title: Intercalative poly(carbazole) precursor electropolymerization within hybrid nanostructured titanium oxide ultrathin films.
abstract: A protocol for nanostructuring and electropolymerization of a hybrid semiconductor polycarbazole-titanium oxide ultrathin film is described. Ultrathin (<100 nm) films based on polycarbazole precursor polyelectrolytes and titanium oxide (TiOx) have been fabricated by combining the layer-by-layer (LbL) and surface sol-gel layering techniques. Film growth was followed and confirmed through UV-vis spectroscopy, ellipsometry and quartz crystal microbalance with dissipation (QCM-D). Subsequent anodic electrochemical oxidation of the carbazole pendant units afforded a conjugated polymer network (CPN) film within intercalating TiOx layers of cross-linked and π-conjugated carbazole units. Cyclic voltammetry (CV), UV-vis, and fluorescence spectroscopy measurements confirmed this process. The LbL-driven polyelectrolyte deposition process resulted in a quantified electrochemical response, proportional to the number of layers, while the TiOx acted as a dielectric spacer limiting electron transfer kinetics and attenuating energy transfer in fluorescence. Electro-optical properties were compared with other polycarbazole thin film materials with respect to bandgap energy (Eg). The straightforward protocol in film nanostructuring and barrier/dielectric properties of the inorganic oxide slab (denoted here as, TiOx) should enable applications in organic light-emitting diodes (OLEDs), dielectric mirrors, planar waveguides, and photovoltaic devices for these hybrid ultrathin films.
authors.affiliation: Department of Chemistry and Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-5003, United States.
authors.forename: Antonio F
authors.initials: AF
authors.lastname: Frau
authors.forename: Nicel C
authors.initials: NC
authors.lastname: Estillore
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Fulghum
authors.forename: Rigoberto C
authors.initials: RC
authors.lastname: Advincula
mesh_terms: D002227:Carbazoles / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D004595:Electroplating / Q000379:methods; D007364:Intercalating Agents / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008567:Membranes, Artificial; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D002227:Carbazoles; D007364:Intercalating Agents; D046911:Macromolecular Substances; D008567:Membranes, Artificial; C041514:carbazole; C009495:titanium dioxide; D014025:Titanium