The Quinonoid Zwitterion Interlayer for the Improvement of Charge Carrier Mobility in Organic Field-Effect Transistors (original) (raw)
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Advanced Functional Materials, 2015
concept are given by π-extended benzothienobenzothiophene compounds for which hole mobilities up to 17 cm 2 V −1 s −1 in vacuum-processed organic thin fi lm transistor (OTFT) devices could be demonstrated most recently. The second class is based on polymers with alternating donor-acceptor (D-A) units which are commonly used to obtain ambipolar devices. Furthermore, this approach is believed to provide strong electrostatic interactions between D and A segments of neighboring molecules that support charge carrier hopping. Indeed, for many D-A copolymers charge carrier mobilities >1 cm 2 V −1 s −1 have already been achieved, and the highest reported mobilities range at about 10 cm 2 V −1 s −1 . These impressive recent improvements in the fi eld open an exciting potential for organic electronics and should stimulate the elucidation of further molecular π-scaffolds that hitherto have been less explored.
Materials Science in Semiconductor Processing, 2017
In this work, we present a method to increase the performance in solution processed organic field effect transistors (OFET) by using gel as dielectric and molecular doping to the active organic semiconductor. In order to compare the performance improvement, Poly (methylmethacrylate) (PMMA) and Poly (3-hexylthiophene-2,5diyl) P3HT material system were used as a reference. Propylene carbonate (PC) is introduced into PMMA to form the gel for using as gate dielectric. The mobility increases from 5.72×10 −3 to 0.26 cm 2 V s-1 and operation voltage decreases from −60 to −0.8 with gel dielectric. Then, the molecular dopant 2,3,5,6-tetrafluoro-7,7,8,8tetracyanoquinodimethane (F4-TCNQ) is introduced into P3HT via co-solution. The mobility increases up to 1.1 cm 2 V s-1 and the threshold voltage downs to −0.09 V with doping. The increase in performance is discussed in terms of better charge inducing by high dielectric properties of gel and trap filling due to the increased carrier density in active semiconductor by molecular doping.
Gate Insulators in Organic Field-Effect Transistors
Chemistry of Materials - CHEM MATER, 2004
In this paper, we review recent progress in the understanding of insulator/semiconductor interfaces in organic field-effect transistors (OFETs). We would like to emphasize that the choice of gate insulator is as important for high-quality OFET devices as the semiconductor itself, especially because of the unique transport mechanisms operating in them. To date researchers have explored numerous organic and inorganic insulator materials, some of them designed to improve the morphology of the organic semiconductor (OSC). Surface treatments, particularly on inorganic insulators, have been shown to influence significantly molecular ordering and device performance. In addition, the deposition technique used for the insulator and semiconductor layers has a further impact on the active interface. Dielectric related effects are reviewed here for a variety of polymeric and molecular semiconductors reported in the literature, with an emphasis on electronic transport. We also review in more detail experiences at Philips and the recent work at Avecia to clarify some of the interface phenomena using amorphous OSC. Figure 1. Chemical structures of some organic semiconductors discussed in this review.
New Journal of Chemistry, 2018
Here, we design and synthesize three new diketopyrrolopyrrole (DPP) derivatives with naphthalene, possessing large-scaled π-delocalized electronic structure, as the flanking groups and both linear (n-decyl and n-dodecyl) and branched (2-hexyldecyl) alkyl chains as substitutions as active layer for high performance organic field-effect transistors (OFETs). The thermal, photophysical properties, energy levels and solid state molecular stacking have Page 1 of 34 New Journal of Chemistry been studied in detail. All the materials show excellent thermal stability with a decomposition temperature of up to near 400 o C, high semi-crystallinity feature, suitable HOMO & LUMO energy levels, and varying crystalline domain sizes in thin films. Bottom-contact/top-gate transistor devices are thus fabricated to investigate the mobility. Encouragingly, all compounds function well in OFET devices and show significant potential as p-type semiconducting materials. The monomer with the n-decyl alkyl chain (D-DPPN) shows the highest mobility of 0.019 cm 2 V-1 s-1 , with the I on /I off ratio reaching 10 6. We first synthesize naphthalene flanked DPP monomers and achieve high mobility in OFET devices when using these monomers without any further functionalization as semiconductors directly. The primary result that high mobility is observed for monomers only opens a new way for further DPP application and provides more possibilities to constructing high performance polymeric and small molecular semiconductors based on this new DPP dye. frequency identification (RFID) tags. 1-6 As a solution-processing technique, organic semiconducting materials play a significant role in promoting the advances of OFET. 7,8 Consequently, great efforts in materials design have boosted the OFET mobility values achievable from both semiconducting polymers and small molecules up to near 1 cm 2 V-1 s-1. 7-15 Furthermore, several recent papers have reported that mobility values surpassing 10 cm 2 V-1 s-1 can be obtained. 16,17 In spite of the numerous milestone achievements for OFET devices in the last 10 years, it remains a challenge to develop new molecular systems suitable for transistor applications because many synthesized materials did not work or showed very
Journal of Electronic Materials, 2016
Organic field-effect transistors based on poly{[N,N0-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,50-(2,20-bithiophene)}, [P(NDI2OD-T2)n], were fabricated and characterized. The effect of octadecyltrichlorosilane (OTS) a self-assembled monolayer (SAM) grafted on to a SiO 2 gate dielectric was investigated. A significant improvement of the charge mobility (l), up to 0.22 cm 2 /V s, was reached thanks to the OTS treatment. Modifying some technological parameters relating to fabrication, such as solvents, was also studied. We have analyzed the electrical properties of these thin-film transistors by using a two-dimensional drift-diffusion simulator, Integrated System Engineering-Technology Computer Aided Design (ISE-TCAD Ò). We studied the fixed surface charges at the organic semiconductor/ oxide interface and the bulk traps effect. The dependence of the threshold voltage on the density and energy level of the trap states has also been considered. We finally found a good agreement between the output and transfer characteristics for experimental and simulated data.
