Probing Electronic Properties of dendritic Ruthenium Complex bound to Single Walled Carbon Nanotubes
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0938-N07-09
Probing Electronic Properties of dendritic Ruthenium Complex bound to Single Walled Carbon Nanotubes Harsh Chaturvedi1, and Jordan Poler2 1 Physics and Optical Sciences, UNC Charlotte, 9201 University City Blvd., Charlotte, NC, 28223 2 Chemistry, UNC Charlotte, 9201 University City Blvd., Charlotte, NC, 28223 ABSTRACT We have functionalized single walled carbon nanotubes (SWNTs) using ruthenium centered organometallic supramolecular dendritic complexes. These dendrimers have multiple binding sites with chemically specified chirality. Most importantly, they are mechanically rigid. We have fabricated field effect transistors (FET) using these functionalized SWNTs. Devices were processed with standard optical lithography and high resolution e-beam lithography. We are using FET response of these devices to study charge injection into the nanotubes and the resultant effect on the tube’s transport properties. Organometallic based molecular adsorbents onto the nanotubes effect the transistor response. These functionalized tubes change their majority carriers from holes to electrons in these FETs. We believe this is due to charge transfer from the metal center through the ligand and finally onto the nanotube. This results in the potential for optically altering the carrier density, and therefore the transport properties of the nanotubes.
INTRODUCTION Since their discovery 1, single walled carbon nanotubes have been regarded as important materials for future molecular devices. The exceptional mechanical, electronic and Optoelectronic characteristics 2 of SWNTs make them important materials for future nanodevices. SWNTs have been fabricated into field effect transistors 3-4. The field effect transistor response 5 of the SWNT devices has been fairly well documented. Functionalization of SWNTs using various polymers 6, nucleic acid 7 have been shown. We have functionalized SWNTs using ruthenium dendrimers. These dendrimers have multiple binding sites with chemically specified chirality. They are mechanically rigid, planar and are excellent optical absorbers. This enables the multidimensional constraints, geometry, required for advanced electronic, and optoelectronic devices. We have used the field effect transistor to probe the electronic properties of these functionalized SWNTs. FET response of these functionalized SWNTs have shown distinct characteristic variance as compare to pristine SWNTs. The variance is consistent with our proposed model.
EXPERIMENTAL SECTION Comparing characteristics of pristine SWNTs to functionalized SWNTs will help us study the charge transport phenomenon in the tubes bound with these supramolecular dendritic structures. All SWNT used were as purchased (Carbon Nanotechnologies Inc. Grade P). Dispersions of CNT (~1 mg/L) were made in N-N Dimethylforamide (DMF). Solutions were ultrasonicated for 30 min at 10-Watts (RMS) power. The opaque black solution was then filtered through glass wool to obtain a well-dispersed clear grey solution. The solution remained well dispersed for weeks to m
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