scholarly journals Direct observation of backbone planarization via side-chain alignment in single bulky-substituted polythiophenes

2018 ◽  
Vol 115 (11) ◽  
pp. 2699-2704 ◽  
Author(s):  
Dominic Raithel ◽  
Lena Simine ◽  
Sebastian Pickel ◽  
Konstantin Schötz ◽  
Fabian Panzer ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Electronic Properties ◽  
Red Shift ◽  
Structural Motif ◽  
Side Chain ◽  
Side Chains ◽  
Single Chain ◽  
Optical And Electronic Properties ◽  
Backbone Conformation ◽  
The Impact

The backbone conformation of conjugated polymers affects, to a large extent, their optical and electronic properties. The usually flexible substituents provide solubility and influence the packing behavior of conjugated polymers in films or in bad solvents. However, the role of the side chains in determining and potentially controlling the backbone conformation, and thus the optical and electronic properties on the single polymer level, is currently under debate. Here, we investigate directly the impact of the side chains by studying the bulky-substituted poly(3-(2,5-dioctylphenyl)thiophene) (PDOPT) and the common poly(3-hexylthiophene) (P3HT), both with a defined molecular weight and high regioregularity, using low-temperature single-chain photoluminescence (PL) spectroscopy and quantum-classical simulations. Surprisingly, the optical transition energy of PDOPT is significantly (∼2,000 cm−1 or 0.25 eV) red-shifted relative to P3HT despite a higher static and dynamic disorder in the former. We ascribe this red shift to a side-chain induced backbone planarization in PDOPT, supported by temperature-dependent ensemble PL spectroscopy. Our atomistic simulations reveal that the bulkier 2,5-dioctylphenyl side chains of PDOPT adopt a clear secondary helical structural motif and thus protect conjugation, i.e., enforce backbone planarity, whereas, for P3HT, this is not the case. These different degrees of planarity in both thiophenes do not result in different conjugation lengths, which we found to be similar. It is rather the stronger electronic coupling between the repeating units in the more planar PDOPT which gives rise to the observed spectral red shift as well as to a reduced calculated electron−hole polarization.

Electronic properties of isoindigo-based conjugated polymers bearing urea-containing and linear alkyl side chains

2018 ◽  
Vol 6 (44) ◽  
pp. 12070-12078 ◽  
Author(s):  
Brynn P. Charron ◽  
Michael U. Ocheje ◽  
Mariia Selivanova ◽  
Arthur D. Hendsbee ◽  
Yuning Li ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Electronic Properties ◽  
Side Chain ◽  
Side Chains ◽  
Engineering Study ◽  
Alkyl Side Chains

A side-chain engineering study has been performed with isoindigo-based conjugated polymers to modulate their physical and electronic properties through the incorporation of urea-containing and saturated linear side chains.

Synthesis and optoelectronic properties of benzodithiophene-based conjugated polymers with hydrogen bonding nucleobase side chain functionality

2020 ◽  
Vol 11 (36) ◽  
pp. 5735-5749
Author(s):  
Sina Sabury ◽  
Tyler J. Adams ◽  
Margaret Kocherga ◽  
S. Michael Kilbey ◽  
Michael G. Walter
Keyword(s):  
Thin Films ◽  
Hydrogen Bonding ◽  
Conjugated Polymers ◽  
Electronic Properties ◽  
Molecular Assembly ◽  
Optoelectronic Properties ◽  
Side Chain ◽  
Alternating Copolymers ◽  
Optical And Electronic Properties

Nucleobase functionalities in conjugated, alternating copolymers participate in interbase hydrogen bonding, which promotes molecular assembly and organization in thin films and enhances optical and electronic properties.

