Ultrafast conformational readjustment in hexamethylsexithiophene oligomer studied by femtosecond time-resolved photoluminescence

Kam Sing Wong; H. Wang; Guglielmo Lanzani

doi:10.1117/12.279271

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1 December 1997 Ultrafast conformational readjustment in hexamethylsexithiophene oligomer studied by femtosecond time-resolved photoluminescence

Kam Sing Wong, H. Wang, Guglielmo Lanzani

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Proceedings Volume 3145, Optical Probes of Conjugated Polymers; (1997) https://doi.org/10.1117/12.279271
Event: Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United States

Abstract

The ultrafast excited state dynamics of Hexamethylsexithiophene are investigated by femtosecond time-resolved photoluminescence. The spontaneous recombination lifetime of the singlet excited state is measured to be in the order of 400 ps. A photoluminescence (PL) risetime of approximately 1 ps and temporal spectra redshift is observed. These effects are attributed to planarization of the oligomer backbone in the excited state via vibrational and torsional relaxation which increases the effective conjugation length of the oligomer. The rapid vibrational and torsional relaxation gave rise to the PL risetime. The change in oligomer bandgap energy due to a longer effective conjugation length which is manifested in the transient spectral redshift.

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Kam Sing Wong, H. Wang, and Guglielmo Lanzani "Ultrafast conformational readjustment in hexamethylsexithiophene oligomer studied by femtosecond time-resolved photoluminescence", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997); https://doi.org/10.1117/12.279271

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