Vertical confinement and interface effects on the microstructure and charge transport of P3HT thin films
| Autor: | Leslie H. Jimison, Scott Himmelberger, Jonathan Rivnay, Michael F. Toney, Alberto Salleo, Duc T. Duong |
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| Rok vydání: | 2013 |
| Předmět: |
Electron mobility
Materials science Polymers and Plastics business.industry Nanotechnology Substrate (electronics) Condensed Matter Physics Organic semiconductor Semiconductor Thin-film transistor Monolayer Materials Chemistry Optoelectronics Charge carrier Physical and Theoretical Chemistry Thin film business |
| Zdroj: | Journal of Polymer Science Part B: Polymer Physics. 51:611-620 |
| ISSN: | 0887-6266 |
| Popis: | Using X-ray diffraction-based pole figures, we pres-ent quantitative analysis of the microstructure of poly(3-hex-ylthiophene) thin films of varying thicknesses, which allows usto determine the crystallinity and microstructure at the semi-conductor-dielectric interface. We find that the interface isapproximately one fourth as crystalline as the bulk of the mate-rial. Furthermore, the use of a self-assembled monolayer(SAM) enhances the density of interface-nucleated crystallitesby a factor of 20. Charge transport measurements as a func-tion of film thickness correlate with interface crystallinity.Hence, we establish the crucial role of SAMs as nucleatingagents for increasing carrier mobility in field-effect devices. V C 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys000: 000–000, 2013 KEYWORDS: charge transport; crystallization; structure-propertyrelations; thin films; X-rayINTRODUCTION Organic semiconductors, comprising smallmolecules and conjugated polymers, are a promising materi-als family for next generation electronic devices such as tran-sistors, light-emitting diodes and solar cells. Processes atinterfaces play a very important role in the operation ofthese devices. Because in organic semiconductors the micro-structure is intimately tied to their electronic properties,understanding the effect of surfaces and interfaces on themorphology of these materials is an important component ofoptimizing their performance. In thin film transistors (TFTs)for instance, mobile charge is transported within a few nano-meters of the semiconductor/dielectric interface, which inthe case of bottom-gated devices is the substrate surface.There is significant experimental evidence demonstratingthat controlling the molecular packing and orientation at thedielectric interface can improve the charge carrier mobilityin thin films of poly(3-hexylthiophene) (P3HT), a modelsemicrystalline, semiconducting polymer, by several ordersof magnitude. |
| Databáze: | OpenAIRE |
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