Stable organic field-effect-transistors with high mobilities unaffected by supporting dielectric based on phenylene-bridged thienobenzothiophene
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich (Switzerland)
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, 1060 Vienna (Austria)
We report on the electrical properties of organic field-effect transistors (OFET) based on a new class of organic semiconductors. The molecules consist of the same thieno[2,3-b][1]benzothiophene building blocks, connected by different π-bridge spacers (ethylene, phenylene, and fluorophenylene). Molecular orbitals and highest occupied molecular orbital/lowest unoccupied molecular orbital energies were calculated and compared with results from cyclic voltammetric and UV-vis absorption measurements. In order to study the influence of the bridge groups on the molecular arrangement and surface interaction, the transistor performance on a wide range of dielectrics has been investigated in detail. These include as grown SiO{sub 2} and Al{sub 2}O{sub 3} and also treated with octadecyltrichrolosilane and octadecylphosphonic acid, as well as Cytop and Parylene C. An extended study of the multitude of combinations of these materials revealed mobilities up to ∼1 cm{sup 2}/Vs, measured for devices made of the phenylene-bridged compound. Surprisingly, the mobility was quite independent of the supporting gate dielectric. Stability over time has been observed with no degradation after 5 months. By eliminating the hysteresis using Cytop, we were able to show that some of the molecules form films without long-term charge carrier trapping. These are interesting features for practical industrial processing of organic electronics.
- OSTI ID:
- 22275651
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM OXIDES
CARRIER MOBILITY
CHARGE CARRIERS
COMPARATIVE EVALUATIONS
DIELECTRIC MATERIALS
ELECTRICAL PROPERTIES
ETHYLENE
FIELD EFFECT TRANSISTORS
MOLECULAR ORBITAL METHOD
MOLECULES
ORGANIC SEMICONDUCTORS
SILICON OXIDES
THIONAPHTHENES
VOLTAMETRY