Control of the Mesoscopic Organization of Conjugated Thiophene Oligomers, Induced by Self-Assembly Properties

1993 ◽  
Vol 328 ◽  
Author(s):  
Francis Garnier ◽  
A. Yassar ◽  
R. Hajlaoui ◽  
G. Horowitz ◽  
F. Deloffre
Keyword(s):  
Structural Properties ◽  
Organic Semiconductors ◽  
Self Assembly ◽  
Field Effect Transistors ◽  
Charge Carrier Mobility ◽  
Molecular Engineering ◽  
Molecular Organization ◽  
Conjugated Oligomers ◽  
Planar Molecules ◽  
Mesoscopic Level

ABSTRACTConjugated oligomers form a fascinating class of molecular semiconductors, which open the perspective of control of electronic and structural properties through the variation of their chemical structure. For analysing the correlation between charge transport and structural properties, sexithiophene, 6T, was substituted by hexyl groups, both on the terminal α positions (α,ωDH6T) and as pendant groups in β position (β,β′DH6T). Structural characterizations by X-ray diffraction show that vacuum evaporated thin films of 6T and α,ωDH6T consist of layered structure in a monoclinic arrangement, with all-planar Molecules standing on the substrate, and that a much longer range ordering is observed when passing from 6T to α,ωDH6T, evidencing a large increase of molecular organization at the mesoscopic level. Electrical characterizations also indicate a significant enhancement of anisotropy of conductivity, with a ratio of 120 in favor of the conductivity along the stacking axis for α,ωDH6T. The charge carrier mobility, measured on field-effect transistors fabricated from these conjugated oligomers, also shows a large increase by a factor of 25 when passing from 6T to α,ωDH6T, and reaches a value close to 10-1cm2V-1s-1. In contrast, ββ′DH6T presents very low conductivity and mobility. These observations are attributed to the self-assembly properties brought by alkyl groups in α,ω position, and confirm the large potential of molecular engineering of organic semiconductors.

Soft template assisted self-assembly: a general strategy toward two-dimensional molecular crystals for high-performance organic field-effect transistors

2022 ◽  
Author(s):  
Xinzi Tian ◽  
Jiarong Yao ◽  
Siyu Guo ◽  
Zhaofeng Wang ◽  
Yanling Xiao ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Self Assembly ◽  
High Performance ◽  
Field Effect Transistors ◽  
Molecular Crystals ◽  
Soft Template ◽  
General Strategy ◽  
Two Dimensional ◽  
Organic Field Effect Transistors ◽  
Intrinsic Properties

Two-dimensional molecular crystals (2DMCs) are highly desirable to probe the intrinsic properties in organic semiconductors and are promising candidates for constructing high-performance optoelectronic devices. Liquids such as water are favorable...

scholarly journals Uniform electroactive fibre-like micelle nanowires for organic electronics

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaoyu Li ◽  
Piotr J. Wolanin ◽  
Liam R. MacFarlane ◽  
Robert L. Harniman ◽  
Jieshu Qian ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Charge Carrier ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Field Effect Transistors ◽  
Fibre Length ◽  
Charge Carrier Mobility ◽  
Degree Of Polymerization ◽  
Selective Solvents ◽  
The Individual

Abstract Micelles formed by the self-assembly of block copolymers in selective solvents have attracted widespread attention and have uses in a wide variety of fields, whereas applications based on their electronic properties are virtually unexplored. Herein we describe studies of solution-processable, low-dispersity, electroactive fibre-like micelles of controlled length from π-conjugated diblock copolymers containing a crystalline regioregular poly(3-hexylthiophene) core and a solubilizing, amorphous regiosymmetric poly(3-hexylthiophene) or polystyrene corona. Tunnelling atomic force microscopy measurements demonstrate that the individual fibres exhibit appreciable conductivity. The fibres were subsequently incorporated as the active layer in field-effect transistors. The resulting charge carrier mobility strongly depends on both the degree of polymerization of the core-forming block and the fibre length, and is independent of corona composition. The use of uniform, colloidally stable electroactive fibre-like micelles based on common π-conjugated block copolymers highlights their significant potential to provide fundamental insight into charge carrier processes in devices, and to enable future electronic applications.

