Deep blue oxadiazole-containing thermally activated delayed fluorescence emitters for organic light-emitting diodes

EZ-C thanks the University of St Andrews for support. The authors are grateful to the EPSRC for financial support (grants EP/P010482/1, EP/J01771X and EP/J00916). IDWS is a Royal Society Wolfson Research Merit Award Holder. CM acknowledges funding by the European Commission through a Marie Skłodowska Curie Individual Fellowship (No. 703387).A series of four novel deep blue to sky blue thermally activated delayed fluorescence (TADF) emitters (2CzdOXDMe, 2CzdOXD4MeOPh, 2CzdOXDPh and 2CzdOXD4CF3Ph) have been synthesized and characterized. These oxadiazole-based emitters demonstrated bluer emission compared with reference emitter 2CzPN thanks to the weaker acceptor strength of oxadiazole moieties. In particular, the oxadiazole compounds doped in hosts (mCP and PPT) emitted from 435-474 nm with photoluminescence quantum yields ranging from 14%-55%. The emitters possess relatively large singlet-triplet excited state energy gaps (ΔEST) from 0.25-0.46 eV resulting in long lifetimes of the delayed components ranging from 4.8 to 25.8 ms. Electroluminescent devices using these oxadiazole emitters as dopant emitters gave emission maxima (λEL) from 446 nm to 474 nm with maximum external quantum efficiencies ranging from 4.2-11.2%.PostprintPeer reviewe

Odorless fatty esters : understanding of phenomena and innovative deodorization strategies

Les esters gras sont connus pour leur polyvalence et sont employés dans de nombreux domaines (cosmétique, agroalimentaire, pharmaceutique). Néanmoins, ils doivent répondre à de plus en plus de critères pour être employés dans les formulations de divers produits du quotidien. En plus de leur performance en tant qu’émollients, émulsifiants, solubilisants ou agents dispersants, ils doivent notamment présenter des caractéristiques olfactives les plus neutres possibles. Or, bien que les esters gras soient désodorisés au cours de leur synthèse, certains présentent encore une faible odeur résiduelle en fin de procédé. L’enjeu de ce projet est de caractériser les composés volatils responsables de l’odeur des esters gras, de manière à orienter, par la suite, le choix des stratégies de désodorisation à mettre en place pour réduire l’odeur résiduelle.Dans ce but, l’odeur de trois esters gras a été évaluée sensoriellement en considérant les critères d’intensité odorante et de profil olfactif. La composition de l’espace de tête de ces esters a également été déterminée avec microextraction sur phase solide (SPME) des composés volatils et analyses GC-MS. Enfin, les composés odorants qui participent à l’odeur résiduelle des esters gras ont été identifiés par analyse GC-MS-O. Le procédé industriel de désodorisation des esters a ensuite été étudié à la lumière de ces résultats afin d’être optimisé. Par ailleurs, l’impact de différents adsorbants sur les composés odorants des esters gras a été mis en avant.Fatty esters are well-known for their multi-functionality and they are used in many fields (cosmetics, agri-food, pharmaceutics). However, they have to meet more and more criteria to be employed in a variety of daily product formulations. In addition to their performance as emollients, emulsifiers, solubilizing or dispersing agents, they are expected to have the most neutral olfactive characteristics as possible. Although fatty esters are deodorized during their synthesis, some of them still have a slight residual odor at the end of the process. The main aim of this project is to characterize the volatile compounds responsible for the odor of fatty esters, in order to guide the choice of deodorization strategies to be implemented to reduce the residual odor.For this purpose, the odor of three fatty esters was evaluated sensorially considering the criteria of odor intensity and odor profile. The headspace composition of these esters was also determined with solid phase microextraction (SPME) of volatile compounds and GC-MS analyses. Finally, the odor-active compounds that contribute to the residual odor of the fatty esters were identified by GC-MS-O analyses. Besides, the industrial deodorization process of esters was then studied by taking these results into consideration in order to be optimized. Furthermore, the impact of different adsorbents on the odorous compounds of fatty esters was highlighted

Compréhension des odeurs résiduelles d'esters gars utilisés en cosmétique

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20-1: Invited paper: Towards deep-blue materials with efficient triplet harvesting

The development of materials for deep blue OLEDs will be presented. A novel donor‐acceptor TADF compound comprising oxadiazole acceptor units was studied. The emission is tuned towards deep‐blue by tuning the acceptor strength, and TADF is demonstrated. Finally, the results are compared with model sky‐blue emitter 2CzPN

Deep-Blue Oxadiazole-Containing Thermally Activated Delayed Fluorescence Emitters for Organic Light-Emitting Diodes

A series of four novel deep-blue to sky-blue thermally activated delayed fluorescence (TADF) emitters (2CzdOXDMe, 2CzdOXD4MeOPh, 2CzdOXDPh, and 2CzdOXD4CF3Ph) have been synthesized and characterized. These oxadiazole-based emitters demonstrated bluer emission compared with the reference emitter 2CzPN thanks to the weaker acceptor strength of the oxadiazole moieties. The oxadiazole compounds doped in hosts (mCP and PPT) emitted from 435 to 474 nm with photoluminescence quantum yields ranging from 14-55%. The emitters possess singlet-triplet excited-state energy gaps (\u394EST) between 0.25 and 0.46 eV resulting in delayed components ranging from 4.8 to 25.8 ms. The OLED device with 2CzdOXD4CF3Ph shows a maximum external quantum efficiency of 11.2% with a sky-blue emission at CIE of (0.17, 0.25), while the device with 2CzdOXD4MeOPh shows a maximum external quantum efficiency of 6.6% with a deep-blue emission at CIE of (0.15, 0.11)