Molecular Chromophore-DNA Architectures With Fullerenes: Optical Properties and Solar Cells

Supramolecular chemistry allows the construction of complex molecular architectures and the design of collective photophysical properties. DNA is an attractive template to build such supramolecular architectures due to its helical structure, the defined distances between the bases and the canonical base pairing that results in precise control of the chromophore position. The tailored properties of DNA-templated supramolecules eventually allow their implementation into optoelectronic applications. For the generation of free charge carriers from photo-generated excitons, fullerenes can be utilized. We synthesized two fullerene derivates, one of which binds by electrostatic interactions to single-stranded DNA, while the other contains two 2′-deoxyuridine moieties and assembles specifically along oligo-2′-deoxyadenosines (dA20) as DNA template. The DNA-directed assembly of both fullerenes in aqueous solution was investigated by UV/Vis absorbance and circular dichroism (CD) spectroscopy. The specific interactions with DNA make fullerenes with the 2′-deoxyuridine moieties a significantly better component for supramolecular DNA architectures. We studied the fluorescence quenching of both fullerenes with a DNA chromophore assembly. To investigate one of the key properties for optoelectronic applications, that is the supramolecular structure of the DNA-based assemblies in the solid phase, we characterized the CD of supramolecular chromophore-DNA architectures in thin films. Remarkably, the helical chirality of the chromophore assemblies that is induced by the DNA template is conserved even in the solid state. Upon implementation into organic solar cells, the external quantum efficiency measurements showed charge carrier generation on all three chromophore components of the DNA assemblies. The fullerenes with the 2′-deoxyuridine moieties enhance the quantum efficiency of the conversion process significantly, demonstrating the potential of DNA as structural element for ordering chromophores into functional π-systems, which may be employed in future organic solar cells

Thiol-yne crosslinked triarylamine hole transport layers for solution-processable organic light-emitting diodes

Triarylamine derivatives are widely used for hole transport in organic optoelectronic devices, but their excellent solubility in many common solvents limits their use for multi-layer device fabrication from solution. In this work, a novel process to the formation of conjugated triarylamine polymer thin-film networks by crosslinking of thiol-substituted and alkyne-substituted triarylamines is investigated. After deposition of the monomer blend and crosslinking under UV exposure, an insoluble thiol-yne polymer network is formed. The applicability of the thiol-yne polymer network as hole-transport layers is exemplified on organic light-emitting diodes. Its implementation reduces the device degradation as compared to OLEDs comprising hole-transport layers from PEDOT:PSS

White Dendrimer Organic Light Emitting Diodes: Exciton Formation and Transfer

In this work solution‐processed organic white‐light emitting diodes comprising a blend of red and blue phosphorescent dendrimers are presented. In contrast to common small molecule blended‐dye organic light emitting diodes (OLEDs), the bulky dendrons between the light emitting moieties increase the spacing and hamper the transfer of excitons between the dyes. The reduced transfer of the excitons from the blue dye to the red dye enables greater control over OLED color avoiding the issue in which small variations in the concentration of the red dye can dramatically change the emission color. Thus, the approach leads to enhanced manufacturing reproducibility. Transient electroluminescence measurements provide detailed insights into the charge carrier and exciton formation and transfer dynamics within the device

Acceptor Derivatization of the 4CzIPN TADF System : Color Tuning and Introduction of Functional Groups

We demonstrate modular modifications of the widely employed emitter 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) by replacing one or both nitrile acceptors with oxadiazole groups via a tetrazole intermediate. This allows the introduction of various functional groups including halides, alkynes, alkenes, nitriles, esters, ethers and a protected amino acid while preserving the thermally activated delayed fluorescence (TADF) properties. The substituents control the emission maximum of the corresponding emitters, ranging between 472-527 nm, and show high solid-state photoluminescence quantum yields up to 85 %. The TADF emission of two compounds, 4CzCNOXDtBu and 4CzdOXDtBu, a mono- and a bis-oxadiazole substituted 4CzIPN is characterized in detail by time- and temperature-dependent photoluminescence. Solution-processed OLEDs comprising 4CzCNOXDtBu and 4CzdOXDtBu show a significant blue-shift of the emission compared to the reference 4CzIPN, with external quantum efficiencies of 16 %, 5.9 % and 17 % at 100 cd m(-2), respectively.Peer reviewe

Acceptor Derivatization of the 4CzIPN TADF System: Color Tuning and Introduction of Functional Groups

We demonstrate modular modifications of the widely employed emitter 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) by replacing one or both nitrile acceptors with oxadiazole groups via a tetrazole intermediate. This allows the introduction of various functional groups including halides, alkynes, alkenes, nitriles, esters, ethers and a protected amino acid while preserving the thermally activated delayed fluorescence (TADF) properties. The substituents control the emission maximum of the corresponding emitters, ranging between 472–527 nm, and show high solid-state photoluminescence quantum yields up to 85%. The TADF emission of two compounds, 4CzCNOXDtBu and 4CzdOXDtBu, a mono- and a bis-oxadiazole substituted 4CzIPN is characterized in detail by time- and temperaturedependent photoluminescence. Solution-processed OLEDs comprising 4CzCNOXDtBu and 4CzdOXDtBu show a significant blue-shift of the emission compared to the reference 4CzIPN, with external quantum efficiencies of 16%, 5.9% and 17% at 100 cdm⁻², respectively

Childhood physical abuse and emotional neglect are specifically associated with adult mental disorders

Background: Childhood adversities and trauma (CAT) are associated with adult mental disorders. Nevertheless, although CAT of different domains mostly co-occurs, and co-morbidity is common, the associations between CAT and mental disorders, when taking these interrelations into account, are not well known.Aims: We aimed to study differential associations between the five core domains of CAT and current axis-I disorders, taking into consideration their interrelations.Methods: Four hundred and fifteen outpatients attending adult primary (n = 255) and psychiatric care (n = 160) were assessed with the Trauma and Distress Scale (TADS) and the Mini International Neuropsychiatric Interview (MINI). Associations between CAT core domains and diagnostic categories were examined by path analyses.Results: At least some infrequent experience of CAT (83.6%), mostly of neglect, and current mental disorders (49.4%), mostly depression, was frequent, as were co-morbidities and co-occurrence of CAT domains. Considering these interrelations in a path model of excellent fit, physical abuse predicted depressive, manic, psychotic and anxiety disorders, whereas emotional neglect predicted depressive, anxiety and substance misuse disorders.Conclusions: Of all five CAT core domains, physical abuse and emotional neglect had the strongest association with adult psychiatric disorders and might have transmitted earlier reported main effects of other CAT domains onto mental disorders.</p

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