Processing of perovskite films using inks with complexing agents

A method, comprising:

• providing an ink comprising reactants, a complexing agent, and a solvent, wherein:
• the reactants comprise a first and a second cation, a first metal, and a first and a second anion, wherein the first and second cations are different from each other, and the first and second anions are different from each other;
• depositing the ink onto a substrate to form a wet film;
• drying the wet film to form a precursor layer;
• and
• annealing the precursor layer to form a perovskite film, wherein:
• the perovskite film comprises a mixed-cation mixed-halide perovskite material;
• the perovskite film comprises less than 5% by mass of the complexing agent;
• and
• the perovskite film is formed using a one-step process.

A method, comprising:

• providing an ink comprising reactants, a complexing agent, and a solvent, wherein:
• the reactants comprise a first and a second cation, a first metal, and a first and a second anion, wherein the first and second cations are different from each other, and the first and second anions are different from each other;
• the complexing agent comprises:
• a molar solubility greater than 0.05 to at least one of the reactants;
• a complex binding strength to the first metal greater than that of dimethylformamide (DMF) and less than that of dimethylsulfoxide (DMSO);
• and
• a boiling point less than 200° C.;
• depositing the ink onto a substrate to form a wet film;
• drying the wet film to form a precursor layer;
• and
• annealing the precursor layer to form a perovskite film, wherein the perovskite film comprises:
• a mixed-cation mixed-halide perovskite material;
• and
• less than 5% by mass of the complexing agent.