rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Effect of Surface Environment on Energy Relaxation Dynamics in Photo-Excited Nanocrystals
  name:
    name part: Maiti, Sourav
    role:
      role term: creator
    role:
      role term: author.
  name:
    name part: Son, Dong
    role:
      role term: thesis advisor.
  name:
    name part: Texas A & M University
    role:
      role term: degree granting institution.
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: txu
    date issued: 2014
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: remote
    extent: 1 online resource.
  abstract: The optical properties of semiconducting nanocrystals have considerable application in various fields such as biological imaging, light emitting devices and solar cells. Due to high surface to volume ratio surface structure has a profound effect on the exciton quantum yield and charge carrier dynamics of these nanocrystals. Surface imperfections or surface defects often decrease the exciton quantum yield by trapping the charge carriers and thus affect relaxation dynamics. Surface binding surfactants play an important role in determining optical properties and exciton dynamics as they can remove surface defects through passivation and they can also introduce new trap sites. Transition metal doped semiconducting nanocrystals especially Mn-doped in II-VI semiconducting host show stoke shifted Mn-emission with high Mn-emission quantum yield applicable in light emitting devices, biological imaging and sensors. Although Mn-emission was found to depend on surface effects, the underlying mechanism and dynamics was not explored in great detail. Thiols are important class of surfactants used to passivate nanocrystals especially to make water soluble nanocrystals. Thiols are hole trapping surfactants and known to quench the emission in CdSe or CdS nanocrytals. In our study, we examined the effect of hole trapping ligand octanethiol on the Mn-luminescence quantum yield and exciton dynamics in Mn-doped CdS/ZnS nanocrystals. Surprisingly Mn-luminescence quantum yield was found to increase in presence of octanethiol in contrary to undoped nanocrystals where octanethiol almost quenched the exciton emission. Combining transient absorption measurements with steady state Mn-photoluminescence and Mn-lifetime measurements, we confirmed the existence of an energy transfer process from octanethiol created hole traps to Mn that enhances the Mn-photoluminescence. Apart from studying the effect of surface environment in exciton relaxation dynamics in Mn-doped nanocrystals, we have studied th…
  note: by Sourav Maiti.
  note: "Major Subject: Chemistry"
  note: Includes vita.
  note: Master of Science Texas A & M University 2013 http://hdl.handle.net/1969.1/151636
  note: Includes bibliographical references.
  note: Text (Thesis)
  subject:
    topic: Major Chemistry
  subject:
    topic: Mn-doped nanocrystals
  subject:
    topic: energy transfer
  subject:
    topic: Mn-luminescence
  subject:
    topic: trapping
  subject:
    topic: thiol
  subject:
    topic: magnetic nanocrystals
  subject:
    topic: spin-lattice relaxation
  identifier: http://hdl.handle.net/1969.1/151636
  record info:
    record content source: TXA
    record creation date: 140623
    record change date: 20151206101826.0
    record identifier: in00003463272
    language of cataloging:
      language term: eng