scholarly journals Raman investigation of electric field induced molecular modifications in organic field effect transistors

ELEMENTOS ◽  
2013 ◽  
Vol 2 (2) ◽  
Author(s):  
Beynor Antonio Paez Sierra ◽  
Fredy Giovanni Mesa Rodríguez
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Field Effect ◽  
Density Functional ◽  
Field Effect Transistors ◽  
Dipole Interaction ◽  
Original Structure ◽  
Organic Layer ◽  
Organic Field Effect Transistors ◽  
Functional Theory

The influence of external electric fields on the vibrational properties of Pentacene-based field effect transistors were investigated by Ramanspectroscopy.ThemonitoredRamanbandswereintherangefrom 1100cm−1 to1200cm−1,whereabroadbandispresentandenhanceddue to the external electric field. The process is modeled by density functional theory (DFT) at the B3LYP/3–21G level. Additionally, the relaxation of the Raman bands after the removal of the external field was determined from an exponential Debye like decay fitting to be approximately 94 min, this finding indicates that a long relaxation time ca. 8 h is required in order to recover the original structure. Experimentally and theoretically was demonstrated that the applied electric fields induce artificial traps in the organic layer mediated by charge carrier–dipole interaction.

Organic Field-Effect Transistors Based on 3’-Flouro-2,2',6,6'-Tetraphenyl-4,4'-Dipyranylidene

2019 ◽  
Vol 288 ◽  
pp. 37-43
Author(s):  
Altan Bolag ◽  
Yoshiro Yamashita
Keyword(s):  
Field Effect ◽  
Density Functional ◽  
Field Effect Transistors ◽  
Organic Field Effect Transistors ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
Visible Spectroscopy ◽  
Functional Theory ◽  
X Ray ◽  
Contact Configuration

In this work, 3’-flouro-2,2',6,6'-tetraphenyl-4,4'-dipyranylidene (3FDP) was originally synthesized and investigated with density functional theory (DFT) calculations, ultraviolet–visible spectroscopy (UV–Vis) and cyclic voltammetry (CV) in comparison with 2,2',6,6'-tetraphenyl-4,4'-dipyranylidene (DP) and 4’-flouro-2,2',6,6'-tetraphenyl-4,4'-dipyranylidene (4FDP). 3FDP-based organic field-effect transistors (OFETs) were fabricated with bottom contact configuration on bare SiO2/Si substrate, 1,1,1,3,3,3-hexamethyldisilazane (HMDS) and octadecyltrichlorosilane (OTS) treated substrate, respectively. The HMDS-treated device showed highest mobility of 4 × 10−4 cm2 V−1 s−1, on/off ratio of 4 × 103 and threshold voltage of −10 V. Finally, vacuum deposited 3FDP films morphology was investigated by X-ray diffraction (XRD) analyses and the results showed higher crystallinity of HMDS-treated 3FDP film compared to the OTS-treated film, leading to a better FET performance.

scholarly journals Fluorene-Based Donor-Acceptor Copolymers Containing Functionalized Benzotriazole Units: Tunable Emission and their Electrical Properties

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 256 ◽  
Author(s):  
Iván Torres-Moya ◽  
Rebeca Vázquez-Guilló ◽  
Sara Fernández-Palacios ◽  
José Ramón Carrillo ◽  
Ángel Díaz-Ortiz ◽  
...  
Keyword(s):  
Density Functional ◽  
Field Effect Transistors ◽  
Photophysical Properties ◽  
Suzuki Reaction ◽  
Organic Field Effect Transistors ◽  
Functional Theory ◽  
Organic Optoelectronics ◽  
Donor Acceptor ◽  
Chain Lengths ◽  
Tunable Emission

Monomers 4,7-dibromo-2H-benzo[d]1,2,3-triazole (m1) and 4,7-(bis(4-bromophenyl)ethynyl)-2H-benzo[d]1,2,3-triazole (m2) have been synthesized in good yields using different procedures. Monomers m1 and m2 have been employed for building new copolymers of fluorene derivatives by a Suzuki reaction under microwave irradiation using the same conditions. In each case different chain lengths have been achieved, while m1 gives rise to polymers for m2 oligomers have been obtained (with a number of monomer units lower than 7). Special interest has been paid to their photophysical properties due to excited state properties of these D-A units alternates, which have been investigated by density functional theory (DFT) calculations using two methods: (i) An oligomer approach and (ii) by periodic boundary conditions (PBC). It is highly remarkable the tunability of the photophysical properties as a function of the different monomer functionalization derived from 2H-benzo[d]1,2,3-triazole units. In fact, a strong modulation of the absorption and emission properties have been found by functionalizing the nitrogen N-2 of the benzotriazole units or by elongation of the π-conjugated core with the introduction of alkynylphenyl groups. Furthermore, the charge transport properties of these newly synthesized macromolecules have been approached by their implementation in organic field-effect transistors (OFETs) in order to assess their potential as active materials in organic optoelectronics.

