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Autori principali: Naeimi, Moha, Völzer, Tim, Lange, Regina, Oldenburg, Kevin, Lochbrunner, Stefan, Barke, Ingo, Speller, Sylvia
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2507.21294
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author Naeimi, Moha
Völzer, Tim
Lange, Regina
Oldenburg, Kevin
Lochbrunner, Stefan
Barke, Ingo
Speller, Sylvia
author_facet Naeimi, Moha
Völzer, Tim
Lange, Regina
Oldenburg, Kevin
Lochbrunner, Stefan
Barke, Ingo
Speller, Sylvia
contents Among the organic semiconductors, rubrene stands out in terms of hole mobility, luminescence yield and exciton migration distance. A novel type of rubrene microcrystal is prepared in the orthorhombic phase, exhibiting zone-sectored tabular domains with distinct photoluminescence (PL) characteristics. These sectors exhibit distinct PL spectra and time-evolution, arising from differences in the in-plane orientation of the orthorhombic unit cell relative to the crystal surface. A combination of polarised optical microscopy, fluorescence lifetime imaging microscopy (FLIM), and atomic force microscopy (AFM) is used to characterise the samples in terms of crystal orientation, fluorescence lifetime, and photoluminescence spectra. Spatially resolved PL spectroscopy reveals that the redshifted 650 nm emission band has polarisation along the transition dipole moment and is associated with high photon absorption due to the alignment of excitation polarisation and transition dipole moment and selectively localized within specific sectors of the crystal. The detected photon originates from direct emission of a geminate coherent triplet pair, or from its fusion. This band exhibits pure mono-exponential dynamics with 3.7 ns lifetime. The triplet fusion behaviour in the succeeding time regimes can be treated in the framework of power law scaling and random walk. The emission kinetics are modelled using rate equations describing geminate and non-geminate exciton fusion processes, enabling a quantitative interpretation of the spatially resolved PL kinetics. These findings introduce a material-based strategy, opening novel routes for photonic applications and light harvesting.
format Preprint
id arxiv_https___arxiv_org_abs_2507_21294
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Zone-sectored organic crystals with spatially resolved exciton dynamics
Naeimi, Moha
Völzer, Tim
Lange, Regina
Oldenburg, Kevin
Lochbrunner, Stefan
Barke, Ingo
Speller, Sylvia
Optics
Materials Science
Among the organic semiconductors, rubrene stands out in terms of hole mobility, luminescence yield and exciton migration distance. A novel type of rubrene microcrystal is prepared in the orthorhombic phase, exhibiting zone-sectored tabular domains with distinct photoluminescence (PL) characteristics. These sectors exhibit distinct PL spectra and time-evolution, arising from differences in the in-plane orientation of the orthorhombic unit cell relative to the crystal surface. A combination of polarised optical microscopy, fluorescence lifetime imaging microscopy (FLIM), and atomic force microscopy (AFM) is used to characterise the samples in terms of crystal orientation, fluorescence lifetime, and photoluminescence spectra. Spatially resolved PL spectroscopy reveals that the redshifted 650 nm emission band has polarisation along the transition dipole moment and is associated with high photon absorption due to the alignment of excitation polarisation and transition dipole moment and selectively localized within specific sectors of the crystal. The detected photon originates from direct emission of a geminate coherent triplet pair, or from its fusion. This band exhibits pure mono-exponential dynamics with 3.7 ns lifetime. The triplet fusion behaviour in the succeeding time regimes can be treated in the framework of power law scaling and random walk. The emission kinetics are modelled using rate equations describing geminate and non-geminate exciton fusion processes, enabling a quantitative interpretation of the spatially resolved PL kinetics. These findings introduce a material-based strategy, opening novel routes for photonic applications and light harvesting.
title Zone-sectored organic crystals with spatially resolved exciton dynamics
topic Optics
Materials Science
url https://arxiv.org/abs/2507.21294