ABSTRACT
The use of a novel inorganic nanoscale cluster (Al[(µ-OH)2Co(NH3)4]3(NO3)6) was investigated for its utility as a precursor for AlCoOx films. Mixed-metal aluminum and cobalt oxide thin films were solution deposited from the novel cluster solution via the spin-coating method on Si (100) and quartz substrates. The films were annealed at increasing temperatures up to 800 °C, and characterization of these films via TEM and XRD confirms binary Co3O4 crystalline phase present in an amorphous Al2O3 network. Films are relatively smooth (Rrms < 4 nm), polycrystalline, and demonstrate a tunable optical response dominated by Co3O4 with two electronic transitions.
ABSTRACT
Large aqueous ions are interesting because they are useful in materials science (for example to generate thin films) but also because they serve as molecular models for the oxide-aqueous mineral interface where spectroscopy is difficult. Here we show that new clusters of the type M[(µ-OH)2 Co(NH3 )4 ]3 (NO3 )6 (M=Al, Ga) can be synthesized using Werner's century-old cluster as a substitutable framework. We substituted Groupâ 13 metals into the hexol Co[(µ-OH)2 Co(NH3 )4 ]36+ ion to make diamagnetic heterometallic ions. The solid-state structure of the hexol-type derivatives were determined by single-crystal XRD and NMR spectroscopy and confirmed that the solid-state structure persists in solution after dissolution into either D2 O or [D6 ]DMSO. Other compositions besides these diamagnetic ions can undoubtedly be made using a similar approach, which considerably expands the number of stable aqueous heteronuclear ions.