Molecular Electronics Including Temperature Effects Based on Dyes Pigments

2019 ◽  
Vol 19 (6) ◽  
pp. 3631-3636
Author(s):  
Adriana T Amador ◽  
Abel F. G Neto ◽  
Jorddy N Cruz ◽  
Fatima N. B Magno ◽  
Francisco C Marques ◽  
...  
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Molecular Electronics ◽  
Electric Fields ◽  
Density Functional ◽  
Functional Theory ◽  
Degradation Temperature ◽  
Red Color ◽  
The Density Functional Theory ◽  
Almost All

In this work we used the Density Functional Theory to study the thermodynamic properties from Brazilein (BZE) and Brazilin (BZI) molecules, main pigments responsible for the red color from Brazil wood. We did a comparison between the two dyes to then know which dye has better resistance to temperature (T ) and external electric field (E) values, aiming their potential to possible applications in solar cells, as excitons trainers. We have found that the BZE molecule becomes less stable after a temperature known as degradation temperature, and therefore enters oxidation state. However, BZE is more stable and more resistant to high temperatures. With respect to the applied external electric field, we find that BZE is more reactive to almost all the applied electric fields, thus more easily converted into energy in the form of electrical work.

ATOMISTIC SIMULATION OF GATE EFFECT ON NANOSCALE INTRINSIC Si FIELD-EFFECT TRANSISTORS

2009 ◽  
Vol 08 (01n02) ◽  
pp. 113-117 ◽  
Author(s):  
X. F. WANG ◽  
L. N. ZHAO ◽  
Z. H. YAO ◽  
Z. F. HOU ◽  
M. YEE ◽  
...  
Keyword(s):  
Field Effect ◽  
Density Functional ◽  
Field Effect Transistors ◽  
Functional Theory ◽  
Poisson Solver ◽  
System A ◽  
Voltage Curve ◽  
Gate Effect ◽  
Multigrid Poisson Solver ◽  
Model Device

We study the electrostatic and quantum transport properties of nanoscale double-gated Si -based field effect transistors within the framework of density functional theory combined with nonequilibrium Green's function approach. In our model device system, a Si slab is sandwiched between two insulator slabs and connected to two semi-infinite Si electrodes at its left and right ends. The effect of the double gates is taken into account by applying proper electrostatic boundary conditions and solving the Poisson equation self-consistently in the system. In the representation of localized SIESTA linear combination of atomic orbitals, the study is carried out with the help of Atomistix ToolKit (ATK) package together with an efficient multigrid Poisson solver. We find that the surface potential versus gate voltage curve shows similar characteristics as in conventional MOSFETs even for devices of 1 nm size, though the shape of the curve varies with the shrink of the system. In different working regimes of the devices, the electrostatic potential and the transmission spectrum are analyzed for an atomistic understanding of the device behavior.

Direct imaging of electric field behavior in 2,7-diphenyl[1]benzothieno[3,2-b][1]benzothiophene organic field-effect transistors by sum-frequency generation imaging microscopy

2021 ◽  
Author(s):  
Chiho Katagiri ◽  
Takayuki Miyamae ◽  
Hao Li ◽  
Fangyuan Yang ◽  
Steven Baldelli
Keyword(s):  
Electric Field ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Sum Frequency Generation ◽  
Internal Electric Field ◽  
Organic Field Effect Transistors ◽  
Direct Imaging ◽  
Sum Frequency ◽  
Field Behavior ◽  
Frequency Generation

Sum frequency generation imaging microscopy was applied to visualize the internal electric-field behavior in operating organic field effect transistors.

Enhanced Mobility of Organic Field-Effect Transistors with Epitaxially Grown C60 Film by in-situ Heat Treatment of the Organic Dielectric

2005 ◽  
Vol 871 ◽  
Author(s):  
Th. B. Singh ◽  
N. Marjanovic ◽  
G. J. Matt ◽  
S. Günes ◽  
N. S. Sariciftci ◽  
...  
Keyword(s):  
Thin Film ◽  
Electric Fields ◽  
Field Effect ◽  
Film Growth ◽  
Field Effect Transistors ◽  
Growth Conditions ◽  
Initial Growth ◽  
Organic Field Effect Transistors ◽  
Enhanced Mobility ◽  
High Electric Fields

AbstractElectron mobilities were studied as a function of thin-film growth conditions in hot wall epitaxially grown C60 based field-effect transistors. Mobilities in the range of ∼ 0.5 to 6 cm2/Vs are obtained depending on the thin-film morphology arising from the initial growth conditions. Moreover, the field-effect transistor current is determined by the morphology of the film at the interface with the dielectric, while the upper layers are less relevant to the transport. At high electric fields, a non-linear transport has been observed. This effect is assigned to be either because of the dominance of the contact resistance over the channel resistance or because of the gradual move of the Fermi level towards the band edge as more and more empty traps are filled due to charge injection.

Origin of electric field response signals in gate modulation spectroscopy for organic field effect transistors

2020 ◽  
Vol 87 ◽  
pp. 105934
Author(s):  
Katsuichi Kanemoto ◽  
Ayato Iida ◽  
Kazunori Iwamitsu ◽  
Kyohei Higashiyama ◽  
Hiroyuki Kumazoe ◽  
...  
Keyword(s):  
Electric Field ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Organic Field Effect Transistors ◽  
Modulation Spectroscopy ◽  
Field Response
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