scholarly journals Carbonyl-Terminated Quinoidal Oligothiophenes as p-Type Organic Semiconductors

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3020
Author(s):  
Takato Asoh ◽  
Kohsuke Kawabata ◽  
Kazuo Takimiya
Keyword(s):  
Organic Semiconductors ◽  
Field Effect Transistors ◽  
Theoretical Calculations ◽  
Energy Levels ◽  
Hole Mobility ◽  
Hole Transport ◽  
Large Contribution ◽  
Theoretical Predictions ◽  
Reorganization Energies ◽  
P Type

A series of quinoidal oligothiophenes terminated with carbonyl groups (nTDs, n = 2–4) are studied as p-type organic semiconductors for the active materials in organic field-effect transistors (OFETs) both by the theoretical and experimental approaches. The theoretical calculations clearly show their high-lying highest occupied molecular orbital (HOMO) energy levels (EHOMOs), small reorganization energies for hole transport (λholes), and large contribution of sulfur atoms to HOMOs, all of which are desirable for p-type organic semiconductors. Thus, we synthesized nTDs from the corresponding aromatic oligothiophene precursors and then evaluated their physicochemical properties and structural properties. These experimental evaluations of nTDs nicely proved the theoretical predictions, and the largest 4TDs in the series (4,4′′′-dihexyl- and 3′,4,4″,4′′′-tetrahexyl-5H,5′′′H-[2,2′:5′,2″:5″,2′′′-quaterthiophene]-5,5′′′-dione) can afford solution-processed OFETs showing unipolar p-type behaviors and hole mobility as high as 0.026 cm2 V−1 s−1.

Theoretical Approach for the Development of Organic Semiconductors on the Basis of the MO Symmetry: Thienoacene as an Example

2012 ◽  
Vol 1436 ◽  
Author(s):  
Hirotaka Kojima ◽  
Takehiko Mori
Keyword(s):  
Organic Semiconductors ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Theoretical Calculations ◽  
Energy Levels ◽  
Two Dimensional ◽  
Organic Field Effect Transistors ◽  
Transfer Integrals ◽  
Reorganization Energies ◽  
Herringbone Structure

ABSTRACTWe have explored materials for organic field-effect transistors (OFETs) from the viewpoint of theoretical calculations. The herringbone structure, which realizes two-dimensional conduction, is investigated in detail. Transfer integrals (t) are calculated systematically as a function of the dihedral angle between the molecular planes (θ) and the displacement along the molecular long axis (D). Acenes, oligothiophenes, thienoacenes and tetrathiafulvalenes are investigated, and are discussed from the molecular orbital (MO) symmetry. Thienoacenes (nTAs) are particularly examined as a candidate of OFET materials from the calculations of transfer integrals and reorganization energies (λ) based on the energy levels and the MO symmetry. LUMO of nTAs have MO symmetry suitable for conduction, but these orbitals are usually not related to the conduction. We have investigated the electronic properties of the derivatives with dicarboximide moiety. nTA-tetracarboxydiimide is expected to show the herringbone structure and exhibit n-type transport from the properties of LUMO.

scholarly journals Progress on the Synthesis and Application of CuSCN Inorganic Hole Transport Material in Perovskite Solar Cells

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2592 ◽  
Author(s):  
Funeka Matebese ◽  
Raymond Taziwa ◽  
Dorcas Mutukwa
Keyword(s):  
Solar Cells ◽  
Energy Levels ◽  
Perovskite Solar Cells ◽  
Hole Mobility ◽  
Cost Effective ◽  
Vital Role ◽  
Hole Transport ◽  
Recombination Processes ◽  
Short Synthesis ◽  
P Type

P-type wide bandgap semiconductor materials such as CuI, NiO, Cu2O and CuSCN are currently undergoing intense research as viable alternative hole transport materials (HTMs) to the spiro-OMeTAD in perovskite solar cells (PSCs). Despite 23.3% efficiency of PSCs, there are still a number of issues in addition to the toxicology of Pb such as instability and high-cost of the current HTM that needs to be urgently addressed. To that end, copper thiocyanate (CuSCN) HTMs in addition to robustness have high stability, high hole mobility, and suitable energy levels as compared to spiro-OMeTAD HTM. CuSCN HTM layer use affordable materials, require short synthesis routes, require simple synthetic techniques such as spin-coating and doctor-blading, thus offer a viable way of developing cost-effective PSCs. HTMs play a vital role in PSCs as they can enhance the performance of a device by reducing charge recombination processes. In this review paper, we report on the current progress of CuSCN HTMs that have been reported to date in PSCs. CuSCN HTMs have shown enhanced stability when exposed to weather elements as the solar devices retained their initial efficiency by a greater percentage. The efficiency reported to date is greater than 20% and has a potential of increasing, as well as maintaining thermal stability.

scholarly journals 2,2'-(Arylenedivinylene)bis-8-hydroxyquinolines exhibiting aromatic π-π stacking interactions as solution-processable p-type organic semiconductors for high-performance organic field effect transistors

