Search results for "Carrier mobility"
showing 7 items of 7 documents
Finite-size scaling of charge carrier mobility in disordered organic semiconductors
2016
Simulations of charge transport in amorphous semiconductors are often performed in microscopically sized systems. As a result, charge carrier mobilities become system-size dependent. We propose a simple method for extrapolating a macroscopic, nondispersive mobility from the system-size dependence of a microscopic one. The method is validated against a temperature-based extrapolation [A. Lukyanov and D. Andrienko, Phys. Rev. B 82, 193202 (2010)]. In addition, we provide an analytic estimate of system sizes required to perform nondispersive charge transport simulations in systems with finite charge carrier density, derived from a truncated Gaussian distribution. This estimate is not limited t…
Measurement of drift mobilities in amorphous organic films using the Time of Flight method
2004
We apply the Time of Flight (TOF) technique to study carrier mobility in N, N’-diphenyl-N,N’-bis(3-methylphenyl) -1,1-biphenyl-4,4’-diamine (TPD) and tris(8-hydroxyquinolato) aluminium (Alq 3 ). These materials are two examples of, respectively, hole and electron transporting molecular materials. Measurements are performed in free air or under vacuum varying the experimental parameters such as laser pulse intensity and single shot irradiation. We observe a transition from dispersive to non dispersive transport changing the experimental conditions.
Photoreactive Liquid Crystals in the Series of Dendritic and Cyclic Stilbenoid Compounds
2000
The dendrimers 1 and 2 and the areno-condensed annulenes 3 and 4 represent new mesogens for the generation of discotic mesophases. The stilbenoid building blocks of these compounds provide the molecular basis for interesting photochemical and photophysical effects like dimerisation, oligomerisation or the formation of charge carriers.
High-Mobility, Wet-Transferred Graphene Grown by Chemical Vapor Deposition
2019
We report high room-temperature mobility in single layer graphene grown by Chemical Vapor Deposition (CVD) after wet transfer on SiO$_2$ and hexagonal boron nitride (hBN) encapsulation. By removing contaminations trapped at the interfaces between single-crystal graphene and hBN, we achieve mobilities up to$\sim70000cm^2 V^{-1} s^{-1}$ at room temperature and$\sim120000cm^2 V^{-1} s^{-1}$ at 9K. These are over twice those of previous wet transferred graphene and comparable to samples prepared by dry transfer. We also investigate the combined approach of thermal annealing and encapsulation in polycrystalline graphene, achieving room temperature mobilities$\sim30000 cm^2 V^{-1} s^{-1}$. These …
ac conductivity inLa2CuO4
1992
Measurements of the complex ac conductivity are reported for a single crystal of ${\mathrm{La}}_{2}$${\mathrm{CuO}}_{4}$ for frequencies ${10}^{2}$\ensuremath{\le}\ensuremath{\nu}\ensuremath{\le}${10}^{9}$ Hz and temperatures 25\ensuremath{\le}T\ensuremath{\le}300 K. The conductivity follows a power-law behavior ${\mathrm{\ensuremath{\omega}}}^{\mathit{s}}$ with the frequency exponent s independent of temperature and independent of frequency. However, the hopping transport is strongly anisotropic, with s\ensuremath{\approxeq}0.75 within the ${\mathrm{CuO}}_{2}$ planes and s\ensuremath{\approxeq}0.25 perpendicular to the planes.
Bottom-Up, On-Surface-Synthesized Armchair Graphene Nanoribbons for Ultra-High-Power Micro-Supercapacitors
2020
Bottom-up-synthesized graphene nanoribbons (GNRs) with excellent electronic properties are promising materials for energy storage systems. Herein, we report bottom-up-synthesized GNR films employed as electrode materials for micro-supercapacitors (MSCs). The micro-device delivers an excellent volumetric capacitance and an ultra-high power density. The electrochemical performance of MSCs could be correlated with the charge carrier mobility within the differently employed GNRs, as determined by pump–probe terahertz spectroscopy studies.
Preparation of tungstophosphoric acid/cerium-doped NH2-UiO-66 Z-scheme photocatalyst: a new candidate for green photo-oxidation of dibenzothiophene a…
2021
International audience; The goal of this study was to introduce an effective visible-light induced photocatalytic system with a good ability for photocatalytic oxidative desulfurization (PODS) and denitrogenation (PODN) using molecular oxygen (O2) as an oxidant. In this regard, tungestophosphoric acid (PW12) was supported onto cerium-doped NH2-UiO-66 (PW12/Ce-NUiO-66) and employed for the photo-oxidation of dibenzothiophene (DBT) and quinoline (Qu). Herein, using cerium (Ce) as a “mediator” facilitated the separation of charge carriers, while NH2-UiO-66 remarkably enhanced the surface area with plentiful adsorption sites and shifted the adsorption edge of PW12to the visible region. The sum …