Synergy strategy to the flexible alkyl and chloride side-chain engineered quinoxaline-based D–A conjugated polymers for efficient non-fullerene polymer solar cells

2021 ◽  
Author(s):  
Liang Zeng ◽  
Ruijie Ma ◽  
Qiang Zhang ◽  
Tao Liu ◽  
Yiqun Xiao ◽  
...  
Keyword(s):  
Solar Cells ◽  
Conjugated Polymers ◽  
Halogen Atom ◽  
Polymer Solar Cells ◽  
Fine Tuning ◽  
Side Chain ◽  
Side Chains

We are developing both copolymers with quinoxaline (Qx) as acceptor units by fine tuning the side chains with halogen atom chlorine (Cl) and flexible alkyl engineering for efficient non-fullerene polymer solar cells.

scholarly journals Green-Solvent-Processed Conjugated Polymers for Organic Solar Cells: The Impact of Oligoethylene Glycol Side Chains

2019 ◽  
Vol 1 (4) ◽  
pp. 804-814 ◽  
Author(s):  
Zheng Chen ◽  
Liang Yan ◽  
Jeromy James Rech ◽  
Jun Hu ◽  
Qianqian Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Conjugated Polymers ◽  
Organic Solar Cells ◽  
Side Chains ◽  
Green Solvent ◽  
Oligoethylene Glycol ◽  
The Impact

scholarly journals Controlled steric selectivity in molecular doping towards closest-packed supramolecular conductors

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Shinya Kohno ◽  
Yu Yamashita ◽  
Naotaka Kasuya ◽  
Tsubasa Mikie ◽  
Itaru Osaka ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Steric Effects ◽  
Side Chain ◽  
Side Chains ◽  
Void Space ◽  
Alkyl Side Chains ◽  
Recent Developments ◽  
High Carrier ◽  
Molecular Doping ◽  
Steric Selectivity

Abstract Recent developments in molecular doping technologies allow extremely high carrier densities in polymeric semiconductors, exhibiting great diversity because of the unique size, conformation, and steric effect of molecular dopants. However, it is controversial how steric effects can limit the doping efficiency and to what extent dopants can be accommodated in polymers. Here, we employ two distinct conjugated polymers with different alkyl side-chain densities, where polymers are doped via anion-change, allowing greater variation in the incorporation of molecular dopants having different electrostatic potentials and shapes. We characterize the doping efficiency with regard to steric effects, considering the unique void space in the conjugated polymers. Our study reveals that doping efficiency of polymers with sparse alkyl side-chains is significantly greater than that with dense side-chains. A closest-packed supramolecule is realized with a particular combination of a sparse polymer and a large dopant, giving rise to high conductivity, air stability, and remarkably high work function. This work provides a critical insight into overcoming steric effects in molecular doping.

Low band gap conjugated polymers combining siloxane-terminated side chains and alkyl side chains: side-chain engineering achieving a large active layer processing window for PCE > 10% in polymer solar cells

2017 ◽  
Vol 5 (33) ◽  
pp. 17619-17631 ◽  
Author(s):  
Xuncheng Liu ◽  
Li Nian ◽  
Ke Gao ◽  
Lianjie Zhang ◽  
Lechi Qing ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Active Layer ◽  
Polymer Solar Cells ◽  
Hole Transport ◽  
Random Copolymers ◽  
Side Chain ◽  
Active Layer Thickness ◽  
Side Chains ◽  
Alkyl Side Chains ◽  
Thickness Tolerance

Side-chain random copolymers show high 3-D hole transport and offer excellent active layer thickness tolerance.

scholarly journals Impact of sterilization on a conjugated polymer based bioelectronic patch

2021 ◽  
Author(s):  
Yihan Yan ◽  
Lorenzo Travaglini ◽  
Kieran Lau ◽  
Jelena Rnjak-Kovacina ◽  
Minoo Eslami ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Conjugated Polymers ◽  
Electronic Properties ◽  
Conjugated Polymer ◽  
Active Material ◽  
High Dose ◽  
Γ Irradiation ◽  
The Impact

