scholarly journals Population dependence of THz charge carrier mobility and non-Drude-like behavior in short semiconductor nanowires

Nanoscale ◽  
2021 ◽  
Author(s):  
Alexander W. Achtstein ◽  
Nina Owschimikow ◽  
Michael Tiberius Quick
Keyword(s):  
Charge Carrier ◽  
Carrier Mobility ◽  
Charge Carrier Mobility ◽  
Semiconductor Nanowires ◽  
Charge Carriers ◽  
Radiation Absorption ◽  
Thz Radiation

We investigate THz radiation absorption by charge carriers, focusing on the mobility in nanorods and wires. We show that for short rods the mobility is limited by the high spacing...

Phase Segregation via Etching-Induced Cation Migration in CoSx-ZnS Nanoarchitectures for Solar Hydrogen Evolution

2022 ◽  
Author(s):  
Zirong Shen ◽  
Junmin Huang ◽  
Junying Chen ◽  
Yingwei Li
Keyword(s):  
Photocatalytic Activity ◽  
Charge Carrier ◽  
Hydrogen Evolution ◽  
Carrier Mobility ◽  
Phase Segregation ◽  
Charge Carrier Mobility ◽  
Charge Carriers ◽  
Solar Hydrogen ◽  
Cation Migration ◽  
Low Charge

Low charge carrier mobility limits the development of highly efficient semiconductor-based photocatalysis. Heterointerface engineering is a promising approach to spatially separate the photoexcited charge carriers and thus enhance photocatalytic activity....

scholarly journals Charge carrier mobility dynamics in organic semiconductors and solar cells

2020 ◽  
Vol 60 (1) ◽  
Author(s):  
Vidmantas Gulbinas
Keyword(s):  
Solar Cells ◽  
Charge Carrier ◽  
Organic Semiconductors ◽  
Organic Solar Cells ◽  
Carrier Mobility ◽  
Charge Carrier Mobility ◽  
Charge Carriers ◽  
Organic Layer ◽  
Stoichiometric Ratio ◽  
Donor And Acceptor

Charge carrier mobility in organic semiconductors is not a constant value unambigously characterizing some particular material, but depends on the electric field, temperature and even on time after it was generated or injected. The time dependence is particularly important for the thin-film devices where charge carriers pass the organic layer before mobility reaching its stationary value. Here we give a review of experimental techniques with ultrafast timeresolution enabling one to address the mobility kinetics and analyse properties of the time-dependent mobility in conjugated polymers and organic solar cells. We analyse kinetics during the charge carrier generation and extraction of free charge carriers. The mobility typically decreases by several orders of magnitude on a picosecond-nanosecond time scale; however, its kinetics also depends on the investigation technique. The mobility kinetics in blends for bulk heterojunction solar cells strongly depends on the stoichiometric ratio of donor and acceptor materials.

Charge carrier mobility in one-dimensional aligned π-stacks of conjugated small molecules with a benzothiadiazole central unit

2017 ◽  
Vol 19 (12) ◽  
pp. 8330-8339 ◽  
Author(s):  
Deyan Raychev ◽  
Olga Guskova
Keyword(s):  
Charge Carrier ◽  
Small Molecules ◽  
Carrier Mobility ◽  
Charge Carrier Mobility ◽  
Charge Carriers ◽  
Central Unit ◽  
Dft Methods ◽  
Crystalline Materials ◽  
One Dimensional ◽  
Mobility Of Charge Carriers

The hopping mobility of charge carriers in organic crystalline materials consisting of benzothiadiazole-cored molecules with thiophene or furan flanks was analyzed using DFT methods.

scholarly journals The Quinonoid Zwitterion Interlayer for the Improvement of Charge Carrier Mobility in Organic Field-Effect Transistors

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1567
Author(s):  
Adam Luczak ◽  
Angélina Ruiz ◽  
Simon Pascal ◽  
Adrian Adamski ◽  
Jarosław Jung ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Field Effect ◽  
Carrier Mobility ◽  
Field Effect Transistors ◽  
Charge Carrier Mobility ◽  
Charge Carriers ◽  
Organic Field Effect Transistors ◽  
Order Of Magnitude ◽  
Charge Carrier Trapping ◽  
Trapping Sites

The interface between the semiconductor and the dielectric layer plays a crucial role in organic field-effect transistors (OFETs) because it is at the interface that charge carriers are accumulated and transported. In this study, four zwitterionic benzoquinonemonoimine dyes featuring alkyl and aryl N-substituents were used to cover the dielectric layers in OFET structures. The best interlayer material, containing aliphatic side groups, increased charge carrier mobility in the measured systems. This improvement can be explained by the reduction in the number of the charge carrier trapping sites at the dielectric active layer interface from 1014 eV−1 cm−2 to 2 × 1013 eV−1 cm−2. The density of the traps was one order of magnitude lower compared to the unmodified transistors. This resulted in an increase in charge carrier mobility in the tested poly [2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)] (DPPDTT)-based transistors to 5.4 × 10−1 cm2 V−1 s−1.

scholarly journals Charge transport in disordered organic field-effect transistors

2002 ◽  
Vol 725 ◽  
Author(s):  
Cristina Tanase ◽  
Paul W.M. Blom ◽  
Eduard J. Meijer ◽  
Dago M. de Leeuw
Keyword(s):  
Charge Carrier ◽  
Field Effect ◽  
Carrier Mobility ◽  
Field Effect Transistors ◽  
Charge Carrier Mobility ◽  
Charge Carriers ◽  
Localized States ◽  
Charge Carrier Density ◽  
Organic Field Effect Transistors ◽  
Good Agreement

