Patterning And Processing Of Organic Electronic Devices Using Photolithography

Abstract

Patterning methods for chemically sensitive organic semiconductors are developed and applied to making devices and studying interesting device physics. The patterning methods developed center around industry standard photolithographic techniques, to take advantage of their high resolution, good registration and ubiquity. First, in Chapter 2, parylene is used as a mechanically removable liftoff mask to pattern both polymers and small molecules. In Chapter 3 this technique is applied to organic thin-film transistors to pattern both the conducting polymer electrodes and the organic active region. Chapter 4 applies the same technique to examine in detail the ionic transport of ionic transition metal complexes, which are candidates for very simple and stable solid-state lighting devices. By patterning the material, planar devices are made to resemble sandwich structure devices and a scanning probe technique can be used to see the electric field distribution of the device over time. Chapters 5 and 6 explore the use of fluorinated solvents to make organic compatible photoresist systems capable of directly patterning organic materials. First, the solvents and resists themselves are introduced in Chapter 5 and then both individual organic transistors of high performance and organic circuits are demonstrated using these resists to structure the active layers and contacts.