Benzothiadiazole-based conjugated polyelectrolytes for interfacial engineering in optoelectronic devices
| Autor: | Francesco Carulli, Umberto Giovanella, Elisa Lassi, Francesco Galeotti, Silvia Luzzati, Mariacecilia Pasini, Benedetta M. Squeo |
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| Přispěvatelé: | Squeo, B, Carulli, F, Lassi, E, Galeotti, F, Giovanella, U, Luzzati, S, Pasini, M |
| Rok vydání: | 2019 |
| Předmět: |
conjugated polymer
business.industry Chemistry General Chemical Engineering 02 engineering and technology General Chemistry POC-17 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Conjugated Polyelectrolytes Polyelectrolyte interfacial engineering 0104 chemical sciences polyelectrolytes Optoelectronics 0210 nano-technology business optoelectronic Interfacial engineering polyelectrolyte |
| Zdroj: | Pure and Applied Chemistry. 91:477-488 |
| ISSN: | 1365-3075 0033-4545 |
| Popis: | Polar semiconducting polymers based on a conjugated polymer backbone endowed with chemically anchored polar groups on the side chains have proved to be particularly interesting as optimization layer at organic/cathode interface in optoelectronic devices. In particular, the pendant phosphonate groups impart water-alcohol solubility allowing easy solution processing, and improve electron injection thanks to both a favorable interfacial dipole of phosphonate groups and an intense coordination interaction between the phosphonate groups and Al cathode. In this work we synthesize alternating fluorene-benzothiadiazole copolymers by proposing a post-polymerization reaction to insert the phosphonate groups. Thanks to this approach it is possible to use standard Suzuki coupling conditions, simplifying the process of synthesis, purification and characterization. The polymer Poly[9,9-bis(6′-diethoxylphosphorylhexyl)-alt-benzothiadiazole] (P2), is tested in conventional organic solar cells as cathode interfacial layers showing, with respect to the control device, an increasing of all the photovoltaic parameters, with a final power conversion efficiency that reaches 5.35% starting from 4.6%. The same trend is observed for multilayered polymer light-emitting diodes with an external quantum efficiency of the P2-based PLED enhanced of 1.5 times with respect to the basic devices with bare Al cathode, and negligible roll-off efficiency. The synergic effects of energy gap modulation and of polar phosphonated pendant functionalities of P2 are compared with the corresponding fluorene-based polar homopolymer. Our results show that, not only a proper selection of side functionalities, but also the tailoring of the energy gap of cathode interfacial materials (CIMs) is a possible effective strategy to engineer cathode of different optoelectronic devices and enhance their performance. |
| Databáze: | OpenAIRE |
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