• Record-setting organic transistor heralds new gen of transparent electronics

    Transparent transistors on this postage-stamp sized glass have speed characteristics rivalling some forms of silicon transistors.
    Image credit: Jinsong Huang and Yongbo Yuan
    Date:10 January 2014 Tags:, ,

    Engineers have produced the world’s fastest thin-film organic transistors, which could become the foundation for cheap, high-performance displays.

    In the journal Nature Communications, engineers from the University of Nebraska-Lincoln (UNL) and Stanford University show how they created thin-film organic transistors that could operate more than five times faster than previous examples of this experimental technology.

    The research collaboration used their new process to make organic thin-film transistors with electronic characteristics comparable to those found in expensive, curved-screen television displays based on a form of silicon technology.

    They achieved their speed boost by altering the basic process for making thin film organic transistors.

    Typically, researchers drop a special solution, containing carbon-rich molecules and a complementary plastic, onto a spinning platter – in this case, one made of glass. The spinning action deposits a thin coating of the materials over the platter.

    In their Nature Communications paper, the collaborators describe two important changes to this basic process.

    First they spun the platter faster. Second they only coated a tiny portion of the spinning surface, equivalent to the size of a postage stamp.

    These innovations had the effect of depositing a denser concentration of the organic molecules into a more regular alignment. The result was a great improvement in carrier mobility, which measures how quickly electrical charges travel through the transistor.

    The researchers called this improved method “off-centre spin coating”. The process remains experimental, and the engineers cannot yet precisely control the alignment of organic materials in their transistors, or achieve uniform carrier mobility.

    Further improvements to this experimental process could lead to the development of inexpensive, high-performance electronics built on transparent substrates such as glass and, eventually, clear and flexible plastics.

    Source: Stanford University