2021 ◽  
Author(s):  
Suman Yadav ◽  
Shivani Sharma ◽  
Satinder K Sharma ◽  
Chullikkattil P. Pradeep
Keyword(s):  
Organic Semiconductors ◽  
Field Effect ◽  
High Performance ◽  
Field Effect Transistor ◽  
Field Effect Transistors ◽  
Organic Field Effect Transistors ◽  
Organic Thin Film ◽  
Effect Transistor ◽  
Solution Processable ◽  
P Type

Solution-processable organic semiconductors capable of functioning at low operating voltages (~5 V) are in demand for organic field-effect transistor (OFET) applications. Exploration of new classes of compounds as organic thin-film...

scholarly journals Светоизлучающие полевые транзисторы на основе композитных пленок полифлуорена и нанокристаллов CsPbBr-=SUB=-3-=/SUB=-

2019 ◽  
Vol 61 (2) ◽  
pp. 388
Author(s):  
А.Н. Алешин ◽  
И.П. Щербаков ◽  
Д.А. Кириленко ◽  
Л.Б. Матюшкин ◽  
В.А. Мошников
Keyword(s):  
Field Effect Transistors ◽  
Composite Films ◽  
Hole Mobility ◽  
Hole Transport ◽  
Component Ratio ◽  
Organic Field Effect Transistors ◽  
Electrical And Optical Properties ◽  
Light Emitting ◽  
Current Voltage ◽  
Current Voltage Characteristics

Abstract—Light-emitting organic field-effect transistors (LE-FETs) on the basis of composite films that consist of perovskite nanocrystals (CsPbBr_3) embedded in a matrix of conjugated polymer—polyfluorene (PFO)—have been obtained, and their electrical and optical properties have been investigated. Output and transfer current-voltage characteristics (I-Vs) of FETs based on PFO : CsPbBr_3 films (component ratio 1 : 1) have a slight hysteresis at temperatures of 100–300 K and are characteristic of hole transport. The hole mobility is ∼3.3 and ∼1.9 cm^2/(V s) at the modes of the saturation and low fields, respectively, at 250 K and reaches ∼5 cm^2/(V s) at 100 K. It has been shown that the application of pulsed voltage to LE-FETs based on PFO : CsPbBr_3 can reduce the ionic conductivity and provide electroluminescence in this structure at 300 K.

Donor-acceptor copolymers and sol-gel processable zinc oxide for thin film transistors and hybrid photodetectors

2019 ◽  
Author(s):  
◽  
Alec Pickett
Keyword(s):  
Organic Semiconductors ◽  
Field Effect Transistors ◽  
Sol Gel ◽  
Phenyl Group ◽  
Grazing Incidence ◽  
Second Phase ◽  
Commercial Development ◽  
University Of Missouri ◽  
Pi Conjugated ◽  
P Type

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Organic semiconductors have been gaining attention both in research and commercial development for electronic devices due to their low manufacturing and processing costs. Copolymers based on diketopyrrolopyrrole (DPP) cores have attracted a lot of attention due to their high p-type as well as n-type carrier mobilities in organic field-effect transistors (FETs) and high power conversion efficiencies in solar cell structures. Hybrid organic-inorganic photodiode interfaces have also gained significant interest due to the realization of intrinsic p-n junctions as well as their unique physical properties such as mechanical flexibility and high photosensitivity. ZnO is an intrinsic n-type semiconductor which is non-toxic and sol-gel processable, creating avenues for film patterning and fully solution processed devices. In this work, we report the structural and charge transport properties of n-dialkyl side-chain substituted thiophene DPP end-capped with a phenyl group (Ph-TDPP-Ph) monomer in FETs which were fabricated by vacuum deposition and solvent casting. From grazing incidence X-ray diffraction (GIXRD), Ph-TDPP-Ph reveals polymorphic structure with [pi]-conjugated stacking direction oriented in-plane. The unit cell comprises either one monomer for one phase (TR1), or two monomers for the second phase (TR2). The TR2 phase thus signals a shift from a coplanar to herringbone orientation of the molecules. The device performance is sensitive to the ratio of the two triclinic phases found in the film. Some of the best FET performances with p-type carrier mobilities of 0.1 cm2/Vs and on/off ratio of 10[superscript 6] are for films that comprise mainly the TR1 phase.

scholarly journals Diamond Based Field-Effect Transistors of Zr Gate withSiNxDielectric Layers

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
W. Wang ◽  
C. Hu ◽  
S. Y. Li ◽  
F. N. Li ◽  
Z. C. Liu ◽  
...  
Keyword(s):  
Carrier Density ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Field Effect Transistors ◽  
Hole Mobility ◽  
Conduction Channel ◽  
Effect Transistor ◽  
P Type ◽  
Interface Bond ◽  
Transfer Properties

Investigation of Zr-gate diamond field-effect transistor withSiNxdielectric layers (SD-FET) has been carried out. SD-FET works in normally on depletion mode with p-type channel, whose sheet carrier density and hole mobility are evaluated to be 2.17 × 1013 cm−2and 24.4 cm2·V−1·s−1, respectively. The output and transfer properties indicate the preservation of conduction channel because of theSiNxdielectric layer, which may be explained by the interface bond of C-N. High voltage up to −200 V is applied to the device, and no breakdown is observed. For comparison, another traditional surface channel FET (SC-FET) is also fabricated.

