Colloidal perovskite nanoplatelets can provide a material platform, with tunability extending from the deep UV, across the visible, into the near-IR. The high degree of spectral tunability can be achieved through variation of the cation, metal, and halide composition as well as nanoplatelet thickness.

Colloidal perovskite nanoplatelets can provide a material platform, with tunability extending from the deep UV, across the visible, into the near-IR. The high degree of spectral tunability can be achieved through variation of the cation, metal, and halide composition as well as nanoplatelet thickness.

A method of making a perovskite layer includes providing a flexible substrate; providing a perovskite solution comprising an initial amount of solvent and perovskite precursor materials and a total solids concentration between 30 percent and 70 percent by weight of its saturation concentration; depositing the perovskite solution on the substrate; removing a first portion of the solvent from the deposited perovskite solution and increasing the total solids concentration of the perovskite solution to at least 75 percent of its saturation concentration with a first drying step; and removing a second portion of the solvent from the deposited perovskite solution with a second drying step having a higher rate of solvent evaporation that causes saturation and a conversion reaction in the deposited perovskite solution resulting in perovskite crystal formation or formation of a perovskite intermediate phase, wherein the first drying step dwell time is at least 5 times longer than the second drying step dwell time. A continuous inline method for production of photovoltaic devices at high speed, and a perovskite solution for use in making a uniform Perovskite layer at high speed to enable low cost production of high efficiency Perovskite devices are also described.

A method of making a perovskite layer includes providing a flexible substrate; providing a perovskite solution comprising an initial amount of solvent and perovskite precursor materials and a total solids concentration between 30 percent and 70 percent by weight of its saturation concentration; depositing the perovskite solution on the substrate; removing a first portion of the solvent from the deposited perovskite solution and increasing the total solids concentration of the perovskite solution to at least 75 percent of its saturation concentration with a first drying step; and removing a second portion of the solvent from the deposited perovskite solution with a second drying step having a higher rate of solvent evaporation that causes saturation and a conversion reaction in the deposited perovskite solution resulting in perovskite crystal formation or formation of a perovskite intermediate phase, wherein the first drying step dwell time is at least 5 times longer than the second drying step dwell time. A continuous inline method for production of photovoltaic devices at high speed, and a perovskite solution for use in making a uniform Perovskite layer at high speed to enable low cost production of high efficiency Perovskite devices are also described.

The present disclosure relates to a composition that includes a perovskite having a stoichiometry comprising A.sub.1-xFA.sub.xSn.sub.1-yB.sub.y(I.sub.1-zX.sub.z).sub.3, where A is a first cation, B is a second cation, X is a halide, and 0.5≤x≤0.9, 0.5≤y≤0.9, and 0≤z≤1. In some embodiments of the present disclosure, A may include at least one of cesium, guanidinium, and/or methylammonium. In some embodiments of the present disclosure, X may include at least one of bromide and/or chloride. In some embodiments of the present disclosure, z may be equal to zero.

The present disclosure relates to a composition that includes a perovskite having a stoichiometry comprising A.sub.1-xFA.sub.xSn.sub.1-yB.sub.y(I.sub.1-zX.sub.z).sub.3, where A is a first cation, B is a second cation, X is a halide, and 0.5≤x≤0.9, 0.5≤y≤0.9, and 0≤z≤1. In some embodiments of the present disclosure, A may include at least one of cesium, guanidinium, and/or methylammonium. In some embodiments of the present disclosure, X may include at least one of bromide and/or chloride. In some embodiments of the present disclosure, z may be equal to zero.

The invention provides an optoelectronic device comprising a mixed-anion perovskite, wherein the mixed-anion perovskite comprises two or more different anions selected from halide anions and chalcogenide anions. The invention further provides a mixed-halide perovskite of the formula (I) [A][B][X].sub.3 wherein: [A] is at least one organic cation; [B] is at least one divalent metal cation; and [X] is said two or more different halide anions. In another aspect, the invention provides the use of a mixed-anion perovskite as a sensitizer in an optoelectronic device, wherein the mixed-anion perovskite comprises two or more different anions selected from halide anions and chalcogenide anions. The invention also provides a photosensitizing material for an optoelectronic device comprising a mixed-anion perovskite wherein the mixed-anion perovskite comprises two or more different anions selected from halide anions and chalcogenide anions.

The invention provides an optoelectronic device comprising a mixed-anion perovskite, wherein the mixed-anion perovskite comprises two or more different anions selected from halide anions and chalcogenide anions. The invention further provides a mixed-halide perovskite of the formula (I) [A][B][X].sub.3 wherein: [A] is at least one organic cation; [B] is at least one divalent metal cation; and [X] is said two or more different halide anions. In another aspect, the invention provides the use of a mixed-anion perovskite as a sensitizer in an optoelectronic device, wherein the mixed-anion perovskite comprises two or more different anions selected from halide anions and chalcogenide anions. The invention also provides a photosensitizing material for an optoelectronic device comprising a mixed-anion perovskite wherein the mixed-anion perovskite comprises two or more different anions selected from halide anions and chalcogenide anions.

There is provided a method of preparing formamidinium lead halide perovskite quantum dots having a photoluminescence quantum yield higher than before. The disclosed method comprises steps of: preparing a lead halide solution by dissolving lead halide (II), oleic acid and oleylamine in a nonpolar solvent; preparing a formamidinium solution by dissolving formamidine acetate salt and oleic acid in a nonpolar solvent; mixing the formamidinium solution and the lead halide solution to form quantum dots; and centrifuging the mixed solution to obtain sediment; dispersing the sediment in a nonpolar solvent to prepare a crude quantum dot solution; mixing the crude quantum dot solution with methyl acetate; and centrifuging the crude quantum dot solution mixed with the methyl acetate to obtain sediment as purified quantum dots. The durable quantum dots are stably formed by injecting the lead halide solution into the formamidinium solution heated at 60° C.-90° C.

There is provided a method of preparing formamidinium lead halide perovskite quantum dots having a photoluminescence quantum yield higher than before. The disclosed method comprises steps of: preparing a lead halide solution by dissolving lead halide (II), oleic acid and oleylamine in a nonpolar solvent; preparing a formamidinium solution by dissolving formamidine acetate salt and oleic acid in a nonpolar solvent; mixing the formamidinium solution and the lead halide solution to form quantum dots; and centrifuging the mixed solution to obtain sediment; dispersing the sediment in a nonpolar solvent to prepare a crude quantum dot solution; mixing the crude quantum dot solution with methyl acetate; and centrifuging the crude quantum dot solution mixed with the methyl acetate to obtain sediment as purified quantum dots. The durable quantum dots are stably formed by injecting the lead halide solution into the formamidinium solution heated at 60° C.-90° C.