A method for forming CsPbBr.sub.3 perovskite nanocrystals into a two-dimensional (2D) nanosheet includes providing CsPbBr.sub.3 perovskite nanocrystals; mixing the CsPbBr.sub.3 perovskite nanocrystals into a mixture of a first solvent and a second solvent, to form a solution of the CsPbBr.sub.3 perovskite nanocrystals, the first solvent, and the second solvent; and forming an optoelectronic device by patterning the CsPbBr.sub.3 perovskite nanocrystals into a nanosheet, between first and second electrodes. The first solvent is selected to evaporate before the second solvent.

A flexible photovoltaic device is provided. The flexible photovoltaic device includes a flexible inorganic halide perovskite. The flexible inorganic halide perovskite is free of organic components, has a thickness of greater than or equal to about 1 μm to less than or equal to about 1 nm, and has an average grain size of less than or equal to about 500 nm.

The present invention relates to a material of the formula SnTiO.sub.3 having a crystal structure comprised of layers, wherein the layers comprise Sn(II) ions, Ti(IV) ions and edge-sharing O.sub.6-octahedra, the edge-sharing O.sub.6-octahedra form a sub-layer, the Ti(IV) ions are located within ⅔ of the edge-sharing O.sub.6-octahedra, thus forming edge-sharing TiO.sub.6-octahedra, the edge-sharing TiO.sub.6-octahedra form a honeycomb structure within the sub-layer, the honeycomb structure comprising hexagons with Ti(IV)-vacancies within the hexagons, the Sn(II) ions are located above and below the Ti(IV)-vacancies with respect to the sub-layer, the Ti(IV) ions are optionally substituted with M, M is one or more elements selected from Group 4 and Group 14 elements, and the crystal structure satisfies at least one of the following features (i) and (ii): (i) the Sn(II) ions have a tetrahedral coordination sphere involving three O ions of the layer and the electron lone pair of the Sn(II) ions which is situated at an apical position relative to the three O ions of the layer, (ii) the layers are stacked so that each layer is translated relative to each adjacent layer by a stacking vector S1 or a stacking vector S2, the centers of adjacent hexagons form a parallelogram with a side having a length x and side having a length y, the stacking vector S1 is a combined translation along the side having the length x by ⅔ x and along the side having a lengthy by ⅓ y, the stacking vector S2 is a combined translation along the side having the length x by ⅓ x and along the side having a lengthy by ⅔ y, and the crystal structure comprises layers translated relative to adjacent layers by the stacking vector S1 and layers translated relative to adjacent layers by the stacking vector S2. The present invention is further directed to a material of the formula SnTiO.sub.3 having a tetragonal perovskite-type crystal structure, a method for the preparation of SnTiO.sub.3, a device comprising a ferroelectric material and a use of the material of the formula SnTiO.sub.3 in a ferroelectric element.

Disclosed is a ferromagnetic element-substituted room-temperature multiferroic material having ferromagnetism and ferroelectricity at room temperature, wherein the ferromagnetic element-substituted room-temperature multiferroic material includes a compound of chemical formula 1: <chemical formula 1> (Pb.sub.1-xM.sub.x)Fe.sub.1/2Nb.sub.1/2O.sub.3. In chemical formula 1, M represents a ferromagnetic element, and x represents a number greater than 0 and smaller than 1.

A ceramic electronic component includes: a body including dielectric layers and internal electrodes; and external electrodes disposed on the body and connected to the internal electrodes, wherein the dielectric layer includes a plurality of dielectric crystal grains, and at least one of the plurality of dielectric crystal grains has a core-double shell structure, the double shell includes a first shell surrounding at least a portion of the core and a second shell surrounding at least a portion of the first shell, the first shell includes a first element, one or more of Sn, Sb, Ge, Si, Ga, In, or Zr, and the second shell includes a second element, one or more of Ca or Sr.

The present disclosure discloses an ABO.sub.3 type high-entropy perovskite Ba.sub.x(FeCoNiZrY).sub.0.2O.sub.3-δ electrocatalytic material and a preparation method thereof, belonging to the technical field of electrocatalytic materials. The electrocatalytic material is prepared by taking hydrated cobalt nitrate, hydrated ferric nitrate, hydrated nickel nitrate, barium nitrate, hydrated yttrium nitrate, hydrated zirconium nitrate and polyacrylonitrile staple fibers as raw materials through processes of liquid phase chelation, gelation, calcination, etc. The prepared high-entropy perovskite Ba.sub.x(FeCoNiZrY).sub.0.2O.sub.3-δ electrocatalytic material can release more electrochemical active sites due to its special nanostructure, thus showing better electrocatalytic activity. Meanwhile, by adjusting the stoichiometric ratio of A/B-site metals, the electronic structure change of five metals in a catalytic center and the change of an oxygen vacancy content are realized, and the purpose of adjusting and optimizing the nitrogen reduction performance is achieved, so that the electrocatalytic material has excellent electrocatalytic conversion of nitrogen gas into ammonia gas.

To provide a piezoelectric body film and a piezoelectric element from which an excellent piezoelectric characteristic can be obtained even in a high-temperature environment and a method for manufacturing a piezoelectric element. A piezoelectric body film of the present invention is a piezoelectric body film containing a perovskite-type oxide represented by Formula (1), in which a content q of Nb with respect to the number of all atoms in the perovskite-type oxide and a ratio r of a diffraction peak intensity from a (200) plane to a diffraction peak intensity from a (100) plane of the perovskite-type oxide, which is measured using an X-ray diffraction method, satisfy Formula (2), Formula (1) A.sub.1+δ[(Zr.sub.yTi.sub.1-y).sub.1-xNb.sub.x]O.sub.2, Formula (2) 0.35≤r/q<0.58, in this case, in Formula (1), A represents an A site element containing Pb, x and y each independently represent a numerical value of more than 0 and less than 1, standard values of δ and z each are 0 and 3, but these values may deviate from the standard values as long as the perovskite-type oxide has a perovskite structure, and, in Formula (2), a unit of q is atm %.

Methods for synthesizing chalcogenide perovskites and chalcogenide perovskites synthesized thereby. Such s method includes providing a precursor solution containing a metal precursor, depositing the precursor solution onto a substrate to form a precursor film, and heating the precursor film in the presence of a chalcogen source to form a chalcogenide perovskite. The precursor solution is oxygen-free, and the steps of depositing and heating are conducted in an inert atmosphere.

Disclosed herein are doped perovskite oxides. The doped perovskite oxides may be used as a cathode material in an electrochemical cell to electrochemically generate ammonia from N.sub.2. The doped perovskite oxides may be combined with nitride compounds, for instance iron nitride, to further increase the efficiency of the ammonia production.

Provided are a dielectric ceramic composition having excellent temperature properties and low DC bias dependence in a wide temperature range from room temperature to over 200° C., a method of manufacturing a dielectric ceramic composition, and a multilayer ceramic capacitor.