2026-09-19T22:55:00Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/396732022-01-13T07:54:21Zcom_1721.1_7582com_1721.1_7581col_1721.1_131022
Timothy M. Swager.
Satrijo, Andrew
Massachusetts Institute of Technology. Dept. of Chemistry.
Massachusetts Institute of Technology. Department of Chemistry
2007-12-07T15:26:03Z
2007-12-07T15:26:03Z
2007
2007
http://hdl.handle.net/1721.1/39673
181373941
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Vita.
Includes bibliographical references.
The semiconducting properties of conjugated polymers are finding use in various optoelectronic applications, including chemical sensors and light-emitting diodes. In this thesis, we investigate aggregation in conjugated polymers and how it affects the optical properties of these organic materials. We discuss how aggregation enhances exciton transport properties in fluorescent polymers, thereby increasing the probability of excitons reaching low-energy sites in the polymer. A consequence of this aggregation-enhanced exciton migration is that low-energy defect sites in a conjugated polymer can dramatically alter the polymer's fluorescence properties when it is in an aggregated state. In a poly(pphenylene ethynylene) (PPE) that was previously proposed to form green-emitting excimers, we found that a small concentration of anthryl defects in the polymer emitted green fluorescence that was only noticeable when the polymer was in an aggregated state (otherwise the polymer was fluorescent blue). After elucidating the origin of the green fluorescence, we purposely added more emissive anthryl units into the polymer to enhance the blue-to-green fluorescence color change that accompanied polymer aggregation.
(cont.) Using this anthryl-doped conjugated polymer, we developed aggregationbased chemical sensors that exhibited a visually noticeable fluorescence color change upon addition of poor solvents or biologically relevant, nonquenching, multicationic analytes (e.g., polyamines, neomycin) to the polymer solution. We also studied the effects of aggregation on the optical properties of a chiral poly(p-phenylene vinylene) (PPV) derivative in solutions and in films. We found that the organizations and functional properties existing in aggregated polymer solutions can be transferred to the film state by controlling the processing conditions. Using the same polymer, we were able to obtain films with different architectures and luminescence properties simply by adjusting the spin-casting solvent and film annealing conditions. Controlling the organizations and functional properties of conjugated polymer films is important in the fabrication of conjugated polymer-based optoelectronic devices.
by Andrew Satrijo.
Ph.D.
186 p.
eng
Massachusetts Institute of Technology
M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.
http://dspace.mit.edu/handle/1721.1/7582
Chemistry.
Controlling the architectures and optical properties of conjugated polymer aggregates and films
Thesis
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<Abstract>The semiconducting properties of conjugated polymers are finding use in various optoelectronic applications, including chemical sensors and light-emitting diodes. In this thesis, we investigate aggregation in conjugated polymers and how it affects the optical properties of these organic materials. We discuss how aggregation enhances exciton transport properties in fluorescent polymers, thereby increasing the probability of excitons reaching low-energy sites in the polymer. A consequence of this aggregation-enhanced exciton migration is that low-energy defect sites in a conjugated polymer can dramatically alter the polymer's fluorescence properties when it is in an aggregated state. In a poly(pphenylene ethynylene) (PPE) that was previously proposed to form green-emitting excimers, we found that a small concentration of anthryl defects in the polymer emitted green fluorescence that was only noticeable when the polymer was in an aggregated state (otherwise the polymer was fluorescent blue). After elucidating the origin of the green fluorescence, we purposely added more emissive anthryl units into the polymer to enhance the blue-to-green fluorescence color change that accompanied polymer aggregation.</Abstract>
<Abstract>(cont.) Using this anthryl-doped conjugated polymer, we developed aggregationbased chemical sensors that exhibited a visually noticeable fluorescence color change upon addition of poor solvents or biologically relevant, nonquenching, multicationic analytes (e.g., polyamines, neomycin) to the polymer solution. We also studied the effects of aggregation on the optical properties of a chiral poly(p-phenylene vinylene) (PPV) derivative in solutions and in films. We found that the organizations and functional properties existing in aggregated polymer solutions can be transferred to the film state by controlling the processing conditions. Using the same polymer, we were able to obtain films with different architectures and luminescence properties simply by adjusting the spin-casting solvent and film annealing conditions. Controlling the organizations and functional properties of conjugated polymer films is important in the fabrication of conjugated polymer-based optoelectronic devices.</Abstract>
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