Tunneling at Organic/Metal Interfaces in Oligomer-Based Thin-Film Transistors

MRS Bulletin ◽  
1997 ◽  
Vol 22 (6) ◽  
pp. 52-56 ◽  
Author(s):  
Francis Garnier ◽  
Fayçal Kouki ◽  
Rhiad Hajlaoui ◽  
Gilles Horowitz
Keyword(s):  
Charge Transport ◽  
Organic Semiconductors ◽  
Field Effect Transistors ◽  
Substrate Surface ◽  
Three Dimensional ◽  
Amorphous State ◽  
Dimensional Structure ◽  
Conjugated Oligomers ◽  
Large Area ◽  
Strong Luminescence

Organic semiconductors have been studied since the early 1950s, and the large amount of work devoted to them has allowed a better understanding of their charge-transport properties. However owing to their very poor semiconducting characteristics, they were merely considered as exotic materials with little potential interest for applications until the late 1980s, when two significant steps simultaneously appeared in the literature. Richard Friend's group showed that light-emitting diodes could be made from a conjugated semiconducting polymer, and our laboratory showed that efficient field-effect transistors (FETs) could be realized from short-conjugated oligomers. These two results launched intensive research on these two types of organic-based devices, and the extensive work accomplished since has largely confirmed the technological pertinence of organic semiconductors, showing the promise for applications in flexible and large-area electronics. Two categories of organic semiconductors are actually under development: (1) conjugated polymer-based ones whose amorphous state is favorable to strong luminescence and (2) conjugated oligomer-based ones, in which charge-transport efficiency is directly related to the long-range packing of molecules in the semiconducting film. In fact conjugated oligomers can be said to be forming molecular polycrystals whose electrical properties are essentially controlled by molecular order. Thus performance of sexithiophene-based FETs has been improved by a factor of nearly 50 by controlling the molecular ordering in the evaporated film, from a disordered three-dimensional structure to a well-ordered two-dimensional organization where all the molecules stack along a packing axis nearly parallel to the substrate surface.

scholarly journals Hydrogen-Bonded Conjugated Materials and Their Application in Organic Field-Effect Transistors

2021 ◽  
Vol 9 ◽  
Author(s):  
Xin Shi ◽  
Weiwei Bao
Keyword(s):  
Organic Semiconductors ◽  
Self Assembly ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Organic Field Effect Transistors ◽  
Conjugated Materials ◽  
Chemical Structures ◽  
Simple Strategy ◽  
Stacking Order ◽  
Hydrogen Bonded

Recent research on organic semiconductors has revealed that the composition of the constituent organic material, as well as the subtle changes in its structure (the stacking order of molecules), can noticeably affect its bulk properties. One of the reasons for this is that the charge transport in conjugated materials is strongly affected by their structure. Further, the charge mobility increases significantly when the conjugated materials exhibit self-assembly, resulting in the formation of ordered structures. However, well-organized nanostructures are difficult to obtain using classical solution processing methods, owing to their disordered state. A simple strategy for obtaining well-ordered material films involves synthesizing new conjugated materials that can self-organize. Introducing hydrogen bonding in the materials to yield hydrogen-bonded material superstructures can be a suitable method to fulfill these critical requirements. The formed hydrogen bonds will facilitate the assembly of the molecules into a highly ordered structure and bridge the distance between the adjacent molecules, thus enhancing the intermolecular charge transfer. In this minireview, hydrogen-bonded small molecules and polymers as well as the relationship between their chemical structures and performances in organic field-effect transistors are discussed.

scholarly journals Controlled Self-Assembly of Conjugated Polymers via a Solvent Vapor Pre-Treatment for Use in Organic Field-Effect Transistors

