The Chair of Display Technology at Universitaet Stuttgart has worked in collaboration with Nano Proprietary’s subsidiary, applied Nanotech Inc (ANI), to increase the fabrication yield of carbon nanotube (CNT) thin film transistors (TFTs) for use in displays, electronic circuits, sensors, memory chips and other applications that are transitioning from rigid substrates, such as silicon and glass, to flexible substrates.

ANI and the Universitaet Stuttgart have worked together to increase the fabrication yield of carbon nanotube TFTs using ANI’s proprietary printing-like method of carbon nanotube deposition. The TFTs exceed an on/off ratio of five orders of magnitude and achieve the electron mobility necessary for thei utilisation for low temperature plastic-based substrates.

At the last Society for Information Display (SID) International Symposium, held in May 2008, the Chair of Display Technology of Universitaet Stuttgart presented the world’s first full colour active matrix LCD where ITO as transparent conductive film (TCF) was completely replaced by random carbon nanotube (CNTs) networks. The display has a qVGA resolution (320xRGBx240) at 4” diagonal.

The CNT networks are deposited by spray coating from suspension, which replaces a costly vacuum process. This demonstrates for the first time the applicability of CNTs as TCF in a state-of-the-art amorphous silicon active matrix process. It also gives a great perspective for future flexible displays, since CNT networks are much more reliable in flexible applications than the amorphous ITO.

The complete display, including AM-backplane, color filters, and a dedicated addressing system was developed designed and fabricated at the Universitaet of Stuttgart.