Chemical Physics Letters, 2018
Diketopyrrolopyrrole (DPP) and i-Indigo (i-Ind) are two monomers that are widely explored as active materials in organic field effect transistor and solar cells. These two molecules showed impressive charge carrier mobility due to better packing that are facilitated by quadrupoles. We hypothesized that the copolymers of these monomers would also exhibit high charge carrier mobility. However, we envisioned that the dihedral angle at the connecting point between the monomers will play a crucial role in packing as well as charge transport. To understand the impact of dihedral angle on charge transport, we synthesized three copolymers, wherein the DPP was sandwiched between benzenes, thiophenes and furans. The copolymer of i-Indigo and furan comprising DPP showed a band gap of 1.4 eV with a very high dihedra. The polymer was found to pack better and the coherence length was found to be 112 Å. The hole carrier mobility of these polymer was found to be highest among the synthesized polymer i.e. 0.01 cm 2 /Vs. The copolymer comprising benzene did not transport hole and electrons. The dihedral angle at the connecting point between i-Indigo and benzene DPP was 143 Å , which the packing and consequently charge transport properties.
Highly Stable Contact Doping in Organic Field Effect Transistors by Dopant‐Blockade Method
Advanced Functional Materials, 2020
In organic device applications, a high contact resistance between metal electrodes and organic semiconductors prevents an efficient charge injection and extraction, which fundamentally limits the device performance. Recently, various contact doping methods have been reported as an effective way to resolve the contact resistance problem. However, the contact doping has not been explored extensively in organic field effect transistors (OFETs) due to dopant diffusion problem, which significantly degrades the device stability by damaging the ON/OFF switching performance. Here, the stability of a contact doping method is improved by incorporating "dopant-blockade molecules" in the poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) film in order to suppress the diffusion of the dopant molecules. By carefully selecting the dopant-blockade molecules for effectively blocking the dopant diffusion paths, the ON/OFF ratio of PBTTT OFETs can be maintained over 2 months. This work will maximize the potential of OFETs by employing the contact doping method as a promising route toward resolving the contact resistance problem.
Advances in Physics: X, 2020
Organic field-effect transistors (OFETs) have been the hotspot in information science for many years as the most fundamental building blocks for state-of-the-art organic electronics. During the field-effect modulation of the semiconducting channel, the gate dielectric always has a significant influence on the charge transport behaviours. Hence, understanding of the nature of charge carriers at the semiconductor/dielectric interface and realizing functional OFETs with superior performance have been the cornerstones for the sustainable advancement in organic electronics. With the joint efforts of predecessors, various basic theories and models have been advanced to describe the charge transport processes in organic crystals. To make a further breakthrough, more accurate correlation between the electrostatic properties of dielectrics and charge carrier behaviours is urgently needed. The high-quality interface-like films, without nonideal factors, two-dimensional molecular crystals (2DMCs), have been spotted as a powerful platform for direct and accurate characterization of the intrinsic charge transport behaviours at the semiconductor/dielectric interface. In this article, the recent breakthroughs in the physics of charge transport, interfacial effects, and perspectives with 2DMCs in OFETs are reviewed, providing great benefits to penetrate the fundamental studies and keep up with the revolutionary advancement in organic-electronics road map.
Organic n-Channel Field-Effect Transistors Based on Arylenediimide-Thiophene Derivatives
Journal of The American Chemical Society, 2010
The synthesis, structural, electrochemical, and thin film electrical and electronic structural properties of a series of arylene diimide-oligothiophene n-type semiconductors are reported. This family of compounds allows analysis of the effects on thin film transistor performance of the following: (i) oligothiophene backbone catenation; (ii) naphthalenediimide vs perylenediimide core interchange; (iii) phenylene group introduction in the oligothiophene backbone. Electrochemical experiments indicate similar redox energetics for all members of this series, while thin film transistor measurements reveal markedly different charge transport performances. The highest electron mobility of 0.35 cm 2 V -1 s -1 is recorded for films of benzo[lmn]thieno[3′,4′:4,5]imidazo[2,1-b][3,8]phenanthroline-1,3,6(2H)-trione, 2-octyl (NDI-1T). Solution-processed field effect transistors were also fabricated and surprisingly exhibit electrical performances surpassing that of the vapor-deposited films in the case of isoquino[6′,5′,4′:10,5,6]anthra [2,1,9def]thieno [3′,4′:4,5]imidazo [2,1-a]isoquinoline-1,3,8(2H)-trione, 2-(1-heptyloctyl)-10,12-di-2-thienyl (PDI-3T). R.; Casado, J.; Hernández, V.; López Navarrete, J. T.; Martinelli, N. G.; Cornil, J.; Sánchez Carrera, R. S.; Coropceanu, V.; Bredas, J. L.