King Abdullah University of Science & Technology: Composite Collaboration Leads to Faster Plastic Electronics

JEDDAH, Saudi Arabia, April 30, 2012 - The speed with which your smart
phone reacts to your touch as you swipe it is governed by the rate at
which electrical charges move through the various display components.
Scientists from Imperial College London (ICL) have collaborated with
colleagues at King Abdullah University of Science and Technology
(KAUST) to produce organic thin-film transistors (OTFTs) that
consistently achieve record-breaking carrier mobility through careful
solution-processing of a blend of two organic semiconductors. The
OTFTs and their processing methods offer a host of future electronic
applications.

Professor Aram Amassian's group at KAUST teamed with Dr. Thomas
Anthopoulos, Department of Physics, ICL, and colleagues Professor Iain
McCulloch and Dr. Martin Heeney, Department of Chemistry, to develop
and characterize a composite material that enhances the charge
transport and enables the fabrication of faster organic transistors.
They described their novel semiconductor blend in a joint paper
published in Advanced Materials,
http://onlinelibrary.wiley.com/doi/10.1002/adma.201200088/abstract

In this collective work, chemists from Imperial, working with device
physicists in the College's Centre for Plastic Electronics
(http://www3.imperial.ac.uk/plasticelectronics) and material
scientists at KAUST combined the advantageous properties of both
polymer and small molecules in one composite material, which offers
higher performance than do these components alone, while enhancing
device-to-device reproducibility and stability.

The improved performance is attributed in part to the crystalline
texture of the small-molecule component of the blend and to the
flatness and smoothness achieved at the top surface of the
polycrystalline film. The latter is crucial in top-gate,
bottom-contact configuration devices whereby the top surface of the
semiconductor blend forms the semiconductor-dielectric interface when
solution-coated by the polymer dielectric.

The materials scientists at KAUST addressed the phase separation,
crystallinity, and morphology of the organic semiconductor blend by
using a combination of synchrotron-based X-ray scattering at the D1
beam line of the Cornell High Energy Synchrotron Source (CHESS),
cross-sectional energy-filtered transmission electron microscopy
(EF-TEM), and atomic force microscopy in topographic and phase modes.

"In principle, this simple blend approach could lead to the
development of organic transistors with performing characteristics
well beyond the current state-of-the-art," added Dr. Anthopoulos.