This paper reports on two sets of data. In the first one, organic thin-film transistors (OTFTs) where fabricated
by vapor depositing a pentacene layer on a gate dielectric made of alumina. The devices divide in two sets,
depending on whether the alumina surface was or was not modified with a self-assembled monolayer (SAM) of
eicosanoic acid. Atomic force microscopy (AFM) images show that the presence of the SAM strongly reduces the
size of the crystal grains. A careful analysis of the current-voltage characteristics of the devices, which includes
the use of the Transfer Line Method (TLM), allowed the extraction of the gate voltage (<i>V<sub>G</sub></i>) dependent mobility
corrected for contact resistance. A remarkable feature is that the mobility decreases with <i>V<sub>G</sub></i> at high gate bias,
which is interpreted by assuming that the mobility in the layer close to the insulator-semiconductor interface is
substantially lower than that in the bulk of the film. Modeling the charge distribution in the conducting channel
allowed us to extract the bulk mobility, which is found to saturate at around 5 cm<sup>2</sup>/Vs in SAM-modified devices
and 3 cm<sup>2</sup>/Vs in devices with bare alumina. The difference is interpreted in terms of more or less defective grains.
The second set of results deals with a transistor, in which the active element is reduced to a single monomolecular
layer. This was achieved by using a SAM of a bifunctional molecule comprising a quaterthiophene moiety linked
to a short alkyl chain. AFM images of the SAM after various adsorption times show that the size of the well-organized
domains is around 25 ± 5 nm. Working transistors could only be realized by reducing the channel
length <i>L</i> down to a magnitude comparable to that of the domain size, which was achieved with the help of
e-beam lithography. In one occasion, well-defined current-voltage characteristics was recorded, which allowed to
extract a gate-voltage independent mobility of 0.0035 cm<sup>2</sup>/Vs.
Five new elecdtroluminescent compounds based ont tris(8-quinolinolate)Al(III) and lithium quinolate with thiophene substituents at C-2 and C-5 position were synthesized and characterized. Lithium complexes showed blue emission, whereas aluminum complexes gave green fluorescence in solution. Double-layer devices were fabricated and found to emit light with brightness in excess of 3000 cd/m<sup>2</sup> with an efficiency of 1.36 cd/A. These preliminarily electroluminescent results demonstrate that the novel oligothiophene substituted 8-hydroxyquinolines are promising emissive and electron transport materials for organic electroluminescent devices.