Molecular Packing Effects on the Optical Spectra and Triplet Dynamics in Oligofluorene Films

Cabanillas‐González, Juan; Sciascia, Calogero; Lanzani, Guglielmo; Toffanin, Stefano; Capelli, Raffaella; Ramón, Miguel Calvo; Muccini, Michele; Gierschner, Johannes; Hwu, Tsyr-Yuan; Wong, Ken‐Tsung

doi:10.1021/jp8044143

Cited by 19 publications

(13 citation statements)

References 41 publications

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“…A bi‐exponential fit of PP kinetics provides lifetimes of τ 1 = 5 ps and τ 2 ≥ 650 ps with statistical weights of 6% and 94% respectively, thus showing that fs‐ps deactivation by annihilation plays no significant role on Rtx dynamics. The lack of fast deactivation is explained by the backbone encapsulation in Rtx since enhanced chain separation leads to a reduction in exciton‐exciton annihilation which in turn is usually important in densely packed solid‐state samples 22, 23. Likewise, chain separation prevents partial stabilization of inter‐chain polaron pairs and, in consequence, formation of the triplet excitons from charge recombination.…”

Section: Methodsmentioning

confidence: 99%

Amplified Spontaneous Emission in Conjugated Polyrotaxanes Under Quasi‐cw Pumping

et al. 2013

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Amplified spontaneous emission under millisecond pulsed excitation on a rotaxane-insulated conjugated polymer is reported. Pump-probe spectroscopy confirms the absence of polaron-pair absorption in the gain spectral region as the main factor contributing to quasi-steady-state amplified spontaneous emission. The low polaron-pair yield in this compound is the likely result of effective backbone encapsulation provided by the threading ring.

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Section: Methodsmentioning

confidence: 99%

Amplified Spontaneous Emission in Conjugated Polyrotaxanes Under Quasi‐cw Pumping

et al. 2013

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“…Their typical decay times are however too slow to be covered by the limited dynamical range of pump-probe experiments. [30][31][32] …”

Section: Physical Meaning Of Pump-probe Signalmentioning

confidence: 99%

Pump‐Probe Spectroscopy in Organic Semiconductors: Monitoring Fundamental Processes of Relevance in Optoelectronics

2011

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In this review we highlight the contribution of pump-probe spectroscopy to understand elementary processes taking place in organic based optoelectronic devices. The techniques described in this article span from conventional pump-probe spectroscopy to electromodulated pump-probe and the state-of-the-art confocal pump-probe microscopy. The article is structured according to three fundamental processes (optical gain, charge photogeneration and charge transport) and the contribution of these techniques on them. The combination of these tools opens up new perspectives for assessing the role of short-lived excited states on processes lying underneath organic device operation.

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“…This behavior is favored by the conformational flexibility of the compounds containing carbazole (L13) or phenylamine (L78) aromatic units connected by vinyl segments. This molecular structure assures the delocalization and superposition of the molecular orbitals and determines the electronic intra-molecular interactions and strong polarization interactions with the surrounding molecules [63]. The peaks situated around 640 nm and 720 nm in the UV-Vis spectra of the heterostructures realized with ZnPc arise from the π-π* transitions in the phthalocyanine macrocycle.…”

Section: Resultsmentioning

confidence: 95%

Arylenevinylene Oligomer-Based Heterostructures on Flexible AZO Electrodes

et al. 2021

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We investigated the optical and electrical properties of flexible single and bi-layer organic heterostructures prepared by vacuum evaporation with a p-type layer of arylenevinylene oligomers, based on carbazole, 3,3′ bis(N hexylcarbazole)vinylbenzene = L13, or triphenylamine, 1,4 bis [4 (N,N’ diphenylamino)phenylvinyl] benzene = L78, and an n-type layer of 5,10,15,20-tetra(4-pyrydil)21H,23H-porphyne = TPyP. Transparent conductor films of Al-doped ZnO (AZO) with high transparency, >90% for wavelengths >400 nm, and low resistivity, between 6.9 × 10−4 Ω·cm and 23 × 10−4 Ω·cm, were deposited by pulsed laser deposition on flexible substrates of polyethylene terephthalate (PET). The properties of the heterostructures based on oligomers and zinc phthalocyanine (ZnPc) were compared, emphasizing the effect of the surface morphology. The measurements revealed a good absorption in the visible range of the PET/AZO/arylenevinylene oligomer/TPyP heterostructures and a typical injection contact behavior with linear (ZnPc, L78) or non-linear (L13) J-V characteristics in the dark, at voltages <0.4 V. The heterostructure PET/AZO/L78/TPyP/Al showed a current density of ~1 mA/cm2 at a voltage of 0.3 V. The correlation between the roughness exponent, evaluated from the height-height correlation function, grain shape, and electrical behavior was analyzed. Consequently, the oligomer based on triphenylamine could be a promising replacement of donor ZnPc in flexible electronic applications.

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Molecular Packing Effects on the Optical Spectra and Triplet Dynamics in Oligofluorene Films

Cited by 19 publications

References 41 publications

Amplified Spontaneous Emission in Conjugated Polyrotaxanes Under Quasi‐cw Pumping

Amplified Spontaneous Emission in Conjugated Polyrotaxanes Under Quasi‐cw Pumping

Pump‐Probe Spectroscopy in Organic Semiconductors: Monitoring Fundamental Processes of Relevance in Optoelectronics

Arylenevinylene Oligomer-Based Heterostructures on Flexible AZO Electrodes

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