View Item 
      •   Home
      • 1. Schools
      • College of Engineering
      • School of Chemical and Biomedical Engineering (SCBE)
      • SCBE Research Reports (Staff & Graduate Students)
      • View Item
      •   Home
      • 1. Schools
      • College of Engineering
      • School of Chemical and Biomedical Engineering (SCBE)
      • SCBE Research Reports (Staff & Graduate Students)
      • View Item
      JavaScript is disabled for your browser. Some features of this site may not work without it.
      Subject Lookup

      Browse

      All of DR-NTUCommunities & CollectionsTitlesAuthorsBy DateSubjectsThis CollectionTitlesAuthorsBy DateSubjects

      My Account

      Login

      Statistics

      Most Popular ItemsStatistics by CountryMost Popular Authors

      About DR-NTU

      Characterization of fluorescent quantum dots via molecular modeling approach

      Thumbnail
      KwakSangKyu RG107-06 SCBE.pdf (254.8Kb)
      Author
      Kwak, Sang Kyu.
      Date of Issue
      2006
      School
      School of Chemical and Biomedical Engineering
      Abstract
      Unique characteristics of fluorescent materials have led to many applications in life, consequently, been subject to rigorous study as one-of-kind object in bio-imaging fields. However, as is the fast growing field, qualitative scheme of applications has been mainly sought with short of quantitative understanding. We resort to molecular simulation method in studying those respects. Our ultimate system of interest is a bi-metallic solid, CdSe, of which shape follows quantum dot such as colloidal particle in surfactant medium. To study the actual system, we adopt the model system of hard-sphere with point-charge to conduct the preliminary research, which involves application of correct Ewald-sum calculation. Upon finding a right passage to implement the Ewald-sum, different sizes of charged hard-spheres, which mimics CdSe, are to be investigated to collect qualitative figures of realistic system. This procedure is particularly important to reveal size and inner structures of quantum dots, which affect the fluorescence. We determine and compare the thermodynamic properties of mono-and divacancies in the face-centered-cubic and hexagonal-close-packed hard-sphere crystals via a modified grand-canonical ensemble. Widom-like particle insertion was employed to estimate the free energy of formation of mono-and divacancy and the results are supported by an alternative approach, which quantifies the entropy gain of the neighbor particles. In hcp crystal, we found a strong anisotropy in the orientational distribution of vacancies and observe an 8-fold increase in the number of divacancies in the hexagonal plane compared to the one in the out-of-plane at highest density of interest. This phenomenon is induced by the different arrangement and behavior of the shared nearest neighbor particles, which are located at the same distance from each vacant site in divacancy. The effect of divacancies on the free energy is to reduce that of the hcp crystal relative to the fcc by around 7×10-6kBT at melting.
      Subject
      DRNTU::Engineering::Chemical engineering::Biochemical engineering
      Type
      Research Report
      Collections
      • SCBE Research Reports (Staff & Graduate Students)

      Show full item record


      NTU Library, Nanyang Avenue, Singapore 639798 © 2011 Nanyang Technological University. All rights reserved.
      DSpace software copyright © 2002-2015  DuraSpace
      Contact Us | Send Feedback
      Share |    
      Theme by 
      Atmire NV
       

       


      NTU Library, Nanyang Avenue, Singapore 639798 © 2011 Nanyang Technological University. All rights reserved.
      DSpace software copyright © 2002-2015  DuraSpace
      Contact Us | Send Feedback
      Share |    
      Theme by 
      Atmire NV
       

       

      DCSIMG