CARBON NANO-TUBE A4E-PAPER

Carbon nanotubes (CNTs) are tubular cylinders of carbon atoms that have electrical, mechanical, optical, thermal, and chemical characteristics. Distinct carbon nanotubes can conduct electricity better than copper, boasts higher tensile strength than steel, and absorbs heat better than diamond. In electronic applications, carbon nanotubes can have greater mobility compared to a single crystal silicon. To add to this, CNT is over 10,000 times thinner than a human hair.

Carbon nanotube-based color active matrix
electrophoretic display (EPD) e-paper at
the International Meeting on Information
Display (iMiD) at KINTEX,
Ilsan, Korea. (Credit: Unidym

There are multiple forms of carbon nanotubes varying in diameter, length, and in the tendency of the nanotubes to form ropes and bundles of tubes. Some forms of carbon nanotubes are metallic and highly conducting, whereas other forms are semiconducting, and can form the basis of electronic switches. One of the more remarkable attributes of CNT is that it is electrically conductive, but nearly totally translucent. The film is approximately 50 nanometers thick, and incredibly porous.

Carbon nanotube diameters range from about 0.5 to about 10 nanometers and their lengths are typically between a few nanometers and tens of microns. (Credit: Unidym)

Unidym’s president and CEO, Mr. Arthur L. Swift recently said: “Our ongoing successful collaboration with Samsung Electronics has delivered yet another world’s first achievement this year.” Samsung has previously demonstrated a 2.3 inch black and white active matrix EPD made with carbon nanotubes. This latest innovation is an achievement for the two companies as they have incorporated carbon nanotube transparent electrodes into current display technologies, with color and at a larger A4 size.

The major requirements needed to complete the new display were that the conductivity of the film must be analogous to current ITO technology (transparent semiconducting material used as an electrode on flat-panel displays), there must be evenness over large areas in films, and compatibility with different display technologies and fabrication processes must be present.

The company also mentions that the EPD has important advantages over conventional flat panel displays. EPDs have very low power consumption and bright light readability, which means that even under bright lights or sunlight, the user would be able to view the display clearly. Furthermore, since the device uses the thin CNT films, applications can include e-paper and displays with thin, flexible substrates. Power consumption is lowered due to the EPD’s ability to reflect light and therefore able to preserve text or images on the display without frequently refreshing.