Method of formulating perovskite solar cell materials

1. A method comprising the steps of:

preparing a bismuth halide precursor ink, wherein preparing a bismuth halide precursor ink comprises the steps of:

introducing a bismuth halide into a vessel;

introducing a first solvent to the vessel; and

contacting the bismuth halide with the first solvent to dissolve the bismuth halide to form the bismuth halide precursor ink;

depositing the bismuth halide precursor ink onto a substrate;

drying the bismuth halide precursor ink to form a thin film;

annealing the thin film; and

rinsing the thin film with a solvent comprising:

a second solvent;

a first salt selected from the group consisting of methylammonium halide, formamidinimum halide, guanidinium halide, 1,2,2-triaminovinylammonium halide, and 5-aminovaleric acid hydrohalide; and

a second salt selected from the group consisting of methylammonium halide, formamidinimum halide, guanidinium halide, 1,2,2-triaminovinylammonium halide, and 5-aminovaleric acid hydrohalide.

2. The method of claim 1 , wherein annealing the thin film occurs for between about 5 to about 30 minutes at a temperature between about 40° C. to about 60° C.

3. The method of claim 1 , wherein annealing the thin film occurs for about ten minutes at a temperature of about 50° C.

4. The method of claim 1 , wherein contacting the bismuth halide with the first solvent to dissolve the bismuth halide occurs between about 20° C. to about 150° C.

5. The method of claim 1 , wherein contacting the bismuth halide with the first solvent to dissolve the bismuth halide occurs at about 85° C.

6. The method of claim 1 , wherein depositing the bismuth halide precursor ink onto the substrate occurs by drop casting, spin casting, slot-die printing, screen printing, or ink-jet printing.

7. The method of claim 1 , wherein the first solvent is selected from the group consisting of dry dimethylformamide, dimethylsulfoxide (DMSO), methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, pyridine, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof.

8. The method of claim 1 , wherein the second solvent selected from the group consisting of dimethylformamide, isopropanol, methanol, ethanol, butanol, chloroform, chlorobenzene, dimethylsulfoxide, water, and combinations thereof.

9. The method of claim 1 , wherein the first salt is selected from the group consisting of methylammonium iodide, formamidinium iodide, guanidinium iodide, 1,2,2-triaminovinylammonium iodide, and 5-aminovaleric acid hydroiodide.

10. The method of claim 9 , wherein the first salt comprises formamidinium iodide and the second salt comprises guanidium iodide.

11. The method of claim 9 , wherein the first salt comprises methylammonium iodide and the second salt comprises guanidium iodide.

12. The method of claim 1 , wherein rinsing the thin film comprises at least partial submersion in the second solvent.

13. A perovskite material prepared by a process comprising the steps of:

preparing a bismuth halide precursor ink, wherein preparing a bismuth halide precursor ink comprises the steps of:

introducing a bismuth halide into a vessel;

introducing a first solvent to the vessel; and

contacting the bismuth halide with the first solvent to dissolve the bismuth halide to form the bismuth halide precursor ink;

depositing the bismuth halide precursor ink onto a substrate;

drying the bismuth halide precursor ink to form a thin film;

annealing the thin film; and

rinsing the thin film with a solvent comprising:

a second solvent;

a first salt selected from the group consisting of methylammonium halide, formamidinimum halide, guanidinium halide, 1,2,2-triaminovinylammonium halide, and 5-aminovaleric acid hydrohalide; and

a second salt selected from the group consisting of methylammonium halide, formamidinimum halide, guanidinium halide, 1,2,2-triaminovinylammonium halide, and 5-aminovaleric acid hydrohalide.

14. The perovskite material of claim 13 , wherein annealing the thin film occurs for between about 5 to about 30 minutes at a temperature between about 40° C. to about 60° C.

15. The perovskite material of claim 13 , wherein contacting the bismuth halide with the first solvent to dissolve the bismuth halide occurs between about 20° C. to about 150° C.

16. The perovskite material of claim 13 , wherein the first solvent is selected from the group consisting of dry dimethylformamide, dimethylsulfoxide (DMSO), methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, pyridine, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof.

17. The perovskite material of claim 13 , wherein the second solvent selected from the group consisting of dimethylformamide, isopropanol, methanol, ethanol, butanol, chloroform, chlorobenzene, dimethylsulfoxide, water, and combinations thereof.

18. The perovskite material of claim 13 , wherein the first salt is selected from the group consisting of methylammonium iodide, formamidinium iodide, guanidinium iodide, 1,2,2-triaminovinylammonium iodide, and 5-aminovaleric acid hydroiodide.

19. The perovskite material of claim 18 , wherein the first salt comprises formamidinium iodide and the second salt comprises guanidium iodide.

20. The perovskite material of claim 18 , wherein the first salt comprises methylammonium iodide and the second salt comprises guanidium iodide.