Abstract
Ultrathin films of regioregular poly(3-hexyl thiophene) (RR-P3HT) were deposited through a dip-coating technique and utilized as the semiconducting film in field-effect transistors (FETs). Proper selection of the substrate and solution concentration enabled the growth of a monolayer-thick RR-P3HT film. Atomic force microscopy (AFM), U-V-vis absorption spectroscopy, X-ray reflectivity, and grazing incidence diffraction were used to study the growth mechanism, thickness and orientation of self-organized monolayer thick RR-P3HT films on SiO2 surfaces. Films were found to adopt a Stranski-Krastanov-type growth mode with formation of a very stable first monolayer. X-ray measurements show that the direction of pi-stacking in the films (the (010) direction) is parallel to the substrate, which is the preferred orientation for high field-effect carrier mobilities. The field-effect mobilities in all ultrathin films prepared in this study are lower than those obtained for thicker films spun on similar substrates. However, monolayer FETs provide a direct experimental system to study the charge transport at the charge accumulation layer.
Original language | English |
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Pages (from-to) | 10176-10182 |
Journal | Langmuir |
Volume | 18 |
Issue number | 26 |
DOIs | |
Publication status | Published - 1 Dec 2002 |
MoE publication type | A1 Journal article-refereed |
Keywords
- CHARGE,CIRCUITS,CONJUGATED POLYMERS,CRYSTALS,HIGH,HIGH-MOBILITY,LANGMUIR-BLODGETT-FILMS,OLIGOTHIOPHENES,RESOLUTION