Using a colloidal suspension, electrochemically active tungsten oxide thin films (150 nm) have been prepared via ultrasonic spray deposition using two different current collectors, namely TiN and Pt.

Thin films of amorphous and crystalline perovskite Li 3x La (2/3)-x TiO 3 (LLT) (x = 0.117) are prepared by means of aqueous chemical solution deposition onto rutile TiO 2 thin films as an anode, yielding an electrochemical half-cell. The Li-ion conductivity of the pinhole free, amorphous LLT thin film (90 nm thick) is 3.8 9 10 -8 S cm -1 on Pt and 1.3 9 10 -8 S cm -1 on rutile TiO 2 , while measuring perpendicular to the thin film direction with impedance spectroscopy. Grazing angle attenuated total reflectance-Fourier transform infrared spectroscopy shows that all organic precursor molecules have been decomposed at 500°C. In addition, in situ (heating) X-ray diffraction analysis shows that phase pure crystalline perovskite LLT (x = 0.117) is formed on top of the rutile TiO 2 anode at 700°C. Furthermore, thickness control is possible by varying the precursor solution concentration and the number of deposition cycles. The current study presents a promising synthesis route to develop all-solid-state battery devices based on multi-metal oxide materials using aqueous precursor chemistry.

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a b s t r a c tThin orthorhombic ultra high-k LuFeO 3 (LFO) films on Si 3 N 4 /SiO 2 /Si substrates were obtained by means of aqueous chemical solution deposition (CSD). Prior to thin film deposition, the precursor synthesis, thermal decomposition and crystallization behavior of the bulk material were studied. It was shown that phase-pure hexagonal LFO powder could be formed at 650 • C while a higher temperature of 900 • C was required to obtain the orthorhombic phase. Deposition on SiO 2 /Si resulted in the development of silicates in this temperature range, thus preventing the formation of the orthorhombic LuFeO 3 phase. The use of Si 3 N 4 /SiO 2 /Si as the substrate shifted the silicate formation to higher temperature, allowing the synthesis of phase-pure orthorhombic LuFeO 3 as a thin film at 1000 • C. Impedance spectroscopy analyses confirmed its associated ultra high dielectric constant (>10,000) at room temperature for frequencies lower than or equal to 1 kHz.