The influence of solution-processed small-molecule semiconductor to control of OFET properties

conference paper

English

The aim of this study is to elucidate the influence of metal electrode and dielectric surface modifications on the performance of 3,6-bis(5-(benzofuran-2-yl)thiophen-2-yl)-2,5-bis(2-ethylhexyl) pyrrolo[3,4-c]pyrrole-1,4-dione (referred as DPP(TBFu)2) based organic field effect transistors (OFETs). The performance of OFETs is dependent on the charge carrier injection from contact and their transport within the first organic semiconductor (OSC) monolayers at the interface with the gate dielectric. The application of organosilane self-assembled monolayers (SAMs) on gate-dielectrics (SiO2) induced two orders of magnitude increase of charge carrier mobility. The processing of the transistor electrodes aims to reduce the contact resistance (Rc) at the interface with the OSC, which influences injection and extraction of charge carriers. In the case of the hole injection barrier (p-type OSCs), i.e., the difference between the ionization potential of OSC and the Fermi level of metal electrode, the contact resistance can be reduced by change of the metal (usually gold) work function with the help of charge redistribution at metal surface induced by fluorinated thiol SAMs. In this contribution, we lowered the contact resistance by eliminating the adsorbed impurities on the gold electrode and by introduction of SAMs of penthafluorothiophenol (PFTP). The highest charge carrier mobility 5.5∙10-3 cm2V-1s-1, reported so far, was achieved due to the cumulative effect of the reduction of the hole injection barrier by PFTP and treatment of the gate dielectric by hexamethyldisilazane (HMDS).

Organic Semiconductors, OFET, Contact Resistance, SAM, PFTP, HMDS

STŘÍTESKÝ, S., WEITER, M., VALA, M.

2014

4. 12. 2014

Vysoké učení technické v Brně, Fakulta chemická, Purkyňova 464/118, 612 00 Brno

978-80-214-5077-6

Studentská odborná konference Chemie je život 2014

první

93

93

104