title: Efficient Exciton Diffusion and Resonance-Energy Transfer in Multilayered Organic Epitaxial Nanofibers.
abstract: Multilayered epitaxial nanofibers are exemplary model systems for the study of exciton dynamics and lasing in organic materials because of their well-defined morphology, high luminescence efficiencies, and color tunability. We use temperature-dependent continuous wave and picosecond photoluminescence (PL) spectroscopy to quantify exciton diffusion and resonance-energy transfer (RET) processes in multilayered nanofibers consisting of alternating layers of para-hexaphenyl (p6P) and α-sexithiophene (6T) serving as exciton donor and acceptor material, respectively. The high probability for RET processes is confirmed by quantum chemical calculations. The activation energy for exciton diffusion in p6P is determined to be as low as 19 meV, proving p6P epitaxial layers also as a very suitable donor material system. The small activation energy for exciton diffusion of the p6P donor material, the inferred high p6P-to-6T resonance-energy-transfer efficiency, and the observed weak PL temperature dependence of the 6T acceptor material together result in an exceptionally high optical emission performance of this all-organic material system, thus making it well suited, for example, for organic light-emitting devices.
authors.affiliation: NanoSYD, Mads Clausen Institute, University of Southern Denmark , Alsion 2, DK-6400 Sønderborg, Denmark.
authors.forename: Luciana
authors.initials: L
authors.lastname: Tavares
authors.affiliation: Department of Physics, University of Cagliari , Complesso Universitario di Monserrato, I-09042 Monserrato, Cagliari, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Cadelano
authors.affiliation: Department of Physics, University of Cagliari , Complesso Universitario di Monserrato, I-09042 Monserrato, Cagliari, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Quochi
authors.affiliation: Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz , A-4040 Linz, Austria ; Institute of Solid State Physics, University of Bremen , D-28359 Bremen, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Simbrunner
authors.affiliation: Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz , A-4040 Linz, Austria.
authors.forename: Günther
authors.initials: G
authors.lastname: Schwabegger
authors.affiliation: Department of Physics, University of Cagliari , Complesso Universitario di Monserrato, I-09042 Monserrato, Cagliari, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Saba
authors.affiliation: Department of Physics, University of Cagliari , Complesso Universitario di Monserrato, I-09042 Monserrato, Cagliari, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mura
authors.affiliation: Department of Physics, University of Cagliari , Complesso Universitario di Monserrato, I-09042 Monserrato, Cagliari, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bongiovanni
authors.affiliation: Institute of Physics, University of Brasilia , 04455, DF 70919-970 Brasília, Brazil.
authors.forename: Demétrio Antônio da Silva
authors.initials: DA
authors.lastname: Filho
authors.affiliation: Institute of Physics, University of Brasilia , 04455, DF 70919-970 Brasília, Brazil.
authors.forename: Wiliam Ferreira
authors.initials: WF
authors.lastname: da Cunha
authors.affiliation: NanoSYD, Mads Clausen Institute, University of Southern Denmark , Alsion 2, DK-6400 Sønderborg, Denmark.
authors.forename: Horst-Günter
authors.initials: HG
authors.lastname: Rubahn
authors.affiliation: NanoSYD, Mads Clausen Institute, University of Southern Denmark , Alsion 2, DK-6400 Sønderborg, Denmark.
authors.forename: Jakob
authors.initials: J
authors.lastname: Kjelstrup-Hansen