fiber coupled Nd:YAG laser (λ = 1064 nm) in continuous wave mode. As the laser-ablated region contains physiochemically modified carbonized and nonstructural region, it becomes unknown material for the body. Thus, biomineralization on such a laser-ablated region was assessed by in vitro immersion test in noncellular simulated body fluid. The presence of hydroxyapatite was detected in the precipitated mineral product using scanning electron microscopy equipped with energy dispersive spectroscopy, and X-ray diffraction analysis. The effect of varying laser parameters on distribution of surface morphology features was identified and its corresponding effect on biomineralization was studied.
关键词： Laser-bone interaction,Surface morphology,Finite element method (FEM) modeling,Laser ablation
更新于2025-09-23 15:21:01
-
Tailoring Component Interaction for Aira??Processed Efficient and Stable Alla??Inorganic Perovskite Photovoltaic
摘要： All-inorganic lead halide perovskites with potential stability improvement is promising candidate for optoelectronic applications. However, fundamental questions remain over the component interaction in the perovskite precursor solution due to the limitation of the most commonly used solvents of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Here, we report a simple and very effective interaction tailoring strategy for all-inorganic CsPbI3-xBrx perovskites by involving ionic liquid solvent methylammonium acetate (MAAc). We found that C=O has strong interaction with lead (Pb2+) and the N-H…I hydrogen bonds formation are observed. The interaction enables the stable perovskite precursor solution and allows the high-quality production of pinhole-free, large grain size, and flat all-inorganic perovskite films by retarding the crystallization. With a one-step, without the necessity for antisolvent treatment, air-processing approach regardless of humidity, the corresponding photovoltaic cell exhibits a high efficiency of 17.10% along with long operation stability over 1500 h under continuous light illumination.
关键词： photovoltaic,component interaction,all-inorganic perovskites,stability,ionic liquid solvent
更新于2025-09-23 15:21:01
-
Interaction of a phenazinium-based photosensitizer with surface active ionic liquid micelles: Investigating the effect of cyclodextrins on SAIL micelles
摘要： The present study depicts a spectroscopic investigation on the binding interaction of a phenazinium-based photosensitizer, phenosafranin (PSF) with a micelle forming surface active ionic liquid (SAIL), 1-butyl-3-methylimidazolium octyl sulfate (Bmim Os). The steady-state as well as time-resolved spectroscopic results reveal the binding of PSF with the micelles of the ionic liquid. The modulations of the spectral properties of PSF on interacting with Bmim Os micelles have been further employed to monitor the effect of various cyclodextrins, αCD, βCD and γCD (with varying dimensions of the hydrophobic cavity), on the Bmim Os micellar aggregates. The effective disruption of the Bmim Os micelles in presence of CDs is confirmed from the reduced size of Bmim Os micelles with added CD as observed from the DLS results.
关键词： Photosensitizer,Surface Active Ionic Liquid,Effect of Cyclodextrins,Binding Interaction,Bmim Os Micelles
更新于2025-09-23 15:21:01
-
Cowpea-structured PVDF/ZnO Nanofibers Based Flexible Self-powered Piezoelectric Bending Motion Sensor Towards Remote Control of Gestures
摘要： Interactive human-machine interface (iHMI) is a bridge connecting human beings and robots, which has an important requirement for perceiving the change of pressure and bending angle. Here, we designed a flexible self-powered piezoelectric sensor (PES) based on the cowpea-structured PVDF/ZnO nanofibers (CPZNs) for remote control of gestures in human-machine interactive system. Due to the synergistic piezoelectric effect of hybrid PVDF/ZnO and the flexibility of polymer, this PES exhibited excellent bending sensitivity of 4.4 mV deg-1 ranging widely from 44 ° to 122 °, fast response time of 76 ms, and good mechanical stability. Besides, the PES could operate under both bending and pressing mode, show ultrahigh pressing sensitivity of 0.33 V kPa-1, with response time of 16 ms. When integrated in iHMI, the PES could be conformably covered on different curve surfaces, demonstrated accurate bending angle recording and fast recognition for realizing intelligent human-machine interaction. On this basis, the application of remote control of robotic hand was successfully realized in form of acting the same gesture as human hand synchronously. This CPZNs-based self-powered PES is distinct and unique in its structure and fundamental mechanism, and exhibits a prospective potential application in iHMI.
关键词： human-machine interaction,cowpea-structured nanofiber,bending monitoring,self-powered,PVDF/ZnO
更新于2025-09-23 15:21:01