Luminescence decay of oriented phenylene nanofibers

Autor: Maria Teresa Neves-Petersen, Katharina Al-Shamery, R. Neuendorf, Horst-Günter Rubahn, Kasper Thilsing-Hansen, Steffen B. Petersen
Rok vydání: 2005
Předmět:
Zdroj: Thilsing-Hansen, K, Neves-Petersen, M T, Petersen, S B, Neuendorf, R, Al-Shamery, K & Rubahn, H-G 2005, ' Luminescence decay of oriented phenylene nanofibers ', Physical Review B, vol. 72, no. 11, pp. 115213-9 . https://doi.org/10.1103/PhysRevB.72.115213
Petersen, S B, Thilsing-Hansen, K, Neuendorf, R, Al-Shamery, K, Rubahn, H-G & Petersen, M T N 2005, ' Luminescence decay of oriented phenylene nanofibers ', Physical Review B. Condensed Matter and Materials Physics, vol. 72, no. 11, pp. 115213-.
ISSN: 1550-235X
1098-0121
DOI: 10.1103/physrevb.72.115213
Popis: The temporal decay of femtosecond UV light (266 nm) induced luminescence of arrays of hundreds of micrometers long organic nanofibers from phenylenes and substituted phenylenes with nanometric widths and heights is investigated. From a fit to the experimental curves monomolecular decay and exciton annihilation rate constants are determined. The excitonic lifetimes depend on the excitation power, the homogeneity of the fibers, and the environment\char22{}e.g., a dielectric coating of the nanofibers. In the limit of dense, quasicontinuous films lifetimes of the order of 800 ps are found, nearly independent of exact film thickness. For films made of well-oriented and well-separated aggregates the luminescence lifetimes are about a factor of 2 longer\char22{}i.e., approximately 2 ns. The observed luminescence spectra shift by $\ensuremath{\approx}7\phantom{\rule{0.3em}{0ex}}\mathrm{meV}∕\mathrm{ns}$ to the blue with increasing decay time but they do not degrade due to the crystalline perfection of the nanofibers. This temporal decay characteristic contrasts that found from previous measurements on nonoriented thin para-hexaphenylene films of laying molecules and points to the possibility of varying the temporal response of ultrathin organic films by forming oriented nanoaggregates.
Databáze: OpenAIRE
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