2,7-Carbazolenevinylene-Based Oligomer Thin-Film Transistors: High Mobility Through Structural Ordering

Authors

  • N. Drolet,

    1. Département de Chimie, Centre de Recherche en Sciences et Ingénierie des Macromolécules, Université Laval, Quebec City, QC G1K 7P4, Canada
    2. Institute of Microstructural Sciences, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada
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  • J.-F. Morin,

    1. Département de Chimie, Centre de Recherche en Sciences et Ingénierie des Macromolécules, Université Laval, Quebec City, QC G1K 7P4, Canada
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  • N. Leclerc,

    1. Département de Chimie, Centre de Recherche en Sciences et Ingénierie des Macromolécules, Université Laval, Quebec City, QC G1K 7P4, Canada
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  • S. Wakim,

    1. Département de Chimie, Centre de Recherche en Sciences et Ingénierie des Macromolécules, Université Laval, Quebec City, QC G1K 7P4, Canada
    2. Institute of Microstructural Sciences, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada
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  • Y. Tao,

    1. Institute of Microstructural Sciences, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada
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  • M. Leclerc

    1. Département de Chimie, Centre de Recherche en Sciences et Ingénierie des Macromolécules, Université Laval, Quebec City, QC G1K 7P4, Canada
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  • This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada (NSERC) and Canada Research Chair Program. We thank Rodica Plesu, Jean Frenette, and Michel Beaulieu for assistance with some aspects of the experimental work.

Abstract

We have fabricated organic field-effect transistors based on thin films of 2,7-carbazole oligomeric semiconductors 1,4-bis(vinylene-(N-hexyl-2-carbazole))phenylene (CPC), 1,4-bis(vinylene-(N′-methyl-7′-hexyl-2′-carbazole))benzene (RCPCR), N-hexyl-2,7-bis(vinylene-(N-hexyl-2-carbazole))carbazole (CCC), and N-methyl-2,7-bis(vinylene-(7-hexyl-N-methyl-2-carbazole))carbazole (RCCCR). The organic semiconductors are deposited by thermal evaporation on bare and chemically modified silicon dioxide surfaces (SiO2/Si) held at different temperatures varying from 25 to 200 °C during deposition. The resulting thin films have been characterized using UV-vis and Fourier-transform infrared spectroscopies, scanning electron microscopy, and X-ray diffraction, and the observed top-contact transistor performances have been correlated with thin-film properties. We found that these new π-conjugated oligomers can form highly ordered structures and reach high hole mobilities. Devices using CPC as the active semiconductor have exhibited mobilities as high as 0.3 cm2 V–1 s–1 with on/off current ratios of up to 107. These features make CPC and 2,7-carbazolenevinylene-based oligomers attractive candidates for device applications.

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