The present disclosure relates to a method that includes applying a first perovskite precursor solution to a substrate to form a first liquid film of the first perovskite precursor solution on the substrate; from the first liquid film, forming a first intermediate solid perovskite layer on the substrate; repeating at least once, both the applying and the forming, resulting in the creation of at least one additional intermediate solid perovskite layer; and treating a last intermediate solid perovskite layer, resulting from the at least one additional applying and the at least one additional forming, to create a final solid perovskite layer.

Disclosed are a metal halide perovskite light-emitting material with controlled defects and wavelength converting body having the same, and light-emitting device. Monvalent organic cation (A.sub.2) contained in the perovskite nanocrystal can stabilize the perovskite nanocrystal and suppress the generation of defects in the crystal due to the entropy effect. Remnant A.sub.2 cations not included in the perovskite nanocrystal form a structure surrounding the perovskite nanocrystal particles, and passivate defects generated on the surface of the perovskite nanocrystal particles. Photoluminescence quantum efficiency, photoluminescence lifetime, and stability are improved through passivation of defects, and the metal halide perovskite light-emitting material can be effectively used in a light-emitting layer or a wavelength conversion layer of a light-emitting device.

The present invention relates to highly polarizable 3D organic perovskites of the general formula ABX.sub.3, prepared by introducing halogen functional groups in the A-site cation (in which the A and B sites are occupied by organic cations and the X site is a monovalent non-metallic counterion). The (DCl)(NH.sub.4)(BF.sub.4).sub.3 crystal exhibits a strong linear electrooptic (EO) effect with an effective EO coefficient of 20 pmV.sup.−1, which is 10 times higher than that of metal halide perovskites. These 3D organic perovskites are solution processed and compatible with silicon, and illustrate the potential of rationally-designed all-organic perovskites for use in on-chip modulators, electro-optic devices, piezoelectric devices, or silicon photonics devices.

A solid electrolyte including: an oxide represented by Formula 1
Li.sub.yM.sub.zHfO.sub.3-x  Formula 1
wherein, in Formula 1, M is a divalent element, a trivalent element, or a combination thereof, and 0≤x<3, 0<y<1, and 0<z<1.

Described herein are materials comprising (1) a monomer or a polymer; (2) perovskite quantum dots interspersed in the monomer or the polymer, each of the perovskite quantum dots independently having the formula:

Cs.sub.a(MA).sub.b(FA).sub.cRb.sub.dPb.sub.pSn.sub.rBi.sub.sCl.sub.xBr.sub.yI.sub.z,

wherein: MA is CH.sub.3NH.sub.3; FA is HC(NH.sub.2).sub.2; a, b, c, and d are each independently a number from 0 to 1, provided that the sum of a, b, c, and d is 1; p, r, and s are each independently a number from 0 to 1, provided that the sum of p, r, and s is 1; and x, y, and z are each independently a number from 0 to 3, provided that the sum of x, y, and z is 3; and (3) an additive interspersed in the monomer or the polymer, the additive comprising: a halide-based additive; a light scattering agent having the formula: M.sub.2O.sub.3, wherein M is, at each occurrence, independently, a metal, provided that at most one instance of M is a group 13 element; or both. Also described are devices comprising such materials, as well as methods of forming such materials.

An antimicrobial material including a substrate and an antimicrobial mixed metal oxide, mixed metal sulfide, or mixed metal oxysulfide in and/or on the substrate is described, as well as antimicrobial coating materials and coatings formed therefrom. The antimicrobial material may be constituted in an antimicrobial surface of a surface-presenting substrate, to combat transmission and spread of microbial disease, e.g., disease mediated by microbial pathogens such as bacteria, viruses, and fungi. Antimicrobial mixed metal oxide, mixed metal sulfide, or mixed metal oxysulfide as described may be contacted with microorganisms to effect inactivation thereof.

Bandgap-tunable perovskite compositions are provided having the formula CsPb(A).sub.xB.sub.y).sub.3, wherein A and B are each a halogen. The mixed halide perovskite composition has a morphology which suppresses phase segregation to stabilize a tuned bandgap of the mixed halide perovskite composition. For example, the perovskite may be in the form of nanocrystals embedded in a non-perovskite matrix, which, for example, may have the formula Cs.sub.4Pb(A).sub.xB.sub.y).sub.6, wherein A and B are each a halogen. Solar cells and light-emitting diodes comprising the mixed perovskite compositions are also provided.

A method of forming a metal oxide material having a rod shape or polyhedral nanostructure includes preparing a first reverse micro-emulsion system comprising an aqueous precipitating agent dispersion and a second reverse micro-emulsion system containing an aqueous metal salt dispersion; combining the micro-emulsions together to initiate a reaction; allowing the reaction to continue to form a product mixture comprising a metal oxide gel and aqueous media; separating the metal oxide gel from the aqueous media; collecting the metal oxide gel; and calcining the metal oxide gel to form the metal oxide material. The metal oxide material corresponds to the chemical formula of La.sub.2M.sub.xNi.sub.1-xO.sub.4, Pr.sub.2-yA.sub.yNiO.sub.4, or La.sub.2-zD.sub.zNiO.sub.4, wherein M is copper, cobalt, iron, manganese, chromium, aluminum, or platinum; A is lanthanum or neodymium; D is calcium, barium or strontium; x ranges from 0 to 1; y ranges from 0 to 2; and z ranges from 0 to 0.25.

A method of forming a polyolefin-perovskite nanomaterial composite which contains oriented electrically and thermally conductive pathways. The method involves milling a polyolefin with particles of a perovskite nanomaterial, molding to forma composite plate, and subjecting the composite plate to an AC voltage. The AC voltage forms oriented electrically and thermally conductive pathways by partial dielectric breakdown of the composite. The presence of the oriented electrically and thermally conductive pathways gives the polyolefin-perovskite nanomaterial electrical and thermal conductivity and dielectric permittivity higher than the polyolefin alone.

A method for producing a solid composition according to the present disclosure includes producing an oxide to be converted into a first functional ceramic by reacting with an oxoacid compound, and mixing the oxide, the oxoacid compound, and a second functional ceramic that is different from the first functional ceramic. The oxoacid compound preferably contains at least one of a nitrate ion and a sulfate ion as an oxoanion.