• Login
    View Item 
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UA Campus RepositoryCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournalThis CollectionTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournal

    My Account

    LoginRegister

    About

    AboutUA Faculty PublicationsUA DissertationsUA Master's ThesesUA Honors ThesesUA PressUA YearbooksUA CatalogsUA Libraries

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Molecular Engineering of Phthalocyanine Derivatives as Materials for Organic Photovoltaics

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    azu_etd_14294_sip1_m.pdf
    Size:
    17.95Mb
    Format:
    PDF
    Download
    Author
    Cao, Yu
    Issue Date
    2015
    Keywords
    Chemistry
    Advisor
    McGrath, Dominic V.
    
    Metadata
    Show full item record
    Publisher
    The University of Arizona.
    Rights
    Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
    Embargo
    Release 20-Nov-2018
    Abstract
    Phthalocyanine (Pc) derivatives are π-conjugated molecules that have been explored as active layer components in organic photovoltaics (OPVs). The structure can be modified through incorporation of metals and installation of substituents which allows modulation of Pc-based materials toward desired solubility, photophysical properties and condensed phase organization. Research efforts in this thesis can be classified as (i) modulation of Pc absorption (Q-band) toward long wavelength to provide materials for near-infrared (NIR) absorbing OPVs, and (ii) development of solution processable Pc derivatives that self-organize in thin films to ease charge transport. Chapter 1 provides a brief review of OPV technology on its working mechanism, efficiency limitations and requirements for organic semiconductor materials. Characteristic properties of Pc materials, shortcoming for OPV applications and structural modulation strategies are discussed. Literature examples of Pc derivatives as (1) NIR absorbing materials; (2) self-organizing materials; and (3) OPV additives have been summarized. One major limitation of Pc materials is their relative narrow absorption band that lies in the UV-Vis region. Since more than 50% of solar radiation is incident in the NIR region, there has been increasing interest of tuning Pc absorption toward the NIR, which demands reasonable manipulation of the optical bandgap. In chapter 2 and chapter 3, we synthesized two series of alkylthio substituted MPc derivatives and successfully tuned Pc absorption in solution from ~680 nm to 850 nm. We also investigated thin film polymorphism and achieved Pc thin film photo response beyond 1000 nm. Pc materials have been used as dopants in P3HT/fullerene OPV devices for efficiency enhancement. In Chapter 3, we investigated the non-peripheral substituted Pcs as dopant in P3HT and utilized time-resolved microwave conductivity (TRMC) to probe free charge generation. For this series of Pcs, the free charge yield at the interface shows a clear trend of TiOPc > PbPc > H₂Pc, which can be correlated to (1) different metal species, (2) thermodynamic driving force of charge generation and (3) extent of Pc ring distortion. The charge transport behavior of Pc materials is highly dependent on long range organization of molecules, which is predominantly regulated by Pc π-π interactions. In chapter 4, we developed a new side-strapped Pc with 2-fold symmetry, which permits close π-π interaction along the substituent-absent axis and bears substituents on "side-straps" to ensure solubility. The substituent influence on Pc packing has been studied by UV-Vis spectroscopy in combination with single crystal XRD. We also investigated hole mobility of the Pc materials with conductive mode AFM (c-AFM) measurements and found that the side-strapped Pcs exhibit hole mobility up to 0.97 cm²V⁻¹s⁻¹, which is among the highest values recorded for solution processed Pc materials. Chapter 5 is a continuation of the work with side-strapped Pc. We explored the possibility of tuning side-strapped Pc energy levels to enable more diverse applications in organic electronics. We found alkoxy and alkylthio substitution on the non-peripheral positions effectively shifted frontier orbital levels and established a viable strategy to modulate optical and electronic properties of side-strapped Pcs. Chapter 6 summarizes the major discoveries in Chapter 2-5 and provides some future directions for current research may follow.
    Type
    text
    Electronic Dissertation
    Degree Name
    Ph.D.
    Degree Level
    doctoral
    Degree Program
    Graduate College
    Chemistry
    Degree Grantor
    University of Arizona
    Collections
    Dissertations

    entitlement

     
    The University of Arizona Libraries | 1510 E. University Blvd. | Tucson, AZ 85721-0055
    Tel 520-621-6442 | repository@u.library.arizona.edu
    DSpace software copyright © 2002-2017  DuraSpace
    Quick Guide | Contact Us | Send Feedback
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.