The Synthesis And Optoelectronic Properties Of Oxadiazole-Based Polymers

1995 ◽  
Vol 413 ◽  
Author(s):  
X.-C. Li ◽  
A. Kraft ◽  
R. Cervini ◽  
G. C. W. Spencer ◽  
F. Cacialli ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Molecular Orbital ◽  
Main Chain ◽  
Polymeric Materials ◽  
Side Chain ◽  
Major Conclusion ◽  
Electroluminescent Device ◽  
Highest Occupied Molecular Orbital ◽  
Electron Transporting Layer

ABSTRACTNew oxadiazole-based polymeric materials have been synthesized either as side chain copolymers with polymethacrylate or as main chain copolymers carrying solubilizing elements such as hexafluoropropylidene or meta-linked aromatic spacer units. Many of these materials exhibit blue luminescence in the solid state. The materials have been evaluated by photoluminescence and cyclic voltammetry studies, and as the electron transporting layer in a two-layer electroluminescent device with poly(p-phenylenevinylene) (PPV) as the emissive layer. The major conclusion is that these materials function by providing large heterojunction offsets at the Highest Occupied Molecular Orbital (HOMO) which block the passage of holes through the device.

Thermosetting Mechanism Study of Organosilicon Polymer Containing Carborane by Solid-State NMR Spectroscopy

1999 ◽  
Vol 576 ◽  
Author(s):  
H. Kimura ◽  
K. Okita ◽  
M. Ichitani ◽  
M. Yonezawa ◽  
T. Sugimoto
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Main Chain ◽  
Addition Reaction ◽  
Side Chain ◽  
Mechanism Study ◽  
Nmr Method ◽  
Organosilicon Polymer ◽  
Thermal Stable

ABSTRACTThe thermosetting mechanism of an organosilicon polymer containing carborane has been studied utilizing the 13and 29Si solid-state NMR method. The polymer having C≡C bonds in the main chain and CH═CH2, Si-H bonds, and carborane in the bulky side chain, shows a very highly thermal stability in air by curing. From 13C and 29Si NMR spectra of the polymer, it was found that the intermolecular cross-linking reactions of the polymer was due to (1) the diene reaction between Ph-C≡C and C≡C and (2) the addition reaction between side chain terminal and Ph-C≡C and between CH═CH2 and Si–H, and a very highly thermal stable structure is formed.

Side chain modification: an effective approach to modulate the energy level of benzodithiophene based polymers for high-performance solar cells

2015 ◽  
Vol 3 (35) ◽  
pp. 18115-18126 ◽  
Author(s):  
Haimei Wu ◽  
Baofeng Zhao ◽  
Weiping Wang ◽  
Zhaoqi Guo ◽  
Wei Wei ◽  
...  
Keyword(s):  
Solar Cells ◽  
Energy Level ◽  
Conjugated Polymers ◽  
Molecular Orbital ◽  
High Performance ◽  
Bulk Heterojunction ◽  
Polymer Solar Cells ◽  
Side Chain ◽  
The Past ◽  
Highest Occupied Molecular Orbital

Over the past few years, it has been proven that deepening the highest occupied molecular orbital (HOMO) levels of conjugated polymers is one of the most successful strategies to develop novel materials for high performance bulk heterojunction polymer solar cells.

Impact of side-chain fluorination on photovoltaic properties: fine tuning of the microstructure and energy levels of 2D-conjugated copolymers

2017 ◽  
Vol 5 (32) ◽  
pp. 16702-16711 ◽  
Author(s):  
Jisoo Shin ◽  
Min Kim ◽  
Boseok Kang ◽  
Jaewon Lee ◽  
Heung Gyu Kim ◽  
...  
Keyword(s):  
Solar Cells ◽  
Molecular Orbital ◽  
Polymer Solar Cells ◽  
Energy Levels ◽  
Fine Tuning ◽  
Side Chain ◽  
Photovoltaic Properties ◽  
Highly Efficient ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

The control of the molecular energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is crucial to the design of highly efficient polymer solar cells (PSCs).

scholarly journals Main-Chain Chiral Poly(2-oxazoline)s: Influence of Alkyl Side-Chain on Secondary Structure Formation in the Solid State

