Chemically Modified Ink-Jet Printed Electrodes for Organic Field-Effect Transistors
Conferences and Talks

• Gregory Whiting
• Tse Nga Ng
• Ana Arias

2010 Materials Research Society Fall Meeting

1 December 2010
8:30 a.m.
Boston, Massachusetts

description

Ink-jet printing is a desirable manufacturing technique for electronic devices as this mask-less, additive method should allow for integration of different electronic components over large substrate areas at low cost.  In order to realize entirely jet-printed devices, appropriate printed electrodes for organic semiconductor-based field effect transistors (FETs) must be chosen.  Generally, gold is used as the source and drain contacts for organic field-effect transistors.  While gold creates good contact with many organic semiconductors, its high price makes it non-ideal for large-scale manufacture.  There is therefore a desire to investigate other conductors for printed

devices, and typically printable conductive inks are silver based, which is lower cost and allows for low-temperature processing, but can lead to poor energy level matching with the organic semiconductor.  This report will study the use of both a nanoparticle silver ink as well as a soluble silver precursor ink and will show that by modifying the surface chemistry of the printed silver contacts through solution-based self-assembly of the organic electron acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), the electronic and wetting characteristics of the electrodes can be tailored.  Combining these modified electrodes with p-type organic semiconductors such as 6,13-bis(triisopropyl-silylethynyl) pentacene (TIPS-pentacene), and polymer/small molecule (acene-type) blend semiconductors results in a significant improvement in device performance over the untreated electrodes, yielding high-quality devices with field-effect mobilities > 1 cm2 V-1 s-1.   The effect of this treatment on field-effect transistors incorporating n-type small molecule organic semiconductors will also be discussed.