Artykuły IChO PAN

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Displaying 1 - 5 of 113 records
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    Unprecedented roll-off ratio in high-performing red TADF OLED emitters featuring 2,3-Indole-annulated naphthalene imide and auxiliary donors
    (Royal Society of Chemistry, 2024) Grzelak, Magdalena; Kumar, Dharmendra; Kochman, Michał Andrzej; Morawiak, Maja; Wiosna-Sałyga, Gabriela; Kubas, Adam; Data, Przemysław; Lindner, Marcin; Institute of Organic Chemistry, Polish Academy of Sciences; Faculty of Chemistry, Łódź University of Technology; Institute of Physical Chemistry, Polish Academy of Sciences; Centre for Advanced Technologies, Adam Mickiewicz University
    The capability of organic emitters to harvest triplet excitons via a thermally activated delayed fluorescence (TADF) process has opened a new era in organic optoelectronics. Nevertheless, low brightness, and consequently insufficient roll-off ratio, constitutes a bottleneck for their practical applications in the domain of organic light-emitting diodes (OLEDs). To address this formidable challenge, we developed a new design of desymmetrized naphthalimide (NMI) featuring an annulated indole with a set of auxiliary donors on its periphery. Their perpendicular arrangement led to minimized HOMO-LUMO overlap, resulting in a low energy gap (ΔEST – 0.05-0.015 eV) and efficient TADF emission with a photoluminescence quantum yield (PLQY) ranging from 82.8% to 95.3%. Notably, the entire set of dyes (NMI-Ind-TBCBz, NMI-Ind-DMAc, NMI-Ind-PXZ, and NMI-Ind-PTZ) was utilized to fabricate TADF OLED devices, exhibiting yellow to red electroluminescence. Among them, red-emissive NMI-Ind-PTZ, containing phenothiazine as an electron-rich component, revealed predominant performance with a maximum external quantum efficiency (EQE) of 23.6%, accompanied by persistent luminance of 38,000 cd/m². This results in a unique roll-off ratio (EQE10 000 = 21.6%), delineating a straightforward path for their commercial use in lighting and display technologies
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    Quadrupolar, Highly Polarized Dyes: Emission Dependence on Viscosity and Selective Mitochondria Staining
    (American Chemical Society, 2024) Tasior, Mariusz; Vakuliuk, Olena; Wrzosek, Antoni; Vullev, Valentine I.; Szewczyk, Adam; Jacquemin, Denis; Gryko, Daniel T.; Institute of Organic Chemistry, Polish Academy of Sciences; Nencki Institute of Experimental Biology of Polish Academy of Sciences; University of California, Riverside, United States; Nantes Université, CNRS, CEISAM, France; Institut Universitaire de France (IUF)
    Quadrupolar A-D-A-type 1,4-dihydropyrrolo[3,2-b]pyrroles (DHPPs) bearing pyridinium and quinolinium substituents emit in the 500–600 nm region. The enhancement of electronic communication between the electron-rich heterocyclic core and electron-deficient peripheral substituents turned out to be crucial for achieving emission enhancement in viscous media. DHPP bearing two 4-pyridinium substituents has optical brightness 34,000 in glycerol and only 700 in MeOH, as evidenced by measurements of the emission intensity and fluorescence lifetimes in a series of polar solvents. Such behavior makes it an excellent candidate for viscosity probes in fluorescence microscopy, as demonstrated by the fluorescence imaging of H9C2 cardiomyocytes.
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    Photochemical cyclopropanation in aqueous micellar media – experimental and theoretical studies
    (Royal Society of Chemistry, 2024) Milton, Joseph P.; Milanowski, Adam; Andersson, Martin; Gryko, Dorota; Institute of Organic Chemistry, Polish Academy of Sciences; Department of Chemistry, Warsaw University of Technology; Center for Integrative Petroleum Research, King Fahd University of Petroleum and Minerals, Kingdom of Saudi Arabia
    While in nature, reactions occur in water-based confined compartments, for a long time, water has been often regarded as an unsuitable medium for organic reactions. We have, however, found that photochemical cyclopropanation of styrenes with diazo compounds or their precursors can be performed in micellar systems. COSMO-RS studies revealed that the reactivity correlates with the predicted critical micelle concentration (CMC), with higher CMC values delivering higher yields.
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    Remote control of anion binding by CH-based receptors
    (Royal Society of Chemistry, 2024) Jurek, Paulina; Szymański, Marek P.; Szumna, Agnieszka; Institute of Organic Chemistry, Polish Academy of Sciences
    We show that the substitution of tetra(benzimidazole)resorcin-[4]arenes with electron withdrawing groups on the upper rim enhances anion binding at the opposite edge by more than three orders of magnitude. Moreover, selective anion binding at either the OH/NH or CH binding sites is emonstrated.
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    Singlet Fission in a New Series of Systematically Designed Through-space Coupled Tetracene Oligomers
    (Wiley, 2024) Majdecki, Maciej; Hsu, Chao-Hsien; Wang, Chih-Hsing; Shi, Emily Hsue-Chi; Zakrocka, Magdalena; Wei, Yu-Chen; Chen, Bo-Han; Lu, Chih-Hsuan; Yang, Shang-Da; Chou, Pi-Tai; Gaweł, Przemysław; Institute of Organic Chemistry, Polish Academy of Sciences; Department of Chemistry, National Taiwan University; Institute of Photonics Technologies, National Tsing Hua University, Taiwan
    Singlet fission (SF) holds great promise for current photovoltaic technologies, where tetracenes, with their relatively high triplet energies, play a major role for application in silicon-based solar cells. However, the SF efficiencies in tetracene dimers are low due to the unfavorable energetics of their singlet and triplet energy levels. In the solid state, tetracene exhibits high yields of triplet formation through SF, raising great interest about the underlying mechanisms. To address this discrepancy, we designed and prepared a novel molecular system based on a hexaphenylbenzene core decorated with 2 to 6 tetracene chromophores. The spatial arrangement of tetracene units, induced by steric hindrance in the central part, dictates through-space coupling, making it a relevant model for solid-state chromophore organization. We then revealed a remarkable increase in SF quantum yield with the number of tetracenes, reaching quantitative (196 %) triplet pair formation in hexamer. We observed a short-lived correlated triplet pair and limited magnetic effects, indicating ineffective triplet dissociation in these through-space coupled systems. These findings emphasize the crucial role of the number of chromophores involved and the interchromophore arrangement for the SF efficiency. The insights gained from this study will aid designing more efficient and technology-compatible SF systems for applications in photovoltaics.