Please use this identifier to cite or link to this item:
https://hdl.handle.net/10316/10260
Title: | Spectral and Photophysical Studies of Poly[2,6-(1,5-dioctylnaphthalene)]thiophenes | Authors: | Pina, J. Melo, J. Seixas de Burrows, H. D. Galbrecht, F. Nehls, B. S. Farrell, T. Scherf, U. |
Issue Date: | 17-May-2007 | Publisher: | American Chemical Society | Citation: | The Journal of Physical Chemistry C. 111:19 (2007) 7185-7191 | Abstract: | A complete spectroscopic and photophysical study of three alternating naphthalene-α-thiophene copolymers was undertaken in solution (room and low temperature) and in the solid state (thin films in a Zeonex matrix). The study comprises absorption, emission, and triplet−triplet spectra together with quantitative measurements of quantum yield (fluorescence, intersystem-crossing, internal conversion, and singlet oxygen formation) lifetimes and singlet and triplet energies. The overall data allow the determination of the rate constants for all the decay processes. Comparison between the behavior of analogous 1-naphthyl(oligo)thiophenes and the 2,6-naphthalene(oligo)thiophene copolymers allows several important observations. First, the polymers display higher fluorescence quantum yields and lower S1→T1 intersystem-crossing yields than the oligomers. This can be attributed to the presence of the 1,5-dioctyloxynaphthalene groups in the copolymers leading to a more rigid polymer backbone, which decreases radiationless deactivation and increases the radiative efficiency. Second, the singlet and triplet energies are significantly lower in the polymers than with the corresponding oligomers. This implies a lower HOMO−LUMO energy difference in the polymers due to an extended π-delocalization. Third, the singlet-to-triplet (S1−T1) energy splitting is higher in the oligomers than with the polymers, even though the former display higher intersystem-crossing yields. It is suggested that this may result from intersystem-crossing in the oligomers involving significant charge-transfer (CT) character (spin-orbit coupling is mediated by CT mixing involving the singlet and triplet states in matrix elements of the type 1ΨCT |H‘|3Ψ1) of the relevant excited states but that is less important with the polymers. We believe that this may be relevant to understanding the nature of CT states in conjugated copolymers. | URI: | https://hdl.handle.net/10316/10260 | ISSN: | 1932-7447 | DOI: | 10.1021/jp070691m | Rights: | openAccess |
Appears in Collections: | FCTUC Química - Artigos em Revistas Internacionais |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
Spectral and Photophysical Studies of Poly.pdf | 213.22 kB | Adobe PDF | View/Open |
SCOPUSTM
Citations
11
checked on Oct 14, 2024
WEB OF SCIENCETM
Citations
10
10
checked on Oct 2, 2024
Page view(s) 50
475
checked on Oct 8, 2024
Download(s) 50
805
checked on Oct 8, 2024
Google ScholarTM
Check
Altmetric
Altmetric
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.