Photoinduced Intramolecular Charge Transfer in Donor-Acceptor Biaryls and Resulting Applicational Aspects Regarding Fluorescent Probes and Solar Energy Conversion

Photoinduced Intramolecular Charge Transfer in Donor-Acceptor Biaryls and Resulting Applicational Aspects Regarding Fluorescent Probes and Solar Energy Conversion PDF Author: Michael Maus
Publisher: Universal-Publishers
ISBN: 1581120303
Category : Technology & Engineering
Languages : en
Pages : 223

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Book Description
This study is focused on the effects of photoinduced intramolecular charge transfer (CT) in three differently twisted donor-acceptor (D-A) biphenyls. Taking into account a further pair of differently twisted D-A biaryls new universal insights into the photoinduced electronic and conformation dynamics of D-A biaryls are obtained. Furthermore, possible applications in fields of solar energy conversion and fluorescence sensing of microenvironments are demonstrated. Experimental means of stationary and time-resolved (ps to s) luminescence, transient absorption (sub-ps), polarization spectroscopy, high pressure and low temperature techniques are employed in conjunction with quantum chemical calculations. Twist angle and solvent dependent electron transfer (ET) interactions between the D and A aryl moieties are responsible for the low lying and solvatochromic intramolecular CT electron band which gains unusually high intensity through strong electronic coupling of the pure 1ET with the ground (S0) and 1La state. As regards the class of biaryl compounds, for the first time, an excited state electron transfer from the D to the A could be monitored by dual spectrally separated stimulated fluorescence bands with precursor-successor relationship on a sub-ps timescale for the D-A biphenyls. It is concluded that, in additon to the electronic interaction of 1ET with S0 and 1La, the electronic interaction with a close lying 1Lb state plays a fundamental role in the ET dynamics and the 1CT-S0 transition probability in D-A biaryls. The initial photoinduced conformational relaxation occurs towards planarity in all biaryls investigated. However, various results evidence that the highly twisted D-A biphenyl additionally performs a slow "excited state intramolecular back twist rotation" leading to a solvent polarity dependent conformational equilibrium between a more planar (CT) and a more twisted (CTR) conformer in S1(1CT). Using global analysis of the biexponential fluorescence decays as a function of temperature and pressure in medium polar solvents, the kinetics, thermodynamics, viscosity control and decomposed emission spectra associated with this adiabatic photoreaction are determined. The twist angle dependent ability of the D-A biphenyls to serve as fluorescent probes of micropolarity, changes of microviscosity or matrix order, protic solvents and pH is investigated. In particular, fluorescence sensing of pH seems to be promising.

Photoinduced Intramolecular Charge Transfer in Donor-Acceptor Biaryls and Resulting Applicational Aspects Regarding Fluorescent Probes and Solar Energy Conversion

Photoinduced Intramolecular Charge Transfer in Donor-Acceptor Biaryls and Resulting Applicational Aspects Regarding Fluorescent Probes and Solar Energy Conversion PDF Author: Michael Maus
Publisher: Universal-Publishers
ISBN: 1581120303
Category : Technology & Engineering
Languages : en
Pages : 223

