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Femtosecond Pump and Probe Spectroscopy on Poly(Para-Phenylenes)

Published online by Cambridge University Press:  10 February 2011

W. Graupner
Affiliation:
Institut für Festkörperphysik, Technische Universität Graz, A-8010 Graz, Austria
G. Cerullo
Affiliation:
CEQSE - C.N.R., Dipartimento di Fisica, Politecnico, 1-20133 Milano, Italy
G. Kranzelbinder
Affiliation:
Institut für Festkörperphysik, Technische Universität Graz, A-8010 Graz, Austria
G. Lanzani
Affiliation:
Istituto di Matematica e Fisica, Universita di Sassari, 1-07100 Sassari, Italy
S. Stagira
Affiliation:
CEQSE - C.N.R., Dipartimento di Fisica, Politecnico, 1-20133 Milano, Italy
M. Nisoli
Affiliation:
CEQSE - C.N.R., Dipartimento di Fisica, Politecnico, 1-20133 Milano, Italy
S. De Silvestri
Affiliation:
CEQSE - C.N.R., Dipartimento di Fisica, Politecnico, 1-20133 Milano, Italy
G. Leising
Affiliation:
Institut für Festkörperphysik, Technische Universität Graz, A-8010 Graz, Austria
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Abstract

We studied the sub-picosecond dynamics of photoexcitations in methyl-substituted poly(para--phenylene)-type ladder polymer (m-LPPP) films in a wide excitation density range up to values typical for the regime of narrow band emission by pump-probe spectroscopy. The singlet excitons relaxation dynamics, monitored at the stimulated emission (SE) peak at 2.53 eV, showed an intensity dependent ultrafast decay component, which occurs on a sub-picosecond time scale, ascribed to the onset of amplified spontaneous emission (ASE). In addition we identified photoinduced absorption (PA) bands of singlet excitons at 1.48 eV and polarons at 1.9 eV respectively. At high excitation density an additional absorption band becomes evident at 2.63 eV.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

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