Polyoxoniobates as molecular building blocks in thin films
in Dalton Transactions, 2021, 50, 16030-16038. Link
Abstract: Niobium oxide thin films have been prepared by spin-coating aqueous solutions of tetramethylammonium salts of the isostructural polyoxometalate clusters [Nb10O28]6- , [TiNb10O28]7- and [Ti2Nb8O28]8- onto silicon wafers, and annealing them. The [Nb10O28]6- cluster yields films of Nb2O5 in the orthorhombic and monoclinic crystal phases when annealed at 800 °C and 1,000 °C, respectively, whereas the [TiNb10O28]7- and [Ti2Nb8O28]8- clusters yield the monoclinic crystal phases of Ti2Nb12O29 and TiNb2O7 (titanium-niobium oxides) in different ratios. We also demonstrate a protocol for depositing successive layers of metal oxide films. Finally, we explore factors affecting the roughness of the films.