AbstractThe transport properties of poly(2,5-thienylene vinylene) (PTV) field-effect transistors (FET) have been investigated as a function of temperature under controlled atmosphere. In a disordered semiconductor as PTV the charge carrier mobility, dominated by hopping between localized states, is dependent on the charge carrier density. The transfer characteristics of PTV FET have been modeled considering the distribution of charge carriers and mobility over the accumulation channel. Good agreement with the experimental data is obtained.

scholarly journals Effects of Molecular Structure on Intramolecular Charge Carrier Transport in Dithieno [3,2-b: -d] Pyrrole-Based Conjugated Copolymers

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Yoshihito Honsho ◽  
Akinori Saeki ◽  
Shu Seki
Keyword(s):  
Charge Carrier ◽  
Conjugated Polymer ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Hole Mobility ◽  
Charge Carrier Mobility ◽  
Charge Carriers ◽  
Coupling Reactions ◽  
Time Resolved ◽  
Yamamoto Coupling

Intramolecular mobility of positive charge carriers in conjugated polymer films based on dithieno [2,3-b: -d] pyrrole (DTP) is studied by time-resolved microwave conductivity (TRMC). A series of DTP homopolymer and copolymers combined with phenyl, 2,-biphenyl, thiophene, 2,-bithiophene, and 9,-dioctylfluorene were synthesized by Suzuki-Miyaura and Yamamoto coupling reactions. Polymers containing DTP unit are reported to show high value of hole mobility measured by FET method, and this type of polymers is expected to have stable HOMO orbitals which are important for hole transportation. Among these copolymers, DTP coupled with 9,-dioctylfluorene copolymer showed the highest charge carrier mobility as high as 1.7 cm2/Vs, demonstrating an excellent electrical property on rigid copolymer backbones.

scholarly journals Desarrollo teórico de fotocatalizadores de TiO2 activos en la región visible para la degradación del colorante Anaranjado Ácido 7

2019 ◽  
Author(s):  
◽  
Julio César González Torres
Keyword(s):  
Transition Metals ◽  
Charge Carrier ◽  
Valence Band ◽  
Carrier Mobility ◽  
Density Functional ◽  
Charge Carrier Mobility ◽  
Charge Carriers ◽  
Energy Bands ◽  
Visible Radiation ◽  
Electronic Density

In this work, the physical and chemical properties of the catalyst and reactants involved in the degradation of the acid orange 7 dye are studied to design new photocatalytic materials active and efficient under solar radiation. In the first section, the arguments that have contributed for building the selection criteria of an efficient photocatalyst are presented. These criteria are: a) the proposed materials have to exhibit an oxidation potential similar to the TiO2; b) the photo-generated charge carriers must reach the reactive sites; c) the charge carrier mobility plays an important role in the degradation reaction; d) the energy states generated by the impurities must be located at the energy bands edges; and at last e) the absorbance of visible radiation must be enough to generate the necessary amount of charge carriers to produce the HO● radicals. To tune the optical and electronic properties of the TiO2, based upon these criteria, the doping with two sets of atoms was performed: the main group elements C, N, S, and F and the transition metals Co, Fe, Ni, Pd, and Pt. The calculations were done using the solid state calculations – obtaining the electronic density of states and band structures – and using density functional theory – for the electronic and geometric description of the systems. C-TiO2 and S-TiO2 systems, within the first set, and Pd-TiO2 and Pt-TiO2, within the second, enhance the TiO2 photocatalytic properties. These system generate the least amount of unoccupied states within the energy band gap of the materials – both transition metals generate electronic states in the boundaries of the valence and conduction band and do not reduce the charge carrier mobility. Oxygen vacancies fill the empty states of the dopants and shift them towards to the valence band, “cleaning” the gap and reducing the recombination sites. Finally, the codoping of TiO2 was done using the best candidates of both element sets. The Pt-C-TiO2 codoped system is the most efficient according to the described rules. This codoped material introduces occupied states at the valence band edge, moreover in the (101) surface, the only unoccupied state of the dopant is mixed with the surface unoccupied TiO2 states.

The Influence of Nitrogen Position on Charge Carrier Mobility in Enantiopure Aza[6]helicene Crystals

2018 ◽  
Author(s):  
Francesco Salerno ◽  
Beth Rice ◽  
Julia Schmidt ◽  
Matthew J. Fuchter ◽  
Jenny Nelson ◽  
...  
Keyword(s):  
Solid State ◽  
Charge Carrier ◽  
Carrier Mobility ◽  
Chemical Structure ◽  
Crystal Packing ◽  
Charge Carrier Mobility ◽  
Individual Factor ◽  
Charge Mobility ◽  
Order Of Magnitude ◽  
Small Change

<p>The properties of an organic semiconductor are dependent on both the chemical structure of the molecule involved, and how it is arranged in the solid-state. It is challenging to extract the influence of each individual factor, as small changes in the molecular structure often dramatically change the crystal packing and hence solid-state structure. Here, we use calculations to explore the influence of the nitrogen position on the charge mobility of a chiral organic molecule when the crystal packing is kept constant. The transfer integrals for a series of enantiopure aza[6]helicene crystals sharing the same packing were analysed in order to identify the best supramolecular motifs to promote charge carrier mobility. The regioisomers considered differ only in the positioning of the nitrogen atom in the aromatic scaffold. The simulations showed that even this small change in the chemical structure has a strong effect on the charge transport in the crystal, leading to differences in charge mobility of up to one order of magnitude. Some aza[6]helicene isomers that were packed interlocked with each other showed high HOMO-HOMO integrals (up to 70 meV), whilst molecules arranged with translational symmetry generally afforded the highest LUMO-LUMO integrals (40 - 70 meV). As many of the results are not intuitively obvious, a computational approach provides additional insight into the design of new semiconducting organic materials.</p>

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