A piezoelectric stack, including: a substrate; an electrode film; and a piezoelectric film comprising an alkali niobium oxide of a perovskite structure represented by a composition formula of (K.sub.1-xNa.sub.x)NbO.sub.3 (0<x<1), wherein an average light transmittance through the piezoelectric film in a wavelength region of visible light and near-infrared ray is 65% or more.

Conducting metal oxide and nitride nanoparticles that can be used in fuel cell applications. The metal oxide nanoparticles are comprised of for example, titanium, niobium, tantalum, tungsten and combinations thereof. The metal nitride nanoparticles are comprised of, for example, titanium, niobium, tantalum, tungsten, zirconium, and combinations thereof. The nanoparticles can be sintered to provide conducting porous agglomerates of the nanoparticles which can be used as a catalyst support in fuel cell applications. Further, platinum nanoparticles, for example, can be deposited on the agglomerates to provide a material that can be used as both an anode and a cathode catalyst support in a fuel cell.

Conducting metal oxide and nitride nanoparticles that can be used in fuel cell applications. The metal oxide nanoparticles are comprised of for example, titanium, niobium, tantalum, tungsten and combinations thereof. The metal nitride nanoparticles are comprised of, for example, titanium, niobium, tantalum, tungsten, zirconium, and combinations thereof. The nanoparticles can be sintered to provide conducting porous agglomerates of the nanoparticles which can be used as a catalyst support in fuel cell applications. Further, platinum nanoparticles, for example, can be deposited on the agglomerates to provide a material that can be used as both an anode and a cathode catalyst support in a fuel cell.

A piezoelectric body contains potassium, sodium, and niobium, and has a perovskite structure. A Raman shift of peaks assigned to A.sub.1g obtained by performing Raman spectroscopic analysis on a plurality of measurement regions is 400 cm.sup.−1 or more and 700 cm.sup.−1 or less. A difference between a maximum value and a minimum value of the Raman shift among the peaks in the plurality of measurement regions is 11.0 cm.sup.−1 or less.

A metal oxide nanoparticle comprises a metal oxide core of formula M.sub.2O.sub.5, wherein M is tantalum (V) or niobium (V) and alkylsiloxane ligands bonded to the metal oxide core. The alkylsiloxane ligands are selected from the group consisting of isobutylsiloxane, allylsiloxane, vinylsiloxane, n-propyl siloxane, n-butylsiloxane, sec-butyl siloxane, tert-butyl siloxane, phenylsiloxane, n-octylsiloxane, isooctylsiloxane n-dodecyl siloxane, 4 -(trimethyl silyl)phenylsiloxane, para-tolylsiloxane, 4-fluorophenyl siloxane, 4 -chlorophenyl siloxane, 4-bromophenyl siloxane, 4-iodophenylsiloxane, 4-cyanophenyl siloxane, benzylsiloxane, methylsiloxane, ethylsiloxane, 4-(trifluoromethyl)phenylsiloxane, 4 -ammoniumbutylsiloxane, and any combination thereof.

A metal oxide nanoparticle comprises a metal oxide core of formula M.sub.2O.sub.5, wherein M is tantalum (V) or niobium (V) and alkylsiloxane ligands bonded to the metal oxide core. The alkylsiloxane ligands are selected from the group consisting of isobutylsiloxane, allylsiloxane, vinylsiloxane, n-propyl siloxane, n-butylsiloxane, sec-butyl siloxane, tert-butyl siloxane, phenylsiloxane, n-octylsiloxane, isooctylsiloxane n-dodecyl siloxane, 4 -(trimethyl silyl)phenylsiloxane, para-tolylsiloxane, 4-fluorophenyl siloxane, 4 -chlorophenyl siloxane, 4-bromophenyl siloxane, 4-iodophenylsiloxane, 4-cyanophenyl siloxane, benzylsiloxane, methylsiloxane, ethylsiloxane, 4-(trifluoromethyl)phenylsiloxane, 4 -ammoniumbutylsiloxane, and any combination thereof.

The embodiments herein relate to electrochromic stacks, electrochromic devices, and methods and apparatus for making such stacks and devices. In various embodiments, an anodically coloring layer in an electrochromic stack or device is fabricated to include nickel-tungsten-niobium-oxide (NiWNbO). This material is particularly beneficial in that it is very transparent in its clear state.

[Problem] Provided is an oxide dielectric having superior properties, and a solid state electronic device (for example, a high pass filter, a patch antenna, a capacitor, a semiconductor device, or a microelectromechanical system) including the oxide dielectric.

[Solution] The oxide layer 30 according to the present invention includes an oxide (possibly including inevitable impurities) consisting essentially of bismuth (Bi) and niobium (Nb) and having a crystal phase of the pyrochlore-type crystal structure, in which the number of atoms of the above niobium (Nb) is 1.3 or more and 1.7 or less when the number of atoms of the above bismuth (Bi) is assumed to be 1.

[Problem] Provided is an oxide dielectric having superior properties, and a solid state electronic device (for example, a high pass filter, a patch antenna, a capacitor, a semiconductor device, or a microelectromechanical system) including the oxide dielectric.

[Solution] The oxide layer 30 according to the present invention includes an oxide (possibly including inevitable impurities) consisting essentially of bismuth (Bi) and niobium (Nb) and having a crystal phase of the pyrochlore-type crystal structure, in which the number of atoms of the above niobium (Nb) is 1.3 or more and 1.7 or less when the number of atoms of the above bismuth (Bi) is assumed to be 1.

Processes for preparing a niobate material include the following steps: (i) providing a niobium-containing source; (ii) providing a transitional metal source (TMS), a post-transitional metal source (PTMS), or both; (iii) dissolving (a) the niobium-containing source, and (b) the TMS, the PTMS, or both in an aqueous medium to form an intermediate solution; (iv) forming an intermediate paste by admixing an inert support material with the intermediate solution; (v) optionally coating the intermediate paste on a support substrate; and (vi) removing the inert support material by subjecting the intermediate paste to a calcination process and providing a transition-metal-niobate (TMN) and/or a post-transition-metal-niobate (PTMN). Anodes including a TMN and/or PTMN are also provided.