Soliton And Bipolaron Excitations In Conjugated Polymers Of Different Conjugation Length

1992 ◽  
Author(s):  
Dellepiane ◽  
Lanzani ◽  
Cuniberti ◽  
Tubino
Keyword(s):  
Conjugated Polymers ◽  
Conjugation Length

scholarly journals Highly Conductive and Soluble Polymer Synthesized by Copolymerization of Thiophene with Para-Methoxybenzaldehyde Using Clay Catalyst

2019 ◽  
Vol 14 (2) ◽  
pp. 413 ◽  
Author(s):  
Djamal Eddine Kherroub ◽  
Larbi Bouhadjar ◽  
Bouhadjar Boukoussa ◽  
Abdelkader Rahmouni ◽  
Khadidja Dahmani ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Conducting Polymer ◽  
Model System ◽  
Proton Nuclear Magnetic Resonance ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Conjugation Length ◽  
Visible Spectroscopy ◽  
A Value ◽  
Clay Catalyst

This present research focuses on the synthesis of a new conducting polymer based on the copolymerization of thiophene with para-methoxybenzaldehyde, using a clay as an ecologic catalyst named Maghnite-H+. The catalysis of the reaction by Maghnite-H+ can confer it important benefits, such as the green environment aspect. The reaction was carried out in dichloromethane as a solvent. The new copolymer obtained is a poly (heteroarylene methines) small bandgap polymers precursor. It can be considered as a useful model system for examining the impacts of π-conjugation length on the electronic properties of this type of conjugated polymers. The measurements of the electrical conductivity gave a value of order of 0.0120 W.cm-1, allowing its use in various important applications. The characteristics of the molecular structure and the thermal behavior of the conducting polymer obtained are also discussed using different methods of analysis, such as: proton nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopy, ultraviolet/visible spectroscopy, and thermal gravimetric analysis (TGA). Copyright © 2019 BCREC Group. All rights reserved 

Synthesis and Optical Properties of a Novel Oligobipyridine

2001 ◽  
Vol 665 ◽  
Author(s):  
Y. J. Fu ◽  
T.K.S. Wong ◽  
H.X. Zhang ◽  
G. M. Wang ◽  
X. Hu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Conjugated Polymers ◽  
Double Layer ◽  
Single Layer ◽  
Emission Spectra ◽  
Amorphous Film ◽  
Emission Peak ◽  
Conjugation Length ◽  
Emission Color ◽  
Film State

ABSTRACTIn this paper, 5,5' –bis [ 4'– methyl- ( 2,2'– bipyridin– 4- yl)- ethyl ]- 2,2'– bipyridine (BMBPYBPY), a partially conjugated derivative of oligobipyridine, has been synthesized and found to show strong photoluminescence (PL). Compared with the pyridine-based conjugated polymers, the shortened conjugation length shifts the emission color from green to violet-blue. The effects of morphology on its PL properties have been studied. From its as-precipitated powder state, an emission peak at 418 nm can be observed. However the emission spectra from its diffused states such as doped in KBr, or dissolved in CHCl3, as well as from its amorphous film state fabricated by vacuum evaporation are more complex. Also carried out are preliminary electroluminescent studies. Single layer devices ITO/BMBPYBPY/Al do not emit although current can be observed prominently. Double layer devices ITO/TPD/ BMBPYBPY/Al show emissions both from TPD and BMBPYBPY.

Electronic properties of conjugated polymers

1985 ◽  
Vol 314 (1528) ◽  
pp. 37-49 ◽  
Keyword(s):  
Optical Absorption ◽  
Conjugated Polymers ◽  
Defect State ◽  
Chemical Doping ◽  
Conjugation Length ◽  
Defect States ◽  
Physical Measurements ◽  
Wide Range ◽  
Precursor Route ◽  
Absorption Features

The nature of the proposed defect states in conjugated polymers (solitons and polarons in polyacetylene, polarons and bipolarons in other materials) is expected to be strongly dependent on the morphology and chain conjugation length of the polymer. Polyacetylene prepared by the Durham ‘precursor’ route has a lower conjugation length than that prepared by the Shirakawa route, and it is expected that polarons or bipolarons rather than solitons should be the defect state introduced during chemical doping. We discuss here a wide range of physical measurements made on Durham polyacetylene. We present data for two other, processible, polymers. Poly(phenylenesulphide) shows strong optical absorption features below the band gap when reversibly doped with AsF 5 . Poly(diphenylenediphenylvinylene) shows similar behaviour and evidence for photogeneration and chemical generation of polaron-like states in this material is presented.

Assessing the Effects of Increasing Conjugation Length on Exciton Diffusion: From Small Molecules to the Polymeric Limit

2021 ◽  
Author(s):  
Leonardo E de Sousa ◽  
Laura Simonassi Raso de Paiva ◽  
DEMETRIO DA SILVA FILHO ◽  
Gjergji Sini ◽  
Pedro Henrique Neto
Keyword(s):  
Solar Cells ◽  
Conjugated Polymers ◽  
Small Molecules ◽  
Small Molecule ◽  
Organic Solar Cells ◽  
Conjugation Length ◽  
Exciton Diffusion ◽  
Pi Conjugated ◽  
Pi Conjugated Polymers ◽  
Long Chain

Organic solar cells (OSC) generally contain long-chain $\pi$-conjugated polymers as donor materials, but, more recently, small-molecule donors have also attracted considerable attention. The nature of these compounds is of crucial...

Effective conjugation in conjugated polymers with strongly twisted backbones: a case study on fluorinated MEHPPV

2016 ◽  
Vol 4 (28) ◽  
pp. 6900-6906 ◽  
Author(s):  
Rim Milad ◽  
Junqing Shi ◽  
Aranzazu Aguirre ◽  
Antonio Cardone ◽  
Begoña Milián-Medina ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Conjugation Length ◽  
Effective Conjugation Length

Strongly twisted conjugated polymers demand a redefinition of the ‘effective conjugation length’, extracted here graphically by a facile method.

scholarly journals Tuning conformation, assembly, and charge transport properties of conjugated polymers by printing flow

2019 ◽  
Vol 5 (8) ◽  
pp. eaaw7757 ◽  
Author(s):  
Kyung Sun Park ◽  
Justin J. Kwok ◽  
Rishat Dilmurat ◽  
Ge Qu ◽  
Prapti Kafle ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Charge Transport ◽  
High Performance ◽  
Morphological Transition ◽  
Assembly Process ◽  
Conformation Change ◽  
Conjugation Length ◽  
Polymer Backbone ◽  
Fourfold Increase ◽  
Molecular Semiconductors

Intrachain charge transport is unique to conjugated polymers distinct from inorganic and small molecular semiconductors and is key to achieving high-performance organic electronics. Polymer backbone planarity and thin film morphology sensitively modulate intrachain charge transport. However, simple, generic nonsynthetic approaches for tuning backbone planarity and the ensuing multiscale assembly process do not exist. We first demonstrate that printing flow is capable of planarizing the originally twisted polymer backbone to substantially increase the conjugation length. This conformation change leads to a marked morphological transition from chiral, twinned domains to achiral, highly aligned morphology, hence a fourfold increase in charge carrier mobilities. We found a surprising mechanism that flow extinguishes a lyotropic twist-bend mesophase upon backbone planarization, leading to the observed morphology and electronic structure transitions.

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

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