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Title: Stable organic field-effect-transistors with high mobilities unaffected by supporting dielectric based on phenylene-bridged thienobenzothiophene

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.
Authors:
;  [1] ; ; ;  [2] ; ; ; ;  [3]
  1. Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich (Switzerland)
  2. Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, 315201 Ningbo (China)
  3. Institute of Applied Synthetic Chemistry, Vienna University of Technology, 1060 Vienna (Austria)
Publication Date:
OSTI Identifier:
22275651
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, 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