Get Book

Book Description
This study is focused on the effects of photoinduced intramolecular charge transfer (CT) in three differently twisted donor-acceptor (D-A) biphenyls. Taking into account a further pair of differently twisted D-A biaryls new universal insights into the photoinduced electronic and conformation dynamics of D-A biaryls are obtained. Furthermore, possible applications in fields of solar energy conversion and fluorescence sensing of microenvironments are demonstrated. Experimental means of stationary and time-resolved (ps to s) luminescence, transient absorption (sub-ps), polarization spectroscopy, high pressure and low temperature techniques are employed in conjunction with quantum chemical calculations. Twist angle and solvent dependent electron transfer (ET) interactions between the D and A aryl moieties are responsible for the low lying and solvatochromic intramolecular CT electron band which gains unusually high intensity through strong electronic coupling of the pure 1ET with the ground (S0) and 1La state. As regards the class of biaryl compounds, for the first time, an excited state electron transfer from the D to the A could be monitored by dual spectrally separated stimulated fluorescence bands with precursor-successor relationship on a sub-ps timescale for the D-A biphenyls. It is concluded that, in additon to the electronic interaction of 1ET with S0 and 1La, the electronic interaction with a close lying 1Lb state plays a fundamental role in the ET dynamics and the 1CT-S0 transition probability in D-A biaryls. The initial photoinduced conformational relaxation occurs towards planarity in all biaryls investigated. However, various results evidence that the highly twisted D-A biphenyl additionally performs a slow "excited state intramolecular back twist rotation" leading to a solvent polarity dependent conformational equilibrium between a more planar (CT) and a more twisted (CTR) conformer in S1(1CT). Using global analysis of the biexponential fluorescence decays as a function of temperature and pressure in medium polar solvents, the kinetics, thermodynamics, viscosity control and decomposed emission spectra associated with this adiabatic photoreaction are determined. The twist angle dependent ability of the D-A biphenyls to serve as fluorescent probes of micropolarity, changes of microviscosity or matrix order, protic solvents and pH is investigated. In particular, fluorescence sensing of pH seems to be promising.

Polymers in Organic Electronics

Polymers in Organic Electronics PDF Author: Sulaiman Khalifeh
Publisher: Elsevier
ISBN: 192788568X
Category : Technology & Engineering
Languages : en
Pages : 617

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Book Description
Polymers in Organic Electronics: Polymer Selection for Electronic, Mechatronic, and Optoelectronic Systems provides readers with vital data, guidelines, and techniques for optimally designing organic electronic systems using novel polymers. The book classifies polymer families, types, complexes, composites, nanocomposites, compounds, and small molecules while also providing an introduction to the fundamental principles of polymers and electronics. Features information on concepts and optimized types of electronics and a classification system of electronic polymers, including piezoelectric and pyroelectric, optoelectronic, mechatronic, organic electronic complexes, and more. The book is designed to help readers select the optimized material for structuring their organic electronic system.Chapters discuss the most common properties of electronic polymers, methods of optimization, and polymeric-structured printed circuit boards. The polymeric structures of optoelectronics and photonics are covered and the book concludes with a chapter emphasizing the importance of polymeric structures for packaging of electronic devices. Provides key identifying details on a range of polymers, micro-polymers, nano-polymers, resins, hydrocarbons, and oligomers Covers the most common electrical, electronic, and optical properties of electronic polymers Describes the underlying theories on the mechanics of polymer conductivity Discusses polymeric structured printed circuit boards, including their rapid prototyping and optimizing their polymeric structures Shows optimization methods for both polymeric structures of organic active electronic components and organic passive electronic components

Topics in Fluorescence Spectroscopy

Topics in Fluorescence Spectroscopy PDF Author: Joseph R. Lakowicz
Publisher: Springer Science & Business Media
ISBN: 0306447843
Category : Science
Languages : en
Pages : 524

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Book Description
Time-resolved fluorescence spectroscopy is widely used as a research tool in bioch- istry and biophysics. These uses of fluorescence have resulted in extensive knowledge of the structure and dynamics of biological macromolecules. This information has been gained by studies of phenomena that affect the excited state, such as the local environment, quenching processes, and energy transfer. Topics in Fluorescence Spectroscopy, Volume 4: Probe Design and Chemical Sensing reflects a new trend, which is the use of time-resolved fluorescence in analytical and clinical chemistry. These emerging applications of time-resolved fluorescence are the result of continued advances in laser detector and computer technology. For instance, pho- multiplier tubes (PMT) were previously bulky devices. Miniature PMTs are now available, and the performance of simpler detectors is continually improving. There is also considerable effort to develop fluorophores that can be excited with the red/ne- infrared (NIR) output of laser diodes. Using such probes, one can readily imagine small time-resolved fluorometers, even hand-held devices, being used fordoctor’s office or home health care.

Glucose Sensing

Glucose Sensing PDF Author: Chris D. Geddes
Publisher: Springer Science & Business Media
ISBN: 0387330151
Category : Science
Languages : en
Pages : 460

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Book Description
An essential reference for any laboratory working in the analytical fluorescence glucose sensing field. The increasing importance of these techniques is typified in one emerging area by developing non-invasive and continuous approaches for physiological glucose monitoring. This volume incorporates analytical fluorescence-based glucose sensing reviews, specialized enough to be attractive to professional researchers, yet appealing to a wider audience of scientists in related disciplines of fluorescence.

