Daewoo Suh

Flexible, transparent single-walled carbon nanotube transistors with graphene electrodes.

This paper reports a mechanically flexible, transparent thin film transistor that uses graphene as a conducting electrode and single-walled carbon nanotubes (SWNTs) as a semiconducting channel. These SWNTs and graphene films were printed on flexible plastic substrates using a printing method. The resulting devices exhibited a mobility of ∼ 2 cm(2) V(-1) s -1), On/Off ratio of ∼ 10(2), transmittance of ∼ 81% and excellent mechanical bendability.

Silver-plated carbon nanotubes for silver/conducting polymer composites

Carbon nanotubes (CNTs) have advantages as conductive fillers due to their large aspect ratio and excellent conductivity. In this study, a novel silver/conducting polymer composite was developed by the incorporation of silver-plated CNTs. It is important to achieve a homogeneous dispersion of nanotubes and to improve the interfacial bonding to utilize the excellent properties of reinforcements in the matrix material. The homogeneous dispersion of nanotubes was achieved by an acid treatment process, and the interfacial contact was improved by electroless silver plating around nanotubes. The resistivity of the silver/conducting polymer composite was decreased by 83% by the addition of silver-plated single-walled carbon nanotubes. Conductive bumps were also screen-printed to demonstrate the capability of the composite as electrical interconnects for multi-layer printed circuit boards.

Ultrahigh Thermal Conductivity of Interface Materials by Silver-Functionalized Carbon Nanotube Phonon Conduits

An ultrahigh thermal conductivity (κ = 160 W m(-1) K(-1) ) of thermal interface materials is achieved with a high enhancement factor (96). A small amount (2.3 vol%) of 1D multiwalled carbon nanotubes (MWNTs) with high κ constructs effective phonon transport pathways between microscale silver-flake islands, and a solid phonon transport junction is realized by the coalescence of silver nanoparticles pre-functionalized on the MWNTs.

Enhanced thermoelectric properties of tungsten disulfide-multiwalled carbon nanotube composites

We investigated WS2–multiwalled carbon nanotube composites prepared by powder metallurgy. The inclusion of a small amount of nanotubes (0.75 wt%) dramatically increased electrical conductivity (by 12 300%) with a moderate decrease in the Seebeck coefficient (by 22%) and thermal conductivity (by 43%) enhancing both power factor and thermoelectric figure of merit at 300 K.

A drastic reduction in silver concentration of metallic ink by the use of single-walled carbon nanotubes decorated with silver nanoparticles

The concentration of Ag nanoparticles in metallic inks was significantly decreased to 3 wt% by a small addition of single-walled carbon nanotubes decorated with Ag nanoparticles (0.003 wt%) while maintaining high conductivity. The stability was good, and conductive patterns were printed using an inkjet device.

Unusual strain-dependent thermal conductivity modulation of silver nanoflower-polyurethane fibers

Thermal management of stretchable and wearable electronic devices is an important issue in enhancing performance, reliability, and human thermal comfort. Here, we constructed a unique experimental setup which investigated the strain-dependent thermal conductivity. The thermal conductivity of flower-shaped silver nanoparticle (silver nanoflower)-polyurethane (Ag-PU) composite fibers was systematically investigated as a function of strain. The strain-dependent temperature distribution of the Joule-heated fiber was measured using an infrared camera, and the thermal conductivity was obtained from the 1-dimensional Fouriers conduction model. There was a monotonic decrease in both lattice and electronic thermal conductivity with stretching at 25 °C. However, there was an initial increase in lattice and total thermal conductivity in the low strain region (<10%), when the fiber was stretched at 45 °C, although the electronic thermal conductivity decreased monotonically. The softening of the polymer at increased temperatures enhanced Poissons ratio. Resultantly, the fiber cross-sectional area and radial-direction inter-particle distance between silver nanoflowers decreased. This could increase the thermal transport in conductive fibers by modulating the interfaces between silver nanoflowers and polyurethane. A further stretching decreased the lattice thermal conductivity due to the significantly increased axial distance between silver nanoflowers and the decreased filler fraction. The weft-knitted fabric also demonstrated an increased thermal conductance in the low strain region (≤30%) at 45 °C.

Carbon nanotubes decorated with silver nano particles for conductive pastes and transparent conductive films

In this paper multiwalled carbon nanotubes decorated with self-assembled nanosilver particles are prepared using AgNO3 and benzyl mercaptan. We further demonstrated the improvement in electrical conductivity of conductive pastes and transparent conductive films.