The photophysics of luminescence in multilayered organic nanofibers

Luciana Tavares, Francesco Quochi, Clemens Simbrunner, Günther Schwabegger, Horst-Günter Rubahn, Jakob Kjelstrup-Hansen

Publikation: Konferencebidrag uden forlag/tidsskriftPosterForskning

Resumé

Periodic deposition of para-hexaphenyl (p6P) and alfa-sexithiophene (6T) molecules on a muscovite mica substrate by hot wall epitaxy results in multilayered, crystalline nanofibers. By varying the relative thicknesses of the constituent materials, the fluorescence spectrum can be tuned within the red, green, and blue spectral range [1, 2]. Illumination of the multilayered nanofiber sample with UV light (3.8 eV photon energy) directly excites fluorescence from the p6P layers, while the 6T layers emit light due to sensitization from the excited p6P [2]. Illumination with blue light (2.5 eV photon energy), which is below the optical gap of p6P, excites photoluminescence (PL) only from the 6T layers [3]. Here, we probe the energy transfer and exciton recombination characteristics by temperature dependent PL spectroscopy using either 3.8 eV or 2.5 eV photons for stimulating the p6P or 6T layers, respectively. While the p6P quantum yield decreases by an order of magnitude between 6 K and 293 K, the 6T monolayer emission exhibits much weaker temperature dependence. We tentatively attribute this to the fact that crystalline p6P layers are H aggregates while the ultrathin 6T layers have a radically different aggregation state (most presumably J aggregates). The ratio between emission intensity of the sensitized and directly excited 6T monolayer increases by around 40% when increasing the temperature from 6 K to 293 K due to enhanced energy transfer from p6P to the 6T monolayer. To further elucidate the exciton dynamics, we have used temperature-dependent, time-resolved PL spectroscopy that can provide quantitative data on the exciton diffusion and energy transfer processes. This improved understanding of the photophysics in organic heterocrystals can aid in the development of new nanomaterials with desired optical properties.

1 C. Simbrunner et al. ACS Nano 4, 6244 (2010)
2 C. Simbrunner et al. ACS Nano 6, 4629 (2012)
3 F. Quochi et al. Adv. Opt. Mat. 1, 117 (2013)

OriginalsprogEngelsk
Publikationsdato13. nov. 2014
StatusUdgivet - 13. nov. 2014
BegivenhedAnnual Meeting 2014 for the Danish Optical Society - , Danmark
Varighed: 13. nov. 2014 → …

Konference

KonferenceAnnual Meeting 2014 for the Danish Optical Society
LandDanmark
Periode13/11/2014 → …

Fingeraftryk

luminescence
energy transfer
excitons
photoluminescence
photons
illumination
fluorescence
muscovite
mica
epitaxy
spectroscopy
temperature
temperature dependence
energy
probes
molecules

Citer dette

Tavares, L., Quochi, F., Simbrunner, C., Schwabegger, G., Rubahn, H-G., & Kjelstrup-Hansen, J. (2014). The photophysics of luminescence in multilayered organic nanofibers. Poster session præsenteret på Annual Meeting 2014 for the Danish Optical Society , Danmark.
Tavares, Luciana ; Quochi, Francesco ; Simbrunner, Clemens ; Schwabegger, Günther ; Rubahn, Horst-Günter ; Kjelstrup-Hansen, Jakob. / The photophysics of luminescence in multilayered organic nanofibers. Poster session præsenteret på Annual Meeting 2014 for the Danish Optical Society , Danmark.
@conference{59a2dd200d564abfbe9efe6a0eff248e,
title = "The photophysics of luminescence in multilayered organic nanofibers",
abstract = "Periodic deposition of para-hexaphenyl (p6P) and alfa-sexithiophene (6T) molecules on a muscovite mica substrate by hot wall epitaxy results in multilayered, crystalline nanofibers. By varying the relative thicknesses of the constituent materials, the fluorescence spectrum can be tuned within the red, green, and blue spectral range [1, 2]. Illumination of the multilayered nanofiber sample with UV light (3.8 eV photon energy) directly excites fluorescence from the p6P layers, while the 6T layers emit light due to sensitization from the excited p6P [2]. Illumination with blue light (2.5 eV photon energy), which is below the optical gap of p6P, excites photoluminescence (PL) only from the 6T layers [3]. Here, we probe the energy transfer and exciton recombination characteristics by temperature dependent PL spectroscopy using either 3.8 eV or 2.5 eV photons for stimulating the p6P or 6T layers, respectively. While the p6P quantum yield decreases by an order of magnitude between 6 K and 293 K, the 6T monolayer emission exhibits much weaker temperature dependence. We tentatively attribute this to the fact that crystalline p6P layers are H aggregates while the ultrathin 6T layers have a radically different aggregation state (most presumably J aggregates). The ratio between emission intensity of the sensitized and directly excited 6T monolayer increases by around 40{\%} when increasing the temperature from 6 K to 293 K due to enhanced energy transfer from p6P to the 6T monolayer. To further elucidate the exciton dynamics, we have used temperature-dependent, time-resolved PL spectroscopy that can provide quantitative data on the exciton diffusion and energy transfer processes. This improved understanding of the photophysics in organic heterocrystals can aid in the development of new nanomaterials with desired optical properties.1 C. Simbrunner et al. ACS Nano 4, 6244 (2010)2 C. Simbrunner et al. ACS Nano 6, 4629 (2012)3 F. Quochi et al. Adv. Opt. Mat. 1, 117 (2013)",
author = "Luciana Tavares and Francesco Quochi and Clemens Simbrunner and G{\"u}nther Schwabegger and Horst-G{\"u}nter Rubahn and Jakob Kjelstrup-Hansen",
year = "2014",
month = "11",
day = "13",
language = "English",
note = "Annual Meeting 2014 for the Danish Optical Society , DOPS ; Conference date: 13-11-2014",

}

Tavares, L, Quochi, F, Simbrunner, C, Schwabegger, G, Rubahn, H-G & Kjelstrup-Hansen, J 2014, 'The photophysics of luminescence in multilayered organic nanofibers', Annual Meeting 2014 for the Danish Optical Society , Danmark, 13/11/2014.

