title: Synthesis, monolayer formation, characterization, and nanometer-scale photolithographic patterning of conjugated oligomers bearing terminal thioacetates.
abstract: The synthesis of alpha-thioacetate terminated quaterthiophene and phenylene-thiophene materials, possessing thioacetate, oxetane, and alkyl groups at their omega-termini, is described. After deprotection these molecules were adsorbed onto Au films and the resulting self-assembled monolayers were characterized by X-ray photoelectron spectroscopy (XPS) and friction force microscopy (FFM). FFM indicated that monolayers formed by the dithioacetates had the highest coefficients of friction, followed by the oxetane-terminated adsorbates, with the alkyl-functionalized materials showing the lowest friction coefficients. These data may be understood in terms of differences in molecular packing. The quaterthiophene adsorbates also yielded higher friction coefficients than their phenylene-thiophene counterparts. Micrometer-scale patterns were fabricated by mask-based exposure to 244 nm light, and characterized by FFM. Nanometer-scale patterns were fabricated using near-field exposure and characterized by FFM. The images obtained demonstrated that features of conjugated oligomers with high spatial resolution (59 nm, ca. lambda/4) were achievable.
authors.affiliation: Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
authors.forename: Iain
authors.initials: I
authors.lastname: Barlow
authors.forename: Shuqing
authors.initials: S
authors.lastname: Sun
authors.forename: Graham J
authors.initials: GJ
authors.lastname: Leggett
authors.forename: Michael
authors.initials: M
authors.lastname: Turner