Photoluminescent energy transfer from poly(phenyleneethylene)s to a series of dyes

Photoluminescent energy transfer in conjugated polymer-dye blend films was studied by means of steady-state fluorescence spectroscopy in order to identify efficient energy acceptors with red-shifted emissions relative to donor emission. A dialkoxy substituted poly(phenylene- ethylene) (PPE) and its pentiptycene derivative were used as the energy donor, and xanthene, cyanine, phenoxazine, and squaraine dyes were utilized as energy acceptors. Energy transfer efficiency was investigated by exciting the polymer and monitoring the quenching of polymer emission, along with the enhanced dye emission. Squaraine dyes exhibited up to 110 times greater emission than the intrinsic dye emission, even though they have little spectral overlap with the polymer donor. Moreover, even after normalization for the degree of spectral overlap, the sensitized emission intensity of squaraine was unusually high relative to those of the other dyes. This result suggested that an alternative Dexter mechanism substantially contributes to efficient energy transfer beyond the "through-space" dipolar mechanism of the Forster theory. This process is additionally assisted by the internal free volume within specific polymer hosts that prevent phase separation and self-aggregation of dyes, as well as preserving the dye emissive within the interstitial cavity.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Song, Inja, S.M. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Timothy M. Swager.

• Chemistry.

Statement dc:rights

• 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.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/38522

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/38522