Abstract: The present invention relates to a method for preparing a stabilised crystalline A/M/X material comprising an oxide of formula [Z]pOq and a compound of formula [A]a[M]b[X]c, wherein [Z] comprises at least one element Z capable of forming an oxide with a band gap of at least 3 eV; p and q are positive numbers; [A] comprises one or more A cations; [M] comprises one or more M cations; [X] comprises one or more X anions; a is an integer from 1 to 6; b is an integer from 1 to 6; and c is an integer from 1 to 18. Often, the stabilised crystalline A/M/X material is a perovskite. The invention also provides a stabilised crystalline A/M/X material, which can be produced by the process of the invention. The invention further provides materials and devices containing the stabilised crystalline A/M/X material of the invention.

Abstract: The present invention relates to a process for producing a layer of a crystalline A/M/X material, which crystalline A/M/X material comprises a compound of formula [A]a[M]b[X]c, wherein: [M] comprises one or more first cations, which one or more first cations are metal or metalloid cations; [A] comprises one or more second cations; [X] comprises one or more halide anions; a is an integer from 1 to 6; b is an integer from 1 to 6; and c is an integer from 1 to 18, wherein the process comprises disposing on a substrate a precursor composition comprising: (a) a first precursor compound comprising a first cation (M), which first cation is a metal or metalloid cation; and (b) a solvent, and wherein the solvent comprises: (i) a non-polar organic solvent which is a hydrocarbon solvent, a chlorohydrocarbon solvent or an ether solvent; and (ii) a first organic amine comprising at least three carbon atoms. Also described are compositions useful in the process of the invention.

Abstract: The invention relates to perovskite compounds which have surprisingly good emission properties, particularly photoluminescent emission properties, in the blue region of the visible spectrum. These perovskites contain a mixture of cations or a mixture of halides, or both. The invention also relates to a photoactive material containing the perovskite species of the invention; to an optoelectronic device containing the photoactive material of the invention; to a method of producing blue light; and to the use of the photoactive material of the invention to emit blue light or as a phosphor.

Abstract: The invention relates to a process for producing a crystalline A/M/X material, which crystalline A/M/X material comprises a compound of formula [A]a[M]b[X]c wherein: [A] comprises one or more A cations; [M] comprises one or more M cations which are metal or metalloid cations; [X] comprises one or more X anions; a is a number from 1 to 6; b is a number from 1 to 6; and c is a number from 1 to 18. The process is capable of producing crystalline A/M/X materials while precisely controlling their stoichiometry, leading to products with finely tunable optical properties such as peak emission wavelength. The invention also relates to process for producing a thin film comprising the crystalline A/M/X material of the invention, and to a thin film obtainable by the process of the invention. An optoelectronic device comprising the thin film is also provided.

Abstract: The present invention relates to a method for preparing a stabilised crystalline A/M/X material comprising an oxide of formula [Z]pOq and a compound of formula [A]a[M]b[X]c, wherein [Z] comprises at least one element Z capable of forming an oxide with a band gap of at least 3 eV; p and q are positive numbers; [A] comprises one or more A cations; [M] comprises one or more M cations; [X] comprises one or more X anions; a is an integer from 1 to 6; b is an integer from 1 to 6; and c is an integer from 1 to 18. Often, the stabilised crystalline A/M/X material is a perovskite. The invention also provides a stabilised crystalline A/M/X material, which can be produced by the process of the invention. The invention further provides materials and devices containing the stabilised crystalline A/M/X material of the invention.