Theoretical Investigation of Structural Effects on the Charge Transfer Properties in Modified Phthalocyanines

MRS Advances ◽  
2015 ◽  
Vol 1 (7) ◽  
pp. 453-458 ◽  
Author(s):  
Patrick J. Dwyer ◽  
Stephen P. Kelty
Keyword(s):  
Organic Semiconductors ◽  
Electron Affinity ◽  
Density Functional ◽  
Reorganization Energy ◽  
High Electron ◽  
Optoelectronic Materials ◽  
Research Attention ◽  
Efficient Charge ◽  
Reorganization Energies ◽  
P Type

ABSTRACTFor efficient charge separation and charge transport in optoelectronic materials, small internal reorganization energies are desired. While many p-type organic semiconductors have been reported with low internal reorganization energies, few n-type materials with low reorganization energy are known. Metal phthalocyanines have long received extensive research attention in the field of organic device electronics due to their highly tunable electronic properties through modification of the molecular periphery. In this study, density functional theory (DFT) calculations are performed on a series of zinc-phthalocyanines (ZnPc) with various degrees of peripheral per-fluoroalkyl (-C3F7) modification. Introduction of the highly electron withdrawing groups on the periphery leads to a lowering in the energy of the molecular frontier orbitals as well as an increase in the electron affinity. Additionally, all molecules studies are found to be most stable in their anionic form, demonstrating their potential as n-type materials. However, the calculated internal reorganization energy slightly increases as a function of peripheral modification. By varying the degree of modification we develop a strategy for obtaining an optimal balance between low reorganization energy and high electron affinity for the development of novel n-type optoelectronic materials.

scholarly journals Dynamic Infrared Electro-optic Response of Soluble Organic Semiconductors in Thin Film Transistors

2013 ◽  
Vol 1501 ◽  
Author(s):  
Emily G. Bittle ◽  
Joseph W. Brill ◽  
Joseph P. Straley
Keyword(s):  
Organic Semiconductors ◽  
Field Effect Transistors ◽  
Metal Layer ◽  
Hole Mobility ◽  
Atomic Layer ◽  
Semiconductor Films ◽  
Contact Impedance ◽  
Low Frequencies ◽  
Electro Optic ◽  
Linear Differential

ABSTRACTWe use a frequency-dependent electro-optic technique to measure the hole mobility in small molecule organic semiconductors, such as 6,13 bis(triisopropylsilylethynyl)-pentacene. Measurements are made on semiconductor films in bottom gate, bottom contact field-effect transistors (FETs.) Because of the buried metal layer effect the maximum response, due to absorption in the charge layer, will be for a dielectric film ∼ 1/4 of a wavelength (in the dielectric) (e.g. ∼ 1 micron thick in the infrared.) Results are presented for FETs prepared with both spin-cast polymer and alumina dielectrics prepared by atomic layer deposition. At low frequencies the results are fit to solutions to a non-linear differential equation describing the spatial dependence of flowing charge in the FET channel, which allows us to study multiple crystals forming across one set of drain-source contacts. FETs prepared on alumina dielectrics show interesting deviations from the model at high frequencies, possibly due to increased contact impedance.

Hole mobility enhancements in strained Si/Si1−yGey p-type metal-oxide-semiconductor field-effect transistors grown on relaxed Si1−xGex (x

2001 ◽  
Vol 79 (25) ◽  
pp. 4246-4248 ◽  
Author(s):  
C. W. Leitz ◽  
M. T. Currie ◽  
M. L. Lee ◽  
Z.-Y. Cheng ◽  
D. A. Antoniadis ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Hole Mobility ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Strained Si ◽  
P Type

Naphtho[2,1-b:3,4-b′]bisthieno[3,2-b][1]benzothiophene-based semiconductors for organic field-effect transistors

2015 ◽  
Vol 3 (31) ◽  
pp. 8024-8029 ◽  
Author(s):  
Zhaoguang Li ◽  
Ji Zhang ◽  
Kai Zhang ◽  
Weifeng Zhang ◽  
Lei Guo ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Field Effect ◽  
High Performance ◽  
Field Effect Transistors ◽  
Hole Mobility ◽  
Building Blocks ◽  
Organic Field Effect Transistors ◽  
Next Generation

Naphtho[2,1-b:3,4-b′]bisthieno[3,2-b][1]benzothiophene derivatives exhibiting a hole mobility of up to 0.25 cm2 V−1 s−1 show promise as useful building blocks to construct next-generation high performance organic semiconductors.

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