Suddhasattwa Nad | PubMed Health

PubMed2006

Probing electrostatic potentials in solution with carbon nanotube transistors.

We have used single-walled carbon nanotube transistors to measure changes in the chemical potential of a solution due to redox-active transition-metal complexes. The interaction of the molecules with a gold electrolyte-gate wire changes the electrostatic potential sensed by the nanotube, which in turn shifts the gate-voltage dependence of the nanotube conductance. As predicted by the Nernst equation, this shift depends logarithmically on the ratio of oxidized to reduced molecules.

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PubMed2003

Anomalous nanostructured titanium dioxide.

Titanium dioxide nanoparticles prepared in water-in-oil microemulsion droplets by controlled hydrolysis of TiCl(4)-generated crystalline nanoparticles of sizes from 115 nm down to 6 nm diameter depending on the size of the aqueous core of the micellar droplets. Powder X-ray diffraction of the vacuum-dried product (without sintering) indicated the presence of an unusual type of orthorhombic crystal structure nearly similar to titanium dioxide crystals prepared at high pressure. On gradual heating up to 900 degrees C these metastable crystals are converted into relatively more stable nanorods perhaps through making and breaking of the Ti-O-Ti bonds. It has been concluded that chemical pressure generated within the constrained volume of aqueous core of the reverse micellar droplets is responsible for the unusual crystal structure of TiO(2) nanoparticles.

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