Epindolidiones—Versatile and Stable Hydrogen‐Bonded Pigments for Organic Field‐Effect Transistors and Light‐Emitting Diodes |
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| Authors: | Eric Daniel Głowacki Giuseppe Romanazzi Cigdem Yumusak Halime Coskun Uwe Monkowius Gundula Voss Max Burian Rainer T. Lechner Nicola Demitri Günther J. Redhammer Nevsal Sünger Gian Paolo Suranna Serdar Sariciftci |
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| Affiliation: | 1. Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University, Linz, Austria;2. Dipartimento di Ingegneria Civile Ambientale, del Territorio Edile e di Chimica (DICATECh), Politecnico di Bari, Via Orabona 4, Bari, Italy;3. Department of Physics, Faculty of Arts and Sciences, Yildiz Technical University, Davutpasa Campus, Esenler, Istanbul, Turkey;4. Institute of Inorganic Chemistry, Johannes Kepler University, Linz, Austria;5. Institute of Physics, Montanuniversitaet Leoben, Franz‐Josef‐Strasse, 18,, Leoben, Austria;6. Elettra – Sincrotrone Trieste, S. S. 14 Km 163.5 in Area Science Park, Basovizza, Trieste, Italy;7. Materialwissenschaften und Physik, Abteilung für Mineralogie, Paris‐Lodron Universit?t Salzburg, Salzburg, Austria;8. Solar Energy Institute, Ege University, Izmir, Turkey |
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| Abstract: | Hydrogen‐bonded pigments are remarkably stable high‐crystal lattice energy organic solids. Here a lesser‐known family of compounds, the epindolidiones, which demonstrates electronic transport with extraordinary stability, even in highly demanding aqueous environments, is reported. Hole mobilities in the range 0.05–1 cm2 V–1 s–1 can be achieved, with lower electron mobilities of up to 0.1 cm2 V–1 s–1. To help understand charge transport in epindolidiones, X‐ray diffraction is used to solve the crystal structure of 2,8‐difluoroepindolidione and 2,8‐dichloroepindolidione. Both derivatives crystallize with a linear‐chain H‐bonding lattice featuring two‐dimensional π–π stacking. Powder diffraction indicates that the unsubstituted epindolidione has very similar crystallinity. All types of epindolidiones measured here display strong low‐energy optical emission originating from excimeric states, which coexists with higher‐energy fluorescence. This can be exploited in light‐emitting diodes, which show the same hybrid singlet and low‐energy excimer electroluminescence. Low‐voltage FETs are fabricated with epindolidione, which operate reliably under repeated cyclic tests in different ionic solutions within the pH range 3–10 without degradation. Finally, in order to overcome the insolubility of epindolidiones in organic solvents, a chemical procedure is devised to allow solution‐processing via the introduction of suitable thermolabile solubilizing groups. This work shows the versatile potential of epindolidione pigments for electronics applications. |
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| Keywords: | hydrogen‐bonds organic semiconductors indigoids organic electronics organic field‐effect transistors organic pigments |
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