Mapping of charge distribution in organic field-effect transistors by confocal photoluminescence electromodulation microscopy.

A novel method for mapping the charge density spatial distribution in organic field-effect transistors based on the electromodulation of the photoluminescence is demonstrated. In field-effect transistors exciton quenching is dominated by exciton-charge carrier interaction so that it can be used to map the charge distribution in different operating conditions. From a quantitative analysis of the photoluminescence quenching, the thickness of the charge carrier accumulation layer is derived. The injection of minority charge carriers in unipolar conditions is unexpectedly evidenced, which is not displayed by the electrical characteristics.

Modulation of αvß3- and α5ß1-integrin-mediated adhesion by dehydro-ß-amino acids containing peptidomimetics.

A novel class of low molecular weight ligands of αvß3 and α5ß1 integrins, that possess a dehydro-ß-amino acid as conformationally constrained core, linked to the pharmacophoric moieties mimicking the RGD recognition sequence, have been synthesized through a very simple protocol. Cell adhesion assays and integrin-mediated signaling activation experiments suggested a good affinity of these compounds toward both integrin receptors. Moreover, further elongation with two glycine units allowed to obtain an excellent dual inhibitor. Structural models for αvß3 integrin-ligand binding confirmed that the dehydro-ß-amino derivatives are able to act as an electrostatic clamp by establishing several stabilizing interactions with the receptor.

Thienopyrrolyl dione end-capped oligothiophene ambipolar semiconductors for thin film- and light emitting transistors.

The design, synthesis and structure-property investigation of a new thienopyrrolyl dione substituted oligothiophene material showing reduced band gap energy, low lying LUMO energy level and ambipolar semiconducting behaviour is described.