Block‐Copolymer‐Templated Synthesis of Electroactive RuO2‐Based Mesoporous Thin Films

• Published in: Advanced functional materials 2009-06, Vol.19 (12), p.1922-1929
• Main Authors: Sassoye, Capucine, Laberty, Christel, Le Khanh, Hung, Cassaignon, Sophie, Boissière, Cédric, Antonietti, Markus, Sanchez, Clément
• Format: Article
• Language: English
• Subjects: block copolymers; Chemical Sciences; electrodes; Inorganic chemistry; nanostructures; porous materials; thin films
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200801831

RuO2‐based mesoporous thin films of optical quality are synthesized from ruthenium‐peroxo‐based sols using micelle templates made of amphiphilic polystyrene‐polyethylene oxide block copolymers. The mesoporous structure and physical properties of the RuO2 films (mesoporous volume: 30%; pore diameter: ∼30 nm) can be controlled by the careful tuning of both the precursor solution and thermal treatment (150–350 °C). The optimal temperature that allows control of both mesoporosity and nanocristallinity is strongly dependent on the substrate (silicon or fluorine‐doped tin oxide). The structure of the resulting mesoporous films are investigated using X‐ray diffraction, X‐ray photoelectron spectroscopy, and atomic force microscopy. Mesoporous layers are additionally characterized by transmission and scanning electron microscopy and ellipsometry while their electrochemical properties are analyzed via cyclic voltammetry. Thick mesoporous films of ruthenium oxide hydrates, RuO2 · xH2O, obtained using a thermal treatment at 280 °C, exhibit capacitances as high as 1000 ± 100 F g−1 at a scan rate of 10 mV s−1, indicating their potential application as electrode materials. Facile synthesis of RuO2·xH2O mesoporous thin films with controlled pore and particle size is achieved using ruthenium‐peroxo‐based sols and amphiphilic polystyrene‐polyethylene oxide block copolymers. Capacitances of 1000 ± 100 F g−1 were reached by tuning both the mesoporosity and nanocrystallinity of the thin films, demonstrating the potential of such films as electrode materials.