A method of forming a combinatorial mixed halide perovskite library can include depositing an array of halide perovskite particles on a substrate. The method further includes exposing the array of halide perovskites to a laser to from defects in each of or a selected portion of the halide perovskite particles. The exposure conditions are modified across the array to generate a variation of defect concentration in the halide perovskite particles in the array. The defect containing halide perovskites are then exposed to an ion exchange solution and either anion exchanged or cation exchanged to thereby form a mixed halide perovskite particle.

A method of forming a combinatorial mixed halide perovskite library can include depositing an array of halide perovskite particles on a substrate. The method further includes exposing the array of halide perovskites to a laser to from defects in each of or a selected portion of the halide perovskite particles. The exposure conditions are modified across the array to generate a variation of defect concentration in the halide perovskite particles in the array. The defect containing halide perovskites are then exposed to an ion exchange solution and either anion exchanged or cation exchanged to thereby form a mixed halide perovskite particle.

A method for synthesis of halide salts of the general formula: Z.sup.n+X.sup..sub.n. The method including reacting a first reactant being formate salt with a second reactant being a diatom halogen: X.sub.2.

A method for synthesis of halide salts of the general formula: Z.sup.n+X.sup..sub.n. The method including reacting a first reactant being formate salt with a second reactant being a diatom halogen: X.sub.2.

A method for preparing photoactive perovskite materials. The method comprises the steps of: introducing a lead halide and a first solvent to a first vessel and contacting the lead halide with the first solvent to dissolve the lead halide to form a lead halide solution, introducing a Group 1 metal halide a second solvent into a second vessel and contacting the Group 1 metal halide with the second solvent to dissolve the Group 1 metal halide to form a Group 1 metal halide solution, and contacting the lead halide solution with the Group 1 metal halide solution to form a thin-film precursor ink. The method further comprises depositing the thin-film precursor ink onto a substrate, drying the thin-film precursor ink to form a thin film, annealing the thin film; and rinsing the thin film with a salt solution.

A method for preparing photoactive perovskite materials. The method comprises the steps of: introducing a lead halide and a first solvent to a first vessel and contacting the lead halide with the first solvent to dissolve the lead halide to form a lead halide solution, introducing a Group 1 metal halide a second solvent into a second vessel and contacting the Group 1 metal halide with the second solvent to dissolve the Group 1 metal halide to form a Group 1 metal halide solution, and contacting the lead halide solution with the Group 1 metal halide solution to form a thin-film precursor ink. The method further comprises depositing the thin-film precursor ink onto a substrate, drying the thin-film precursor ink to form a thin film, annealing the thin film; and rinsing the thin film with a salt solution.

A method of forming a halide perovskite nanocrystal array having a plurality of halide perovskite nanocrystals arranged in a pattern can include coating an array of pens with a first ink comprising at least one first perovskite precursor having the formula AX and at least one second perovskite precursor having the formula BX.sub.2 dissolved in a solvent. A is a cation, B is a metal, and X and X are each a halogen. The method further includes contacting a substrate with the coated pen array to thereby deposit the first ink indias a pattern of printed indicia on the substrate. The printed indicia form nanoreactors on the substrate and a halide perovskite nanocrystal nucleates and grows within each nanoreactor to form the halide perovskite nanocrystal array.

A method of forming a halide perovskite nanocrystal array having a plurality of halide perovskite nanocrystals arranged in a pattern can include coating an array of pens with a first ink comprising at least one first perovskite precursor having the formula AX and at least one second perovskite precursor having the formula BX.sub.2 dissolved in a solvent. A is a cation, B is a metal, and X and X are each a halogen. The method further includes contacting a substrate with the coated pen array to thereby deposit the first ink indias a pattern of printed indicia on the substrate. The printed indicia form nanoreactors on the substrate and a halide perovskite nanocrystal nucleates and grows within each nanoreactor to form the halide perovskite nanocrystal array.

The on-demand formation of Lewis base molecules for fabricating efficient and stable formamidinium lead iodide (FAPbI.sub.3)-based perovskite solar cells (PSCs). Semicarbazide hydrochloride (SECl) is incorporated as an additive in the perovskite precursor, which deprotonates to form semicarbazide (SE) molecules when needed to stabilize the intermediate phase. SE molecules protonate again to form SECl salt when they must be removed rapidly to accelerate the transition from the intermediate phase to the photovoltaic phase, leading to high film quality and homogeneous vertical distributions of A-site cations.

The on-demand formation of Lewis base molecules for fabricating efficient and stable formamidinium lead iodide (FAPbI.sub.3)-based perovskite solar cells (PSCs). Semicarbazide hydrochloride (SECl) is incorporated as an additive in the perovskite precursor, which deprotonates to form semicarbazide (SE) molecules when needed to stabilize the intermediate phase. SE molecules protonate again to form SECl salt when they must be removed rapidly to accelerate the transition from the intermediate phase to the photovoltaic phase, leading to high film quality and homogeneous vertical distributions of A-site cations.