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 332 ◽  
Author(s):  
Gyounglyul Jo ◽  
Jaehan Jung ◽  
Mincheol Chang
Keyword(s):  
Conjugated Polymers ◽  
Self Assembly ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Grazing Incidence ◽  
Charge Carrier Mobility ◽  
Molecular Assembly ◽  
Solvent Vapor ◽  
Precise Control ◽  
Vis Spectroscopy

A facile solution-processing strategy toward well-ordered one-dimensional nanostructures of conjugated polymers via a non-solvent vapor treatment was demonstrated, which resulted in enhancements to the charge transport characteristics of the polymers. The amount of crystalline poly(3-hexylthiophene) (P3HT) nanofibers was precisely controlled by simply varying the exposure time of solutions of P3HT solutions to non-solvent vapor. The effects of non-solvent vapor exposure on the molecular ordering and morphologies of the resultant P3HT films were systematically investigated using ultraviolet-visible (UV-vis) spectroscopy, polarized optical microscopy (POM), grazing incidence X-ray diffraction (GIXRD), and atomic force microscopy (AFM). The non-solvent vapor facilitates the π–π stacking in P3HT to minimize unfavorable interactions between the poor solvent molecules and P3HT chains. P3HT films deposited from the non-solvent vapor-treated P3HT solutions exhibited an approximately 5.6-fold improvement in charge carrier mobility as compared to that of pristine P3HT films (7.8 × 10−2 cm2 V−1 s−1 vs. 1.4 × 10−2 cm2 V−1 s−1). The robust and facile strategy presented herein would be applicable in various opto-electronics applications requiring precise control of the molecular assembly, such as organic photovoltaic cells, field-effect transistors, light-emitting diodes, and sensors.

The Influence of Diketopyrrolopyrrole Chemical Structure on Organic Field-Effect Transistors Performance

2016 ◽  
Vol 851 ◽  
pp. 189-193
Author(s):  
Stanislav Stříteský ◽  
Jozef Krajčovič ◽  
Martin Vala ◽  
Martin Weiter
Keyword(s):  
Organic Semiconductors ◽  
Field Effect ◽  
Soluble Group ◽  
Gate Dielectrics ◽  
Field Effect Transistors ◽  
Charge Trapping ◽  
Charge Carrier Mobility ◽  
Self Assembled Monolayers ◽  
Organic Field Effect Transistors ◽  
Assembled Monolayers

Organic semiconductors are suitable for application in biosensors and sensors based on transistors. The influence of soluble group modifications on the performance of diketopyrrolopyrrole-based organic field-effect transistors (OFETs) is studied. The lowest mobility 1·10-9 cm2/Vs was observed for non-symmetric substitution O,N. Measurable charge carrier mobility was observed due to reduction of the density charge trapping states after application of organosilane self-assembled monolayers (SAMs) on thinner gate-dielectrics (90 nm). We report similar drift mobility 1·10-7 cm2/Vs for smallest soluble group “butyl” as for biggest group “EthylAdamantyl” in N,N and O,O substitution prepared by spin-coating.

scholarly journals Molecular engineering of polymersome surface topology

2016 ◽  
Vol 2 (4) ◽  
pp. e1500948 ◽  
Author(s):  
Lorena Ruiz-Pérez ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
Adrian Joseph ◽  
Ludovico Sutto ◽  
...  
Keyword(s):  
Interfacial Tension ◽  
Chemical Synthesis ◽  
Self Assembly ◽  
Chemical Nature ◽  
Molecular Engineering ◽  
Surface Topology ◽  
Complex Structures ◽  
Amphiphilic Copolymers ◽  
Membrane Formation ◽  
Mesoscopic Level

Biological systems exploit self-assembly to create complex structures whose arrangements are finely controlled from the molecular to mesoscopic level. We report an example of using fully synthetic systems that mimic two levels of self-assembly. We show the formation of vesicles using amphiphilic copolymers whose chemical nature is chosen to control both membrane formation and membrane-confined interactions. We report polymersomes with patterns that emerge by engineering interfacial tension within the polymersome surface. This allows the formation of domains whose topology is tailored by chemical synthesis, paving the avenue to complex supramolecular designs functionally similar to those found in viruses and trafficking vesicles.

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