Intra- and interchain luminescence in amorphous and semicrystalline films of phenyl-substituted polythiophene

Ruseckas, Arvydas, Namdas, Ebinazar B., Ganguly, Tapan, Theander, Mathias, Svensson, Mattias, Andersson, Mats R., Inganas, Olle and Sundstrom, Villy (2001) Intra- and interchain luminescence in amorphous and semicrystalline films of phenyl-substituted polythiophene. Journal of Physical Chemistry B, 105 32: 7624-7631. doi:10.1021/jp010511n


Author Ruseckas, Arvydas
Namdas, Ebinazar B.
Ganguly, Tapan
Theander, Mathias
Svensson, Mattias
Andersson, Mats R.
Inganas, Olle
Sundstrom, Villy
Title Intra- and interchain luminescence in amorphous and semicrystalline films of phenyl-substituted polythiophene
Journal name Journal of Physical Chemistry B
ISSN 1089-5647
Publication date 2001-08-01
Year available 2001
Sub-type Article (original research)
DOI 10.1021/jp010511n
Open Access Status Not Open Access
Volume 105
Issue 32
Start page 7624
End page 7631
Total pages 8
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Abstract We report time-resolved photoluminescence (PL) measurements of spin-cast amorphous films of a regioregular polythiophene derivative poly[3-(4-octylphenyl)thiophene] and of annealed semicrystalline films of the same polymer with an interchain stacking distance of 5 Å. Red-shifted PL appears at long delay times in both pristine and annealed films, which we assign to interchain aggregates populated by excitation energy migration. Aggregate luminescence in annealed films exhibits a pronounced vibronic structure indicating the coupling to a C=C bond stretch with a Huang-Rhys factor S = 2. Two types of aggregates are distinguished in annealed films: In a few picoseconds most excitations are trapped by aggregates with a large energy gap (about 1.83 eV) between the lowest excited singlet state and the ground state. Excitation energy is transferred or the aggregates relax structurally with a time constant of about 200 ps to aggregates with a smaller energy gap (about 1.75 eV). The radiative lifetime of aggregates with smaller energy gap is estimated to be about 35 ns, two times longer than that of aggregates with the larger energy gap. In spin-cast amorphous films, emission from intrachain singlet excitons has a longer lifetime than in annealed films and only high-energy-gap aggregates are populated.
Keyword Chemistry, Physical
Chemistry
CHEMISTRY, PHYSICAL
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Mathematics and Physics
 
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Created: Wed, 09 Mar 2011, 23:18:58 EST