Jae Hee Song

Dose rate and irradiation time effects on the shape of Au nanomaterials under proton beam irradiation

A synthetic route is presented for the high yield production of Au nanomaterials via a simple proton beam irradiation process. We were able to prepare Au nanomaterials under a proton beam at low concentration of cetyltrimethylammonium bromide at room temperature. It was observed that the size and shape of the prepared gold nanocrystals were easily controlled by the dose rate and irradiation time of the proton beam. When the dose rate of the proton beam was kept constant, a shape transition of Au crystals from particles to nanorods/nanowires and then again to particles was observed as the duration time was increased. When the total dose was kept constant by varying the dose rate and duration time of the proton beam, there was an apparent change in the feature size and shape of the Au nanomaterials produced under proton beam irradiation. Once the dose rate reached a proper value, very similar feature shapes of gold nanocrystals were produced, as long as the total dose was constant.

Tailored Secondary Growth on Au Nanorods through Regioselective Adsorption

Precise controlling nanostructures of nanosized metals using simple process will be very important for developing novel metal inks for printing electrodes and wires. In this paper, Au nanorods were used as seeds for the tailored secondary growth of thin shell of gold or silver by using a mild reducing agent, ascorbic acid, in the presence of cetyltrimethylammonium bromide under ambient conditions. We could tailor the secondary growth of sheathes of gold and silver on gold nanorods via regioselective adsorption on Au nanorods. Before we grew thin sheath of Au or Ag, 1,3-propanedithiol was introduced first to be regioselectively adsorbed on {111} and {100} planes of gold nanorod seeds to prevent the secondary crystal growth so that the sheath crystal could grow favorably to the direction of {110} planes of the seeds.

Preparation of Au Nanomaterials via Pulsed Proton Beam Irradiation

A new solution phase method is presented for the synthesis of gold nanomaterials by using a pulsed proton beam irradiation process at room...

Formulation of high conducting ink using composites of Ag nanoparticles, Ag nanowires, and polyaniline

In this presentation, we will demonstrate a new way of formulation method for electronic inks that have a comparable electrical conductivity (2.3 times 105 S/cm) to the copper films.

Organic memory device using tailored nanostructure of conducting polymer

In this presentation, a simple printing method to fabricate molecular memory cells will be presented using tailored nanostructure of poly(ethylenedioxythiophene) derivatives (PEDOTD). Synthetic approach to tune the nanostructure of PEDOTD and its electrical properties will be presented with the printing condition, NDR effect, and characteristics for molecular electronics.