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Title: Conductivity of Langmuir-Blodgett films of a disk-shaped liquid-crystalline molecule-DNA complex studied by current-sensing atomic force microscopy
Authors: Nayak, Alpana
Suresh, K.A.
Issue Date: 27-Aug-2008
Publisher: American Physical Society
Citation: Physical Review E, 2008, Vol.78, p021606
Abstract: We have studied the electrical conductivity in monolayer films of an ionic disk-shaped liquid-crystal molecule, pyridinium tethered with hexaalkoxytriphenylene (PyTp), and its complex with DNA by current-sensing atomic force microscopy (CS-AFM). The pure PyTp and PyTp-DNA complex monolayer films were first formed at the air-water interface and then transferred onto conducting substrates by the Langmuir-Blodgett (LB) technique to study the nanoscale electron transport through these films. The conductive tip of CS-AFM, the LB film, and the metal substrate form a nanoscopic metal-LB film-metal (M-LB-M) junction. We have measured the current-voltage (I-V) characteristics for the M-LB-M junction using CS-AFM and have analyzed the data quantitatively. We find that the I-V curves fit well to the Fowler-Nordheim (FN) model, suggesting electron tunneling to be a possible mechanism for electron transport in our system. Further, analysis of the I-V curves based on the FN model yields the barrier heights of PyTp-DNA complex and pure PyTp films. Electron transport studies of films of ionic disk-shaped liquid-crystal molecules and their complex with DNA are important from the point of view of their applications in organic electronics.
Description: Open Access. Also in Virtual Journal of Nanoscale Science & Technology (Vol.18, No.10, Sept 8, 2008) and Virtual Journal of Biological Physics Research (Vol.16, No.5, Sept 1, 2008)
ISSN: E-ISSN: 1550-2376
P-ISSN: 1539-3755
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Copyright: 2008 The American Physical Society
Appears in Collections:Research Papers (SCM)

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