2015 ◽  
Vol 350 (1) ◽  
pp. 43-54 ◽  
Author(s):  
Meta M. Bloksma ◽  
Marco M. R. M. Hendrix ◽  
Silke Rathgeber ◽  
Ulrich S. Schubert ◽  
Richard Hoogenboom
Keyword(s):  
Solid State ◽  
Secondary Structure ◽  
Structure Formation ◽  
Main Chain ◽  
Side Chain ◽  
Alkyl Side Chain ◽  
Secondary Structure Formation

Influence of Electrostatic Interactions on Chain Dynamics and Morphological Development in Perfluorosulfonate Ionomer Membranes

2004 ◽  
Vol 856 ◽  
Author(s):  
Kirt A. Page ◽  
Robert B. Moore
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Small Angle ◽  
Electrostatic Interactions ◽  
Main Chain ◽  
Variable Temperature ◽  
Side Chain ◽  
Morphological Development ◽  
Chain Dynamics ◽  
Side Band

ABSTRACTSeveral high temperature methods of processing Nafion® have been developed using various alkylammonium ion forms of the ionomer, and the choice of counterion has been shown to have a significant effect on the thermal and mechanical properties of this material. In particular, it has been shown that neutralization gives rises to two high-temperature mechanical relaxations as observed in dynamic mechanical analysis (DMA). While several studies in the literature have attempted to explain the molecular origins of these mechanical relaxations, the assignments were based primarily on limited DMA results and have at times been contradictory. The study presented here is a fundamental investigation into the molecular origins of the thermally induced morphological relaxations and dynamics of alkylammonium forms of Nafion® membranes as studied by variable temperature small-angle x-ray scattering (SAXS) and solid-state 19F NMR spectroscopy. The intensity of the small-angle ionomer peak at ca. q = 2 nm–1 was monitored as a function of temperature for each alkylammonium neutralized sample in unoriented and oriented states. In the case of the oriented samples, the degree of anisotropic scattering from the oriented ionomer morphology was quantified using the Hermann's orientation function and monitored as a function of temperature. Changes in intensity of the ionomer peak and the Hermann's parameter as a function of temperature were shown to correlate well with relaxations observed in DMA. Several variable temperature solid-state 19F NMR techniques (including spin diffusion, side-band analysis and T1ρ experiments) were used to investigate the dynamics of the Nafion® chains. Side band analysis indicated that the side-chain is more mobile than the main chain and that the mobility is greatly affected by the size of the counterion. Changes in side-band intensity as a function of temperature were shown to correlate well with DMA data. Results from T1ρ experiments show strong counterion dependence and suggest coupled main- and side-chain motions. A two-component relaxation process was also observed for the main-chain fluorines. The results of the NMR investigations, along with the SAXS data, have led to the development of a more detailed description of the dynamics of Nafion® and the molecular origins of the mechanical relaxations. With this information, the continuing goal to determine how the strength of the electrostatic interactions in perfluorosulfonate ionomers affects the chain dynamics and developing morphology may be realized for the purpose of controlling the morphology to create more efficient ionomeric membrane materials.

Second-Order Nonlinear Optical Polymers With Different Chromophore Arrangements

1993 ◽  
Vol 328 ◽  
Author(s):  
Bo Wu ◽  
Chengzeng Xu ◽  
Larry R. Dalton ◽  
Srinath Kalluri ◽  
Yongqiang Shi ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Main Chain ◽  
Second Harmonic ◽  
Polymeric Materials ◽  
Second Order ◽  
Side Chain ◽  
Optical Polymers ◽  
Nonlinear Optical Polymers ◽  
Main Chain Polymers

ABSTRACTSecond-order nonlinear optical polymers can be divided into four groups regarding arrangements of chromophore dipoles in polymer backbones, namely, side-chain polymers, random, head-to-tail, and head-to-head Main-chain polymers. A variety of polymers with the aforementioned configurations have been designed and synthesized from functionalized amino-nitro azobenzene chromophores. Poling processes of these polymeric materials have been investigated by in-situ poling and second-harmonic generation detection.