The photophysics of luminescence in multilayered organic nanofibers. / Tavares, Luciana ; Quochi, Francesco; Simbrunner, Clemens; Schwabegger, Günther ; Rubahn, Horst-Günter; Kjelstrup-Hansen, Jakob.

2014. Poster session præsenteret på Annual Meeting 2014 for the Danish Optical Society , Danmark.

Publikation: Konferencebidrag uden forlag/tidsskriftPosterForskning

TY - CONF

T1 - The photophysics of luminescence in multilayered organic nanofibers

AU - Tavares, Luciana

AU - Quochi, Francesco

AU - Simbrunner, Clemens

AU - Schwabegger, Günther

AU - Rubahn, Horst-Günter

AU - Kjelstrup-Hansen, Jakob

PY - 2014/11/13

Y1 - 2014/11/13

N2 - Periodic deposition of para-hexaphenyl (p6P) and alfa-sexithiophene (6T) molecules on a muscovite mica substrate by hot wall epitaxy results in multilayered, crystalline nanofibers. By varying the relative thicknesses of the constituent materials, the fluorescence spectrum can be tuned within the red, green, and blue spectral range [1, 2]. Illumination of the multilayered nanofiber sample with UV light (3.8 eV photon energy) directly excites fluorescence from the p6P layers, while the 6T layers emit light due to sensitization from the excited p6P [2]. Illumination with blue light (2.5 eV photon energy), which is below the optical gap of p6P, excites photoluminescence (PL) only from the 6T layers [3]. Here, we probe the energy transfer and exciton recombination characteristics by temperature dependent PL spectroscopy using either 3.8 eV or 2.5 eV photons for stimulating the p6P or 6T layers, respectively. While the p6P quantum yield decreases by an order of magnitude between 6 K and 293 K, the 6T monolayer emission exhibits much weaker temperature dependence. We tentatively attribute this to the fact that crystalline p6P layers are H aggregates while the ultrathin 6T layers have a radically different aggregation state (most presumably J aggregates). The ratio between emission intensity of the sensitized and directly excited 6T monolayer increases by around 40% when increasing the temperature from 6 K to 293 K due to enhanced energy transfer from p6P to the 6T monolayer. To further elucidate the exciton dynamics, we have used temperature-dependent, time-resolved PL spectroscopy that can provide quantitative data on the exciton diffusion and energy transfer processes. This improved understanding of the photophysics in organic heterocrystals can aid in the development of new nanomaterials with desired optical properties.1 C. Simbrunner et al. ACS Nano 4, 6244 (2010)2 C. Simbrunner et al. ACS Nano 6, 4629 (2012)3 F. Quochi et al. Adv. Opt. Mat. 1, 117 (2013)

AB - Periodic deposition of para-hexaphenyl (p6P) and alfa-sexithiophene (6T) molecules on a muscovite mica substrate by hot wall epitaxy results in multilayered, crystalline nanofibers. By varying the relative thicknesses of the constituent materials, the fluorescence spectrum can be tuned within the red, green, and blue spectral range [1, 2]. Illumination of the multilayered nanofiber sample with UV light (3.8 eV photon energy) directly excites fluorescence from the p6P layers, while the 6T layers emit light due to sensitization from the excited p6P [2]. Illumination with blue light (2.5 eV photon energy), which is below the optical gap of p6P, excites photoluminescence (PL) only from the 6T layers [3]. Here, we probe the energy transfer and exciton recombination characteristics by temperature dependent PL spectroscopy using either 3.8 eV or 2.5 eV photons for stimulating the p6P or 6T layers, respectively. While the p6P quantum yield decreases by an order of magnitude between 6 K and 293 K, the 6T monolayer emission exhibits much weaker temperature dependence. We tentatively attribute this to the fact that crystalline p6P layers are H aggregates while the ultrathin 6T layers have a radically different aggregation state (most presumably J aggregates). The ratio between emission intensity of the sensitized and directly excited 6T monolayer increases by around 40% when increasing the temperature from 6 K to 293 K due to enhanced energy transfer from p6P to the 6T monolayer. To further elucidate the exciton dynamics, we have used temperature-dependent, time-resolved PL spectroscopy that can provide quantitative data on the exciton diffusion and energy transfer processes. This improved understanding of the photophysics in organic heterocrystals can aid in the development of new nanomaterials with desired optical properties.1 C. Simbrunner et al. ACS Nano 4, 6244 (2010)2 C. Simbrunner et al. ACS Nano 6, 4629 (2012)3 F. Quochi et al. Adv. Opt. Mat. 1, 117 (2013)

M3 - Poster

ER -

Tavares L, Quochi F, Simbrunner C, Schwabegger G, Rubahn H-G, Kjelstrup-Hansen J. The photophysics of luminescence in multilayered organic nanofibers. 2014. Poster session præsenteret på Annual Meeting 2014 for the Danish Optical Society , Danmark.