(2016) 'Exciplex enhancement as a tool to increase OLED device e ciency.', Journal of physical chemistry C., 120 (4). pp. 2070-2078. Further information on publisher's website:https://doi.org/10.1021/acs.jpcc.5b11263 Publisher's copyright statement: This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Journal of physical chemistry C, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see https://doi.org/10.1021/acs.jpcc.5b11263Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. derivatives that could be used as emitters in OLED devices. We were able to improve the of efficiency DPP materials by forming exciplex enhanced OLED devices. These organic materials were also characterized by electrochemical and spectroscopic methods in order to elucidate each molecule's interaction and decreasing the photoluminescence efficiency.2

Complex multi-redox-active organic semiconductors have been made incorporating tetrathiafulvalene as a fused bridge between oligothiophene chains.

Electrochemical and spectroelectrochemical properties of a series of new penta-ring donor -acceptor compounds, comprising 1,3,4-oxadiazole, 1,3,4-thiadiazole and 1,2,4-triazole central ring, symmetrically connected to substituted bithiophenes, were investigated. Aromaticity and electrophilic -nucleophilic traits of the aza-heterocyclic units, fostering inductive and resonance effects that translate to conjugation enhancement and electron (de)localization, were found a major factor determining the key electron properties of ionization potential (IP) and electron affinity (EA) of these molecules. Replacing the alkyl thiophene substituent for an alkoxy one, afforded certain control over the two parameters as well. All studied compounds were found to undergo electrochemical polymerization giving p and n-dopable products, featuring good electrochemical reversibility of their oxidative doping process, as demonstrated by cyclic voltammetry and UV-Vis-NIR, EPR spectroelectrochemistry. While electropolymerisation of entities differing in the heterodiazole unit was found to conserve the EA value, the IP parameter of polymerisation products was found to decrease by 0.6 to 0.7 eV affording an asymmetric narrowing of the frontier energy levels gap. Aided by quantum chemical computations, the effects of structure tailoring of the investigated systems are rationalized, pointing to conscious ways of shaping the electronic properties of thiophene class polymers using synthetically convenient heterodiazole π-conjugated units.

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The ambipolar behavior of groups of N-substituted and core-functionalized triarylamine arylene bisimides were investigated by electrochemical and spectroelectrochemical (UV-vis and EPR spectroelectrochemistry) techniques.

Thermally activated delayed fluorescence has been found in a group of tricarbazolylamines that are purely electrondonating, non-charge-transfer (CT) molecules. We show that the reverse intersystem crossing step in these materials is mediated through upper triplet states. Reverse internal conversion is shown to be the thermally activated mechanism behind the triplet harvesting mechanism. The strongly mixed n−π*/π−π* character of the lowest energy optical transitions retains high oscillator strength and gives rise to high Φ PL . Organic light-emitting diode devices using these materials were fabricated to show very narrow (full width at half-maximum = 38−41 nm) electroluminescence spectra, clearly demonstrating the excitonic nature of the excited states. This new combination of physicochemical properties of a non-CT molecule yields thermally activated delayed fluorescence, but via a different, physical mechanism, reverse internal conversion delayed fluorescence.

A novel organic material (C1) with the structure D–π–A–π–D was synthesised and characterised OLEDs based on C1 were fabricated.