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URN etd-0703115-163814
Author Guan-hung Lu
Author's Email Address No Public.
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Department Materials and Optoelectronic Science
Year 2014
Semester 2
Degree Master
Type of Document
Language English
Title Compatible Assemblies of PS-P2VP/Pyrene Derivatives with Tunable Bandgaps and Photoluminescent Emissions
Date of Defense 2015-07-08
Page Count 118
Keyword
  • block copolymer
  • pyrene
  • photoluminescence
  • H-bonding
  • photonic bandgap
  • lasing application
  • Abstract In this study, photonic reflectors with tunable photoluminescence (PL) emissions and photonic bandgaps are investigated in compatible assembles of the amphiphilic polystyrene-block-poly(2-vinylpyridine) (PS-P2VP) blended with various pyrene derivatives including 1-aminopyrene (Py-NH2), 1-methanolpyrene (Py-CH2OH) and 1-pyrenecarboxylic acid (Py-COOH). Various microphase-separated morphologies can be found in the as-spun PS-P2VP/pyrene derivative hybrid thin films with different quantities of the included pyrene derivatives denoted by γ value which is a molar ratio of the pyrene derivative to P2VP unit. The intermolecular interactions between the pyridines of P2VP and the specific functional groups of pyrene derivatives are investigated by Fourier transform infrared spectroscopy (FTIR). In PS-P2VP/Py-NH2, the absorbance of pyridine peaks at 991cm-1 and 1597 cm-1 shifts to high wavenumber, suggesting the H-bonding interaction. With the increase of the γ value, phase transitions from the intrinsic lamellar to bicontinuous and finally to spherical microstructures are found in PS-P2VP/Py-NH2 hybrid thin films. Meanwhile, the PL spectra show that the decreased monomeric emission and enhanced excimer emission. In contrast, the translation from the parallel lamellae to network morphologies is found in both PS-P2VP/Py-CH2OH and PS-P2VP/Py-COOH hybrid thin films as the γ value increases. As γ value is low, PL emissions of both PS-P2VP/Py-CH2OH and PS-P2VP/Py-COOH hybrids exhibit the coexistence of monomeric and excimer emissions. Notably, the excimer emission is composed of static and dynamic emissions. As γ value is high, the monomeric emission disappears and only excimer emission can be obtained. Moreover, the PL emission in the PS102-P2VP97/Py-CH2OH hybrids exhibit the rival for the static and dynamic excimer emissions varied with the γ value. In contrast, the PS-P2VP/Py-COOH hybrid thin films display that both static and dynamic excimer emissions grow up coincidently. After 1,1,2-trichloroethane (TCE) annealing, well-aligned parallel lamellae and order gyroid microstructures can be accomplished. The PL behavior, however, is almost similar to that without solvent annealing. Finally, we conduct the swelling and deswelling process by alcohols to successfully trap the photonic bandgaps (PBGs) in visible wavelength. After trapping the PBGs by methanol and ethanol, the almost identical band position for both PL excimer emission and PBG can be carried out in the PS-P2VP/Py-CH2OH with γ = 1/20, indicating the formation of the Bragg reflector capable of lasing applications.
    Advisory Committee
  • Rong-Ming Ho - chair
  • Ya-Sen Sun - co-chair
  • Jin-Long Hong - co-chair
  • Jing-Cherng Tsai - co-chair
  • Shiao-Wei Kuo - co-chair
  • Yeo-Wan Chiang - advisor
  • Files
  • etd-0703115-163814.pdf
  • Indicate in-campus at 5 year and off-campus access at 5 year.
    Date of Submission 2015-08-04

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