Oligothiophene-based nanostructures: from solution to solid-state aggregates

The possibility to develop optoelectronic devices with improved properties by controlling the degree of organization at the mol. level of org. materials has been driving the design of new p-conjugated systems. In particular, the organization by self-assembling processes (p-p interactions, hydrogen bonding) of well-defined oligomeric systems such as disubstituted oligothiophene derivs. has been demonstrated as a promising approach to conjugated materials with a high degree of structural order of the constituent building blocks. Here, tapping-mode at. force microscopy is used to investigate the morphologies of (i) thin deposits made from assembly of thiophene-based oligomers starting from molecularly dissolved solns. or (ii) aggregates already formed in soln. In order to understand the results in terms of supramol. organization, comparisons with mol. modeling simulations are performed. During the self-assembly processes, the interplay between the conjugated mols., the solvent, and the substrate surface is of primary importance. Depending on the interactions between the mols. and the substrate, one-dimensional (nanowires) or two-dimensional (platelets) objects can be generated. The self-organization of conjugated building blocks in soln. or in solid-state on surfaces represents a starting point for the construction of mol. electronics or even circuits, through surface patterning with nanometer-sized objects. [on SciFinder (R)