Time-Resolved EPR Investigation of Potential Model Systems for Acrylate Polymer Main Chain Radicals Based on Esters of Kemp’s Tri-Acid

2009 ◽  
Vol 113 (19) ◽  
pp. 6623-6629 ◽  
Author(s):  
Natalia V. Lebedeva ◽  
Elena V. Gorelik ◽  
Damaris Magnus-Aryitey ◽  
Terence E. Hill ◽  
Malcolm D. E. Forbes
Keyword(s):  
Potential Model ◽  
Main Chain ◽  
Model Systems ◽  
Time Resolved ◽  
Polymer Main Chain ◽  
Acrylate Polymer

scholarly journals The role of spin in the degradation of organic photovoltaics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ivan Ramirez ◽  
Alberto Privitera ◽  
Safakath Karuthedath ◽  
Anna Jungbluth ◽  
Johannes Benduhn ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Bulk Heterojunction ◽  
Critical Factor ◽  
Model Systems ◽  
Transient Absorption Spectroscopy ◽  
Triplet States ◽  
Paramagnetic Resonance ◽  
Time Resolved ◽  
A Charge

AbstractStability is now a critical factor in the commercialization of organic photovoltaic (OPV) devices. Both extrinsic stability to oxygen and water and intrinsic stability to light and heat in inert conditions must be achieved. Triplet states are known to be problematic in both cases, leading to singlet oxygen production or fullerene dimerization. The latter is thought to proceed from unquenched singlet excitons that have undergone intersystem crossing (ISC). Instead, we show that in bulk heterojunction (BHJ) solar cells the photo-degradation of C60 via photo-oligomerization occurs primarily via back-hole transfer (BHT) from a charge-transfer state to a C60 excited triplet state. We demonstrate this to be the principal pathway from a combination of steady-state optoelectronic measurements, time-resolved electron paramagnetic resonance, and temperature-dependent transient absorption spectroscopy on model systems. BHT is a much more serious concern than ISC because it cannot be mitigated by improved exciton quenching, obtained for example by a finer BHJ morphology. As BHT is not specific to fullerenes, our results suggest that the role of electron and hole back transfer in the degradation of BHJs should also be carefully considered when designing stable OPV devices.

scholarly journals Using Time-Resolved Fluorescence Anisotropy of di-4-ANEPPDHQ and F2N12S to Analyze Lipid Packing Dynamics in Model Systems

2019 ◽  
Vol 29 (2) ◽  
pp. 347-352 ◽  
Author(s):  
Harmen B. B. Steele ◽  
Matthew J. Sydor ◽  
Donald S. Anderson ◽  
Andrij Holian ◽  
J. B. Alexander Ross
Keyword(s):  
Fluorescence Anisotropy ◽  
Model Systems ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Lipid Packing

Synthesis and Characterization of Low Content of Structural Defects of Aryl-Substituted Electroluminescent Poly(p-phenylenevinylene)s

2001 ◽  
Vol 665 ◽  
Author(s):  
Zhi-Kuan Chen ◽  
Nancy Hoi Sim Lee ◽  
Wei Huang
Keyword(s):  
Thermal Stability ◽  
Quantum Efficiency ◽  
Defect Structure ◽  
Main Chain ◽  
Structural Defects ◽  
Synthesis And Characterization ◽  
Good Thermal Stability ◽  
H Nmr ◽  
Polymer Main Chain

ABSTRACTWe report the synthesis and characterization of a novel series of aryl-substituted PPVs, which have shown excellent processability, good thermal stability, high photoluminescence quantum efficiency and low content of structural defects. The substituents of the polymers were designed with different degree of hindrance effect on the main chain. 1H NMR measurement indicates that the defect structure in the polymer main chain can be effectively depressed by introducing bulk and hindrance substituents.

New Host-Guest Polymeric System for Thermal Stability Enhancement of Electro Optic Effect

2002 ◽  
Vol 725 ◽  
Author(s):  
Seung Koo Park ◽  
Jung Yun Do ◽  
Jung-Jin Ju ◽  
Suntak Park ◽  
Myung-Hyun Lee
Keyword(s):  
Thermal Stability ◽  
Model Compound ◽  
Main Chain ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
New Host ◽  
Polymer Main Chain ◽  
Electro Optic ◽  
Chromophore Concentration ◽  
Stability Enhancement

AbstractA new host-guest electro optic (EO) polymer, in which a chromophore can be reacted with the polymer main chain during poling to give the corresponding side-chain EO polymer, has been prepared for improving EO effect and its thermal stability. Polyisoimide (PII) synthesized from 2, 2-bis (4-aminophenyl) hexafluoropropane and oxydiphthalic anhydride and Disperse Red 1 (DR1) were used as a host and a guest, respectively. A model compound reaction and Infrared spectra of the host-guest film after annealing at various temperatures show that the reaction between the isoimide groups in PII and the hydroxyl groups in DR1 occurs around 140 °C. The glass transition temperatures of the resulting EO polyamic aicd ester-imide copolymer with 0, 10, 20 and 30 wt. % of chromophore concentration were 275, 219, 160, and 124 °C, respectively. The EO coefficient obtained at a wavelength of 1.55 νm was 5.3 and 10.5 pm/V from the EO polymer film with 20 and 30 wt. % DR1. The EO signals exhibited only a slight decay at high temperature due to the chemical reaction between the host and guest during poling.

Synthesis of novel organic-soluble high-temperature aromatic polymers

1995 ◽  
Vol 7 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Yoshio Imai
Keyword(s):  
Glass Transition ◽  
High Temperature ◽  
Main Chain ◽  
Phenyl Group ◽  
Current Work ◽  
Transition Temperatures ◽  
Polymer Backbone ◽  
Glass Transition Temperatures ◽  
Aromatic Polyamides ◽  
Polymer Main Chain

This paper reviews our current work on the synthesis of new organic-soluble aromatic polyamides and polyimides having high glass transition temperatures above 300 °C. Our strategy to achieve this goal is to introduce a bulky pendant phenyl group along the polymer backbone and to incorporate a crank and twisted non-coplanar structure into the polymer main chain.

The correlation between the ionic degree of covalent bond comprising polymer main chain and the ionic yield due to mechanical fracture

Polymer ◽  
2014 ◽  
Vol 55 (8) ◽  
pp. 1917-1919 ◽  
Author(s):  
Masato Sakaguchi ◽  
Masakazu Makino ◽  
Takeshi Ohura ◽  
Tadahisa Iwata
Keyword(s):  
Main Chain ◽  
Covalent Bond ◽  
Mechanical Fracture ◽  
Polymer Main Chain

Picosecond time-resolved observation of photoinduced charge separation from the singlet excited state of porphyrin-quinone model systems

1981 ◽  
Vol 84 (2) ◽  
pp. 263-266 ◽  
Author(s):  
Masahito Migita ◽  
Tadashi Okada ◽  
Noboru Magata ◽  
Shinji Nishitani ◽  
Nobuyuki Kurata ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Separation ◽  
Model Systems ◽  
Singlet Excited State ◽  
Time Resolved ◽  
Photoinduced Charge Separation ◽  
Photoinduced Charge
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