am7b03399_si_001.pdf (1.24 MB)
Balanced Ambipolar Organic Field-Effect Transistors by Polymer Preaggregation
journal contribution
posted on 2017-05-31, 00:00 authored by Lukasz Janasz, Adam Luczak, Tomasz Marszalek, Bertrand G. R. Dupont, Jaroslaw Jung, Jacek Ulanski, Wojciech PisulaAmbipolar
organic field-effect transistors (OFETs) based on heterojunction
active films still suffer from an imbalance in the transport of electrons
and holes. This problem is related to an uncontrolled phase separation
between the donor and acceptor organic semiconductors in the thin
films. In this work, we have developed a concept to improve the phase
separation in heterojunction transistors to enhance their ambipolar
performance. This concept is based on preaggregation of the donor
polymer, in this case poly(3-hexylthiophene) (P3HT), before solution
mixing with the small-molecular-weight acceptor, phenyl-C61-butyric
acid methyl ester (PCBM). The resulting heterojunction transistor
morphology consists of self-assembled P3HT fibers embedded in a PCBM
matrix, ensuring balanced mobilities reaching 0.01 cm2/V
s for both holes and electrons. These are the highest mobility values
reported so far for ambipolar OFETs based on P3HT/PCBM blends. Preaggregation
of the conjugated polymer before fabricating binary blends can be
regarded as a general concept for a wider range of semiconducting
systems applicable in organic electronic devices.