| 1. |
- Chekalin, S, et al.
(author)
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Femtosecond pump–probe investigation of primary photoinduced processes in C60–Sn nanostructures
- 2003
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In: Synthetic Metals. - 0379-6779. ; 139:3, s. 799-802
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Journal article (peer-reviewed)abstract
- Investigation of photoinduced processes in different C60–Sn nanostructures excited by 150 fs laser pulses at 400 nm (109 W/cm2) was performed with femtosecond supercontinuum probing of difference absorption and reflection in the spectral range of 400–1600 nm. The dynamics of relaxation are quite different for various nanostructures depending on the deposition mode and the ratio of tin and fullerene content. Non-monotonic relaxation, observed in the samples with Sn nanocrystallites, is explained by electron exchange between C60 and the metal.
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| 2. |
- Gulbinas, V, et al.
(author)
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Charge carrier photogeneration in conjugated polymer
- 2002
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In: Ultrafast phenomena in semiconductors 2001 / Material Science Forum. - 0255-5476. - 0878498907 - 9780878498901 ; 384-385, s. 279-286
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Conference paper (peer-reviewed)abstract
- The electric field-assisted charge carrier photogeneration in a Ladder-Type Methyl substituted Poly(Para-Phenylene) was investigated by studying the electromodulated ultrafast transient differential absorption spectra and kinetics. The field stimulated appearance of the polaron absorption and quenching of the singlet exciton absorption proves that dissociation of excitons into geminately bound electron-hole pairs occurs within the entire exciton lifetime and proceeds from the relaxed state. An influence of the optically created excitons and charge pairs on the Stark-shift of the absorption band was observed and interpreted as caused by the modification of the dielectric constant of the medium. The initial separation distance of the charge carriers and its evolution in time were determined from the Stark-shift dynamics. The initial separation distance was obtained being slightly larger than the distance between adjacent polymer chains.
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| 3. |
- Gulbinas, V, et al.
(author)
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Dynamics of charge pair generation in ladder-type poly(para-phenylene) at different excitation photon energies
- 2004
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In: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 70:3, s. 1-035215
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Journal article (peer-reviewed)abstract
- Generation of charge pairs in a ladder-type poly(para-phenylene) was investigated by means of electric field modulated femtosecond pump-probe absorption spectroscopy upon excitation at 3.1 and 4.66 eV. Exciting at 3.1 eV in the optical S-0-->S-1 transition, the number of geminately bound electron-hole pairs rises smoothly within the entire exciton life time. Upon excitation at 4.66 eV an instantaneous generation of geminate pairs superimposed on the more gradual increase is observed. Both processes are field-assisted, albeit differently. The former is attributed to ultrafast dissociation of a hot Franck-Condon state, while the latter is assigned to dissociation of vibrationally relaxed singlet excitons.
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| 5. |
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| 6. |
- Zausjitsyn, Yuri, et al.
(author)
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Ultrafast light-induced charge pair formation dynamics in poly[3-(2'-methoxy-5' octylphenyl)thiophene]
- 2004
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 70:7
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Journal article (peer-reviewed)abstract
- Charge pair photogeneration was investigated by ultrafast absorption spectroscopy for different excitation photon energies in poly[3-(2'- methoxy-5' octylphenyl)thiophene] (POMeOPT) film with and without an external electric field. Electric field-assisted charge pair photogeneration in POMeOPT occurs from vibrationally relaxed singlet excitons during their entire lifetime and charge pair formation takes place in this manner even in the absence of an external electric field. From our data there are no indications of hot exciton dissociation to charge pairs even when a large amount of excess energy is supplied to the excitons. To explain these observations we present a model with energy transfer to low-barrier dissociation sites as a key feature.
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