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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
851

<b>QUANTUM EFFECTS IN EXCITON TRANSPORT AND INTERACTION IN MOLECULAR AGGREGATES</b>

Sarath Kumar (17544861) 05 December 2023 (has links)
<p dir="ltr">Long-range exciton transport, when coupled with reduced exciton-exciton annihilation (EEA), is pivotal for the enhanced performance of organic photovoltaics and the efficiency of natural light-harvesting systems. This thesis explores strategies to optimize exciton transport and EEA rates in molecular materials by manipulating the quantum nature of excitons, particularly exciton delocalization. In addition, we also aim to understand factors limiting the transport of delocalized excitons within molecular materials. To this end, self-assembled perylene diimide (PDI) molecular aggregates are ideal candidates for this study due to their conducive properties for engineering exciton delocalization. <b>Chapter 1 </b>establishes a fundamental understanding of exciton delocalization, outlining strategies to tune this phenomenon within PDI aggregates and presenting the open questions this thesis addresses. <b>Chapter 2 </b>details the synthesis of PDI aggregates and delineates the spectroscopic techniques used for characterization, including steady-state absorption and emission, transient photoluminescence (PL), and transient absorption spectroscopy. It also describes the microscopy methods implemented to visualize exciton transport, such as transient PL microscopy and transient absorption microscopy (TAM). <b>Chapter 3 </b>introduces the thesis's primary theme: the suppression of exciton-exciton annihilation (EEA) in molecular aggregates through quantum interference. This chapter demonstrates that the spatial phase relationship of delocalized excitons is crucial in EEA, with band bottom excitons in H aggregates exhibiting an oscillating spatial phase relationship displaying a coherent suppression of EEA. <b>Chapter 4 </b>discusses how coupling to static and dynamic disorder affects coherent exciton propagation. High spatial and temporal resolution TAM experiments, along with temperature-dependent studies, help disentangle the contributions of static and dynamic disorder to exciton transport. <b>Chapter 5 </b>delves into the concept of band shape engineering, whereby the microscopic electronic couplings within PDI aggregates are fine-tuned by altering the packing motifs to regulate exciton transport. Through low-temperature TAM experiments, this chapter illustrates how the interplay between long-range Coulombic and short-range charge transfer electronic couplings can determine exciton bandwidth and influence the coherent propagation of excitons. <b>Chapter 6 </b>provides a summary of the work and discusses future directions, paving the way for continued exploration in the field of exciton transport and interaction in molecular aggregates.</p>
852

Activation of Enediynes by Photochemical Ring Contraction: Design, Synthesis and Reactivity of Cyclic Enediynes Containing Diazodicarbonyl Moiety

Karpov, Grigori V. January 2006 (has links)
No description available.
853

Photoaffinity Labeling Via Nitrenium Ion Chemistry: The Photochemistry of 4-aminophenylazides

Voskresenska, Valentyna D. 15 March 2011 (has links)
No description available.
854

Early Events in Photochemistry of Aryl Azides Used as Photoaffinity Labeling Agents

Panov, Maxim S. 22 November 2011 (has links)
No description available.
855

COMPUTATIONAL AND SPECTROSCOPIC STUDIES OF THE PHOTOCHEMISTRY AND PHOTOPHYSICS OF DIPHOSPHENES

Peng, Huo-Lei 21 March 2007 (has links)
No description available.
856

Photophysical Properties of Amphiphilic Naphthalene Diimide Nanoassemblies and Cadmium Sulfide Nanoparticles and Poly(phenylene-ethynylene) Nanocomposites

Romano, Natalie C. January 2014 (has links)
No description available.
857

Metal-Carbon (Metal = Iridium(III) and Gold(III)) Bond Formation Under Transmetalation and Catalytic Conditions; Metallonucleosides as Anticancer Drugs and Bio-photonic Probes; and Synthesis of Iridium Fluoride Complexes.

Maity, Ayan 06 February 2015 (has links)
No description available.
858

Structural Characterization and Spectroscopic Investigation of Isomerization Dynamics inPhotochromic Polypyridyl Ruthenium(II) Chelating mono- and bis-Sulfoxide Complexes

King, Albert W. 25 August 2015 (has links)
No description available.
859

Ultrafast Excited State Investigation of Ruthenium and Osmium Polypyridyl SulfoxideComplexes and BOPHY Dyes

Wang, Lei 17 September 2015 (has links)
No description available.
860

Design, synthesis, and characterization of photoresponsive materials usingcoordination bonds and other supramolecular interactions

Razgoniaev, Anton 01 December 2017 (has links)
No description available.

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