ABSTRACTTranslation into the clinic of organic bioelectronic devices having conjugated polymers as the active material will hinge on their long-term operation in vivo. This will require the device to be subject to clinically approved sterilization techniques without a deterioration in its physical and electronic properties. To date, there remains a gap in the literature addressing the impact of this critical pre-operative procedure on the properties of conjugated polymers. This study aims to address this gap by assessing the physical and electronic properties of a sterilized porous bioelectronic patch having polyaniline as the conjugated polymer. The patch was sterilized by autoclave, ethylene oxide and gamma (γ-) irradiation at 15, 25, and 50 kGy doses. Autoclaving resulted in cracking and macroscopic degradation of the patch, while patches sterilized by γ-irradiation at 50 kGy exhibited reduced mechanical and electronic properties, attributed to chain scission and non-uniform crosslinking caused by the high dose irradiation. Ethylene oxide and γ-irradiation at 15 and 25 kGy sterilization appeared to be the most effective at maintaining the mechanical and electronic properties of the patch, as well as inducing a minimal immune response as revealed by a receding fibrotic capsule after 4 weeks implantation. Our findings pave the way towards closing the gap for the translation of organic bioelectronic devices from acute to long-term in vivo models.

scholarly journals Unexpected Trends in the Hydrophobicity of Fluorinated Amino Acids Reflect Competing Changes in Polarity and Conformation

2018 ◽  
Author(s):  
João R. Robalo ◽  
Ana Vila Verde
Keyword(s):  
Amino Acids ◽  
Free Energy ◽  
Side Chain ◽  
Side Chains ◽  
Hydration Free Energy ◽  
Crossover Point ◽  
Fluorinated Amino Acids ◽  
Road Map ◽  
Alkyl Side Chains ◽  
The Impact

<div><div><div><p>Fluorination can dramatically improve the thermal and proteolytic stability of proteins and their enzymatic activity. Key to the impact of fluorination on protein properties is the hydrophobicity of fluorinated amino acids. We use molecular dynamics simulations, together with a new fixed-charge, atomistic force field, to quantify the changes in hydration free energy for amino acids with alkyl side chains and with 1 to 6 –CH to –CF side chain substitutions. Fluorination changes the hydration free energy by 1.5 to +2 kcal mol<sup>-</sup>1, but the number of fluorines is a poor predictor of hydrophobicity. Changes in hydration free energy reflect two main contributions: i) fluorination alters side chain-water interactions; we identify a crossover point from hydrophilic to hydrophobic fluoromethyl groups which may be used to estimate the hydrophobicity of fluorinated alkyl side-chains; ii) fluorination alters the number of backbone-water hydrogen bonds via changes in the relative side chain-backbone conformation. Our results offer a road map to mechanistically understand how fluorination alters hydrophobicity of (bio)polymers.</p></div></div></div>

The Impact of Twisting on the Intersystem Crossing in Acenes: An Experimental and Computational Study

2022 ◽  
Author(s):  
Partha Malakar ◽  
Veniamin Borin ◽  
Anjan Bedi ◽  
Igor Schapiro ◽  
Ori Gidron ◽  
...  
Keyword(s):  
Excited State ◽  
Electronic Properties ◽  
Light Harvesting ◽  
Computational Study ◽  
Dominant Role ◽  
Intersystem Crossing ◽  
Side Group ◽  
Excited State Dynamics ◽  
Optical And Electronic Properties ◽  
The Impact

Due to their unique excited state dynamics, acenes play a dominant role in optoelectronic and light-harvesting applications. Their optical and electronic properties are typically tailored by side-group engineering, which often...

A new aspect of cyclopentadithiophene based polymers: narrow band gap polymers upon protonation

2015 ◽  
Vol 51 (67) ◽  
pp. 13229-13232 ◽  
Author(s):  
Tao Tang ◽  
Tingting Lin ◽  
FuKe Wang ◽  
Chaobin He
Keyword(s):  
Conjugated Polymers ◽  
Band Gap ◽  
Electronic Properties ◽  
Narrow Band ◽  
Optical And Electronic Properties ◽  
Significant Change

A new aspect of CPDT based conjugated polymers that CPDT units in the polymers can be protonated with a significant change in optical and electronic properties was reported.

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