A direct approach to study radiative emission from triplet excitations in molecular semiconductors and conjugated polymers

2008 ◽  
Vol 129 (4) ◽  
pp. 041103 ◽  
Author(s):  
Jai Singh ◽  
H. Baessler ◽  
S. Kugler
Keyword(s):  
Conjugated Polymers ◽  
Direct Approach ◽  
Radiative Emission ◽  
Molecular Semiconductors

Highly air-stable, n-doped conjugated polymers achieved by dimeric organometallic dopants

2021 ◽  
Author(s):  
Yu Yamashita ◽  
Samik Jhulki ◽  
Dinesh Bhardwaj ◽  
Elena Longhi ◽  
Shohei Kumagai ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Work Function ◽  
Electronic Properties ◽  
Chemical Doping ◽  
Doped Polymers ◽  
Molecular Semiconductors

Chemical doping is a key process for controlling the electronic properties of molecular semiconductors, including their conductivity and work function. A common limitation of n-doped polymers is their instability under...

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.

scholarly journals Charge transport in high-mobility conjugated polymers and molecular semiconductors

2020 ◽  
Vol 19 (5) ◽  
pp. 491-502 ◽  
Author(s):  
Simone Fratini ◽  
Mark Nikolka ◽  
Alberto Salleo ◽  
Guillaume Schweicher ◽  
Henning Sirringhaus
Keyword(s):  
Conjugated Polymers ◽  
Charge Transport ◽  
High Mobility ◽  
Molecular Semiconductors

Information and estimation in image processing

1987 ◽  
Vol 45 ◽  
pp. 14-17
Author(s):  
B. Roy Frieden
Keyword(s):  
Image Processing ◽  
Optical System ◽  
Large Amplitude ◽  
Communication Theory ◽  
Image Data ◽  
Direct Approach ◽  
Ill Posed

Despite the skill and determination of electro-optical system designers, the images acquired using their best designs often suffer from blur and noise. The aim of an “image enhancer” such as myself is to improve these poor images, usually by digital means, such that they better resemble the true, “optical object,” input to the system. This problem is notoriously “ill-posed,” i.e. any direct approach at inversion of the image data suffers strongly from the presence of even a small amount of noise in the data. In fact, the fluctuations engendered in neighboring output values tend to be strongly negative-correlated, so that the output spatially oscillates up and down, with large amplitude, about the true object. What can be done about this situation? As we shall see, various concepts taken from statistical communication theory have proven to be of real use in attacking this problem. We offer below a brief summary of these concepts.

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.

Direct Approach for Jugular Paraganglioma by Enlarged Mastoidectomy and Hypotympanotomy without Middle Ear Obliteration

2016 ◽  
Vol 77 (S 02) ◽  
Author(s):  
Kazimierz Niemczyk ◽  
Robert Bartoszewicz ◽  
Krzysztof Morawski ◽  
Izabela Popieluch
Keyword(s):  
Middle Ear ◽  
Direct Approach

Photoactive donor-acceptor thin films as prospective materials for evaporated bulk heterojunctions of molecular semiconductors

2008 ◽  
Author(s):  
Derck Schlettwein ◽  
Robin Knecht ◽  
Dominik Klaus ◽  
Christopher Keil ◽  
Günter Schnurpfeil
Keyword(s):  
Thin Films ◽  
Bulk Heterojunctions ◽  
Donor Acceptor ◽  
Molecular Semiconductors

Oriented Luminescent Nanostructures From Single Molecules Of Conjugated Polymers

2003 ◽  
Vol 771 ◽  
Author(s):  
Adosh Mehta ◽  
Pradeep Kumar ◽  
Jie Zheng ◽  
Robert M. Dickson ◽  
Bobby Sumpter ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Polarization Anisotropy ◽  
Emission Pattern ◽  
Spectral Signatures ◽  
Dipole Emission ◽  
Ink Jet ◽  
Molecular Scale ◽  
Jet Printing ◽  
Photochemical Stability ◽  
Printing Techniques

AbstractDipole emission pattern imaging experiments on single chains of common conjugated polymers (solubilized poly phenylene vinylenes) isolated by ink-jet printing techniques have revealed surprising uniformity in transition moment orientation perpendicular to the support substrate. In addition to uniform orientation, these species show a number of striking differences in photochemical stability, polarization anisotropy,[1] and spectral signatures[2] with respect to similar (well-studied) molecules dispersed in dilute thin-films. Combined with molecular mechanics simulation, these results point to a structural picture of a folded macromolecule as a highly ordered cylindrical nanostructure whose long-axis (approximately collinear with the conjugation axis) is oriented, by an electrostatic interaction, perpendicular to the coverglass substrate. These results suggest a number of important applications in nanoscale photonics and molecular-scale optoelectronics.

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