Nano-Confinement Induced Chain Alignment in Ordered P3HT Nanostructures Defined by Nanoimprint Lithography
- 4 September 2009
- journal article
- Published by American Chemical Society (ACS) in ACS Nano
- Vol. 3 (10), 3085-3090
- https://doi.org/10.1021/nn900831m
Abstract
Control of polymer morphology and chain orientation is of great importance in organic solar cells and field effect transistors (OFETs). Here we report the use of nanoimprint lithography to fabricate large-area, high-density, and ordered nanostructures in conjugated polymer poly(3-hexylthiophene) or P3HT, and also to simultaneously control 3D chain alignment within these P3HT nanostructures. Out-of-plane and in-plane grazing incident X-ray diffraction were used to determine the chain orientation in the imprinted P3HT nanostructures, which shows a strong dependence on their geometry (gratings or pillars). Vertical chain alignment was observed in both nanogratings and nanopillars, indicating strong potential to improve charge transport and optical properties for solar cells in comparison to bulk heterojunction structure. For P3HT nanogratings, pi-pi stacking along the grating direction with an angular distribution of +/-20 degrees was found, which is favorable for OFETs. We propose the chain alignment is induced by the nanoconfinement during nanoimprinting via pi-pi interaction and hydrophobic interaction between polymer chain and mold surfaces.Keywords
This publication has 33 references indexed in Scilit:
- Introducing organic nanowire transistorsMaterials Today, 2008
- Organic Solar Cells: An Overview Focusing on Active Layer MorphologyPhotosynthesis Research, 2006
- Organic solar cells: An overviewJournal of Materials Research, 2004
- High-Performance Semiconducting Polythiophenes for Organic Thin-Film TransistorsJournal of the American Chemical Society, 2004
- The interplay of efficiency and morphology in photovoltaic devices based on interpenetrating networks of conjugated polymers with fullerenesSynthetic Metals, 2001
- Optical constants of highly stretch-oriented poly(p-phenylene-vinylene): A joint experimental and theoretical studyPhysical Review B, 2000
- Mobility enhancement in conjugated polymer field-effect transistors through chain alignment in a liquid-crystalline phaseApplied Physics Letters, 2000
- Two-dimensional charge transport in self-organized, high-mobility conjugated polymersNature, 1999
- Electroluminescence in conjugated polymersNature, 1999
- Optical anisotropy of neutral and doped poly(3-octylthiophene)Solid State Communications, 1990