Katalysator-Transfer Polykondensation als synthetischer Zugang zu neuen n-Typ Halbleiterpolymere und deren Anwendung in der organischen Elektronik
Zusammenfassung der Projektergebnisse
Polythiazoles as n-type analogues to Polythiophenes: In the course of this project, we were able to establish head-to-tail-regioregular polythiazoles (rr-PTzs) as less electron-rich analogues to polythiophenes. We have made a number of derivatives available, including the highly crystalline PTzTHX, and a series of polymers with conjugated side-chains (PvTzs). PTzTHX showed very promising charge-carrier mobility that could directly be linked to its crystallinity and self-organization in the bulk, while PvTzs exhibit promising OPV-properties, due to their lower frontier orbital levels. The main challenge in this above project – that remains largely unreflected in the above report – were the efforts invested in the preparation thiazole-monomers with sufficiently well solubilizing side-chains to furnish characterizable and processible polymers. However, once soluble PTz-derivatives were made available, we could show that rr-PTzs can be prepared by chain-growth polycondensation, and that block-copolymers can thereby be accessed. The block-copolymer synthesis is of particular significance, since very few examples exist of all-conjugated block-copolymers that feature an electron poor second block. Ladder Boranes prepared by Hydroboration: Our work on the preparation of N→B-ladder boranes has shown that hydroboration of suitable substrates provides a reliable access to these compounds, and allows to readily vary the substituents on the boryl-group. We could also show that this, in turn, allows to incrementally vary the electron affinity of a given π-system over a broad range. Structurally diverse N→B-ladder boranes with electron affinities in the range of -3.4 to -4.4 eV can be readily prepared by this approach, which gives access to a whole class of compounds that are of interest as n-type materials in organic electronic applications, and may be tested in different devices in the future. This project has directly benefitted from the expertise gained from the synthesis of rr-PTzs, as it enabled us to prepare defect free regioregular 1-alkenyl-functionalized poly(pyridine)s. These were essential substrates for the subsequent post-functionalization to generate N→B-ladder polymers. The latter is one of the most significant achievements of this work, since it proves that the simultaneous introduction of multiple boryl-groups by hydroboration is not only possible, but can also serve to generate n-type polymers with highly variable electron affinities in the desirable range.
Projektbezogene Publikationen (Auswahl)
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„Soluble Head-to-Tail Regioregular Polythiazoles: Preparation, Properties and Evidence for Chain-Growth Behavior in the Synthesis via Kumada- Coupling Polycondensation", Macromolecules 2014, 47, 5904-5912
F. Pammer, J. Jäger, B. Rudolf, Y. Sun
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„Preparation of Head-to-Tail Regioregular 6-(1-Alkenyl)-Functionalized Poly(pyridine-2,5-diyl) and its Post-functionalization via Hydroboration”, Macromol. Chem. Phys. 2015, 216, 2249-2262
M. Grandl, F. Pammer
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„Generation of an N→B-Ladder-type Structure via Regioselective Hydroboration of an Alkenyl-Functionalized Quaterpyridine”, Chem. Eur. J. 2016, 22, 3976–3980
M. Grandl, Y. Sun, F. Pammer
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„Hydroboration as an Efficient Tool for the Preparation of Electronically and Structurally Diverse N→B-Heterocycles”, Chem. Eur. J. 2016, 22, 14373–14382
M. Grandl, T. Kaese, A. Krautsieder, Y. Sun, F. Pammer
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„Towards n-Type Analogues to Poly(3-alkylthiophene)s: Influence of Side-chain Variation on Bulk-morphology and Electron Transport Characteristics of Head-to-tail Regioregular Poly(4-alkylthiazole)s”, J. Mater Chem. C 2016, 4, 2587-2597
J. Jäger, N. Tchamba Yimga, M. Urdanpilleta, E. von Hauff, F. Pammer
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„Intramolecular N→B- Coordination as a Stabilizing a Scaffold for π-Conjugated Radical Anions with Tunable Redox Potential”, Organometallics 2017, 36, 2527–2535
M. Grandl, B. Rudolf, Y. Sun, D. F. Bechtel, A. J. Pierik, F. Pammer
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„Electronic and Structural Properties of N→B-Ladder Boranes With High Electron Affinity”, Org. Chem. Front. 2018, 5, 336-352
M. Grandl, Y. Sun, F. Pammer
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„Synthesis, Properties and Solar Cell Performance of Poly(4-(p-alkoxystyryl)thiazole)s", Macromol. Chem. Phys. 2018
J. Jäger, S. Schraff, F. Pammer