Radical Enzymes Control the Chemistry of Their Highly Reactive Intermediates Using the Quantum Coulombic Effect

2020 ◽  
Author(s):  
Hossein Khalilian ◽  
Gino A. DiLabio
Keyword(s):  
Hydrogen Bonding ◽  
Molecular Orbital ◽  
Reactive Intermediates ◽  
Hydrogen Bonding Interaction ◽  
Orbital Ordering ◽  
Dynamic Nature ◽  
Radical Intermediate ◽  
Highest Occupied Molecular Orbital ◽  
Bonding Interaction ◽  
Close Proximity

Here, we report an exquisite strategy that the B12 enzymes exploit to manipulate the reactivity of their radical intermediate (Adenosyl radical). Based on the quantum-mechanic calculations, these enzymes utilize a little known long-ranged through space quantum Coulombic effect (QCE). The QCE causes the radical to acquire an electronic structure that contradicts the Aufbau Principle: The singly-occupied molecular orbital (SOMO) is no longer the highest-occupied molecular orbital (HOMO) and the radical is unable to react with neighbouring substrates. The dynamic nature of the enzyme and its structure is expected to be such that the reactivity of the radical is not restored until it is moved into close proximity of the target substrate. We found that the hydrogen bonding interaction between the nearby conserved glutamate residue and the ribose ring of Adenosyl radical plays a crucial role in manipulating the orbital ordering

Radical Enzymes Control the Chemistry of Their Highly Reactive Intermediates Using the Quantum Coulombic Effect

2020 ◽  
Author(s):  
Hossein Khalilian ◽  
Gino A. DiLabio
Keyword(s):  
Hydrogen Bonding ◽  
Molecular Orbital ◽  
Reactive Intermediates ◽  
Hydrogen Bonding Interaction ◽  
Orbital Ordering ◽  
Dynamic Nature ◽  
Radical Intermediate ◽  
Highest Occupied Molecular Orbital ◽  
Bonding Interaction ◽  
Close Proximity

Here, we report an exquisite strategy that the B12 enzymes exploit to manipulate the reactivity of their radical intermediate (Adenosyl radical). Based on the quantum-mechanic calculations, these enzymes utilize a little known long-ranged through space quantum Coulombic effect (QCE). The QCE causes the radical to acquire an electronic structure that contradicts the Aufbau Principle: The singly-occupied molecular orbital (SOMO) is no longer the highest-occupied molecular orbital (HOMO) and the radical is unable to react with neighbouring substrates. The dynamic nature of the enzyme and its structure is expected to be such that the reactivity of the radical is not restored until it is moved into close proximity of the target substrate. We found that the hydrogen bonding interaction between the nearby conserved glutamate residue and the ribose ring of Adenosyl radical plays a crucial role in manipulating the orbital ordering

Experimental Assessment of the Practical Oxidative Stability of Lithium Thiophosphate Solid Electrolytes

2019 ◽  
Author(s):  
Georg Dewald ◽  
Saneyuki Ohno ◽  
Marvin Kraft ◽  
Raimund Koerver ◽  
Paul Till ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Oxidative Stability ◽  
Photoelectron Spectroscopy ◽  
Solid Electrolytes ◽  
Stability Limit ◽  
Lithium Ion ◽  
High Energy ◽  
Redox Activity ◽  
Solid State Batteries

<p>All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use <i>stepwise</i><i>cyclic voltammetry </i>to obtain information on the practical oxidative stability limit of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>, a Li<sub>2</sub>S‑P<sub>2</sub>S<sub>5</sub>glass, as well as the argyrodite Li<sub>6</sub>PS<sub>5</sub>Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The <i>stepwise cyclic voltammetry</i>approach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes. </p>

Experimental Assessment of the Practical Oxidative Stability of Lithium Thiophosphate Solid Electrolytes

2019 ◽  
Author(s):  
Georg Dewald ◽  
Saneyuki Ohno ◽  
Marvin Kraft ◽  
Raimund Koerver ◽  
Paul Till ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Oxidative Stability ◽  
Photoelectron Spectroscopy ◽  
Solid Electrolytes ◽  
Stability Limit ◽  
Lithium Ion ◽  
High Energy ◽  
Redox Activity ◽  
Solid State Batteries

<p>All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use <i>stepwise</i><i>cyclic voltammetry </i>to obtain information on the practical oxidative stability limit of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>, a Li<sub>2</sub>S‑P<sub>2</sub>S<sub>5</sub>glass, as well as the argyrodite Li<sub>6</sub>PS<sub>5</sub>Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The <i>stepwise cyclic voltammetry</i>approach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes. </p>

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