Crystallization-Arrested Viscoelastic Phase Separation in Semiconducting Polymer Gels
| Autor: | Dilhan M. Kalyon, Xiaoqing Kong, Jing He, Michael Delaney, Stephanie S. Lee, Yuhao Wang |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Polymers and Plastics Organic solar cell Process Chemistry and Technology Crystallization of polymers Organic Chemistry FOS: Physical sciences Applied Physics (physics.app-ph) Physics - Applied Physics Condensed Matter - Soft Condensed Matter Semiconducting polymer Viscoelasticity Characterization (materials science) law.invention Chemical engineering Rheology law Soft Condensed Matter (cond-mat.soft) Crystallization |
| Popis: | Through a combination of rheological characterization and temperature-variable imaging methods, a novel gelation pathway in dilute solutions of a semiconducting polymer to achieve interconnected, crystalline networks with hierarchical porosity is reported. Upon rapid cooling, solutions of regioregular poly(3-hexylthiophene) (RR-P3HT) in ortho-dichlorobenzene formed thermoreversible gels. Temperature-variable confocal microscopy revealed cooling-induced structural rearrangement to progress through viscoelastic phase separation. The phase separation process arrested prematurely during the formation of micron-sized solvent-rich "holes" within the RR-P3HT matrix due to intrachain crystallization. Cryogen-based scanning electron microscopy of RR P3HT gels revealed the existence of an interfibrillar network exhibiting nano-sized pores. Remarkably, these networks formed to equal gel strengths when a third component, either small molecule phenyl C61 butyric acid methyl ester (PCBM) or non-crystallizing regiorandom (Rra)-P3HT, was added to the solution. Organic solar cells in which the active layers were deposited from phase-separated solutions displayed 45% higher efficiency compared to reference cells. 34 pages, 5 figures and 8 supplemental figures |
| Databáze: | OpenAIRE |
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