Formation of self-assembled organosilicon-functionalized quinquethiophene monolayers by fast processing techniques

Different techniques for a relatively fast self-assembled monolayer film formation such as Langmuir-Blodgett (LB), spin-coating, and dip-coating methods have been compared using chloro[11-(5''''-ethyl-2,2':5',2″:5''',2''':5''',2''''-quinquethiophene-5-yl)undecyl]dimethylsilane as a reactive precursor. It was shown that both spin-coating and LB techniques are very promising methods for preparation of highly ordered monolayer films of organosilicon-functionalized quinquethiophene with vertical orientation of oligothiophene fragments, while dip-coating gives only partial coverage. Optimal conditions for complete filling out the substrate surface by the quinquethiophene-containing monolayer by spin-coating and LB methods have been found. Grazing incidence X-ray diffraction measurements confirmed formation of in-plane crystalline order within the monolayer film. Changes in the layer structure were established by X-ray reflectivity and grazing incidence X-ray diffraction methods.