Semiconducting and Metallic Polymers

Semiconducting and Metallic Polymers PDF Author: Alan J. Heeger
Publisher: OUP Oxford
ISBN: 0198528647
Category : Science
Languages : en
Pages : 288

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Book Description
The unique properties of conducting and semiconducting (conjugated) polymers make them one of the most attractive areas of interdisciplinary materials science and technology. Written by a pioneer in the field, this book is the first aimed at teaching graduate students, postdoctoral scientists, and specialists in industry about this exciting field.

Molecular Fluorescence

Molecular Fluorescence PDF Author: Bernard Valeur
Publisher: John Wiley & Sons
ISBN: 3527328467
Category : Science
Languages : en
Pages : 595

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Book Description
This second edition of the well-established bestseller is completely updated and revised with approximately 30 % additional material, including two new chapters on applications, which has seen the most significant developments. The comprehensive overview written at an introductory level covers fundamental aspects, principles of instrumentation and practical applications, while providing many valuable tips. For photochemists and photophysicists, physical chemists, molecular physicists, biophysicists, biochemists and biologists, lecturers and students of chemistry, physics, and biology.

Time-resolved Vibrational Spectroscopy

Time-resolved Vibrational Spectroscopy PDF Author: George H. Atkinson
Publisher: Taylor & Francis
ISBN: 9782881241918
Category : Science
Languages : en
Pages : 442

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Book Description
First published in 1987. Routledge is an imprint of Taylor & Francis, an informa company.

Single Molecule Spectroscopy

Single Molecule Spectroscopy PDF Author: R. Rigler
Publisher: Springer Science & Business Media
ISBN: 3642565441
Category : Science
Languages : en
Pages : 375

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Book Description
The topics range from single molecule experiments in quantum optics and solid-state physics to analogous investigations in physical chemistry and biophysics.

Iptycenes Chemistry

Iptycenes Chemistry PDF Author: Chuan-Feng Chen
Publisher: Springer Science & Business Media
ISBN: 3642328881
Category : Science
Languages : en
Pages : 384

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Book Description
Iptycenes Chemistry: From Synthesis to Applications provides a comprehensive overview of the development of iptycene chemistry in the past seventy years. This book covers: (1) the basic nomenclature and general properties of iptycenes and their derivatives; (2) the synthesis and functionalization reactions of triptycenes, pentiptycenes, higher iptycenes, heterotriptycenes, and homotriptycenes; (3) the methods for the preparation of iptycene-based polymers with different types; and (4) the applications of iptycenes and their derivatives in molecular machines, materials science, host-guest chemistry, self-assembly, coordination chemistry, physical organic chemistry, medicinal chemistry, and so on. Consequently, such a book is not only helpful to researchers working in iptycene chemistry, but can also facilitate future research in wide areas.

New Frontiers in Photochromism

New Frontiers in Photochromism PDF Author: Masahiro Irie
Publisher: Springer Science & Business Media
ISBN: 4431542914
Category : Science
Languages : en
Pages : 298

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Book Description
Photochromism is the reversible phototransformation of a chemical species between two forms having different absorption spectra. During the phototransformation not only the absorption spectra but also various physicochemical properties change, such as the refractive index, dielectric constant, oxidation/reduction potential, and geometrical structure. The property changes can be applied to photonic equipment such as erasable memory media, photo-optical switch components, and display devices. This book compiles the accomplishments of the research project titled “New Frontiers in Photochromism” supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan. The project focused not only on the above-mentioned classical subjects in photochromism, such as color changes, optical memory, and optical switches, but also on fundamental physicochemical studies and unprecedented application fields that have not yet been explored in photochromism. The latter topics include light-driven mechanical motion, photocontrol of surface wettability, metal deposition on solid materials, photocontrol of chiral properties, ultrafast decoloration dyes, and femtosecond laser experiments, among others.