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 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 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 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 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 provides a process for producing a passivated semiconductor, which process comprises treating a semiconductor with a passivating agent, wherein: the semiconductor comprises a crystalline compound comprising: (i) one or more first cations (A); (ii) one or more metal cations (M); and (iii) one or more anions (X); and the passivating agent comprises a compound comprising an oxygen-oxygen single bond. A composition and the use of a passivating agent are also provided.

Abstract: The present invention relates to a process for producing a layer of crystalline A/M/X material, 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, wherein the solvent comprises; (i) acetonitrile, propionitrile, acetone or a mixture thereof; and (ii) an alkylamine. The invention also relates to a composition comprising: (i) a compound of formula MXn, (ii) a compound of formula AX, (iii) acetonitrile, propionitrile, acetone or a mixture thereof; and (iv) an alkylamine of formula RANH2, wherein RA is a C1-8 alkyl group.

Abstract: An optical sensor (1) for detecting a chemical species includes a substrate (3), a mesoporous matrix (5) disposed on the substrate, and a microporous matrix (7) disposed within the mesoporous matrix. The microporous matrix (7) includes an indicator dye (9) dispersed therein, the indicator dye (9) exhibiting changes in its optical properties in response to the presence of the chemical species. This arrangement significantly increases the amount of dye present, while allowing the medium to be analyzed greater access through the porous structure, thereby increasing the performance of the sensor.

Abstract: The present invention relates to a crystalline compound comprising: (i) Cs+ (caesium); (ii) (H2N—C(H)—NH2)+ (formamidinium); (iii) one or more metal or metalloid dications [B]; and (iv) two or more different halide anions [X]. The invention also relates to a semiconductor device comprising a semiconducting material, which semiconducting material comprises the crystalline compound. The invention also relates to a process for producing a layer of the crystalline compound.

Abstract: The present invention relates to a process for producing a layer of crystalline A/M/X material, 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, wherein the solvent comprises; (i) acetonitrile, propionitrile, acetone or a mixture thereof; and (ii) an alkylamine. The invention also relates to a composition comprising: (i) a compound of formula MXn, (ii) a compound of formula AX, (iii) acetonitrile, propionitrile, acetone or a mixture thereof; and (iv) an alkylamine of formula RANH2, wherein RA is a C1-8 alkyl group.

Abstract: The present invention relates to a crystalline compound comprising: (i) Cs+ (caesium); (ii) (H2N—C(H)?NH2)+ (formamidinium); (iii) one or more metal or metalloid dications [B]; and (iv) two or more different halide anions [X]. The invention also relates to a semiconductor device comprising a semiconducting material, which semiconducting material comprises the crystalline compound. The invention also relates to a process for producing a layer of the crystalline compound.

Abstract: Disclosed is an optical sensor (1) for detecting a chemical species, including: a substrate (3); a mesoporous matrix (5) disposed on the substrate; a microporous matrix (7) disposed within the mesoporous matrix, the microporous matrix (7) including an indicator dye (9) dispersed therein, the indicator dye (9) exhibiting changes in its optical properties in response to the presence of the chemical species.

Abstract: The assembly is made up of: a) a support including a mesoporous coating whose pores have an average diameter dimensioned so as to enable molecules from the family of cyanines to penetrate them, and b) a layer of molecules from the family of cyanines and organized into J-aggregates within the pores of the coating. The assembly moreover includes Quantum Dots located within the same pores as those containing the J-aggregates, the Quantum Dots maintaining J-aggregates structure. A method for producing such an assembly is also described.

Abstract: The assembly is made up of: a) a support including a mesoporous coating whose pores have an average diameter dimensioned so as to enable molecules from the family of cyanines to penetrate them, and b) a layer of molecules from the family of cyanines and organized into J-aggregates within the pores of the coating. The assembly moreover includes Quantum Dots located within the same pores as those containing the J-aggregates, the Quantum Dots maintaining J-aggregates structure. A method for producing such an assembly is also described.

Abstract: A light emissive or photovoltaic device comprising: a cathode structure for injecting electrons, the cathode structure having one or more constituent regions; an anode structure for injecting holes, the anode structure having one or more constituent regions; and an organic light emissive component located between the anode structure and the cathode structure; the refractive indices and the thicknesses of the or each constituent region of the cathode and anode structures and of the light emissive component being such that the emission or absorption spectrum of the device is substantially angularly dependent.

Abstract: A light emissive or photovoltaic device comprising: a cathode structure for injecting electrons, the cathode structure having one or more constituent regions; an anode structure for injecting holes, the anode structure having one or more constituent regions; and an organic light emissive component located between the anode structure and the cathode structure; the refractive indices and the thicknesses of the or each constituent region of the cathode and anode structures and of the light emissive component being such that the emission or absorption spectrum of the device is substantially angularly dependent.