Chemical
modification of insulating material surfaces is an important methodology
to improve the performance of organic field-effect transistors (OFETs).
However, few redox-active self-assembled monolayers (SAMs) have been
constructed on gate insulator film surfaces, in contrast to the numerous
SAMs formed on many types of conducting electrodes. In this study,
we report a new approach to introduce a π-conjugated organic
fragment in close proximity to an insulating material surface via
a transition metal center acting as a one-atom anchor. On the basis
of the reported coordination chemistry of a catecholato complex of
Pt(II) in solution, we demonstrate that ligand exchange can occur
on an insulating material surface, affording SAMs on the SiO2 surface derived from a newly synthesized Pt(II) complex containing
a benzothienobenzothiophene (BTBT) framework in the catecholato ligand.
The resultant SAMs were characterized in detail by water contact angle
measurements, X-ray photoelectron spectroscopy, atomic force microscopy,
and cyclic voltammetry. The SAMs served as good scaffolds of π-conjugated
pillars for forming thin films of a well-known organic semiconductor
C8-BTBT (2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene),
accompanied by the engagements of the C8-BTBT molecules with the SAMs
containing the common BTBT framework at the first layer on SiO2. OFETs containing the SAMs displayed improved performance
in terms of hole mobility and onset voltage, presumably because of
the unique interfacial structure between the organic semiconducting
and inorganic insulating layers. These findings provide important
insight into creating new elaborate interfaces through installing
coordination chemistry in solution to solid surfaces, as well as OFET
design by considering the compatibility between SAMs and organic semiconductors.