Surfactant additive for solution coating large area high efficiency perovskite solar cells and other devices

1. A method of forming a photoactive device, the method comprising steps of:

providing a perovskite-surfactant solution,

said perovskite-surfactant solution comprising a perovskite ink and a zwitterionic surfactant; wherein the perovskite ink comprises at least one solvent; and wherein a concentration of said surfactant in said perovskite-surfactant solution is selected from the range of 0.01 to 1 mM; and

coating said perovskite-surfactant solution onto a receiving surface of a substrate in a coating step thereby forming a layer of said photoactive device;

wherein said layer comprises a perovskite material;

wherein the perovskite material crystallizes during the coating step;

wherein during the step of coating the surfactant forms a first self-assembled layer at a first interface, the first interface being an interface of the substrate and the perovskite-surfactant solution, with hydrophobic groups of the surfactant aligned to the receiving surface of the substrate and hydrophilic groups of the surfactant aligned to the perovskite-surfactant solution at the first interface;

wherein during the step of coating the surfactant further forms a second self-assembled layer at a second interface, the second interface being an interface of the perovskite-surfactant solution and air, with hydrophobic groups of the surfactant pointing to the air and hydrophilic groups of the surfactant aligned to the perovskite-surfactant solution at the second interface;

wherein the step of coating is performed using a blade coating process; and wherein an active area of said photoactive device is at least 1 cm 2 .

2. The method of claim 1 , wherein said coating is performed at a coating speed of at least 20 mm/s.

3. The method of claim 1 , wherein said substrate is heated to a temperature of at least 100° C. during said step of coating.

4. The method of claim 1 , further comprising combining said surfactant and said perovskite ink to form said perovskite-surfactant solution.

5. The method of claim 1 , wherein the perovskite material comprises at least one of methylammonium lead halide, formamidinium lead halide, cesium lead halide, methylammonium tin halide, formamidinium tin halide, and cesium tin halide.

6. The method of claim 1 , wherein the at least one solvent comprises at least one of water, methanol, 1-propanol (PrOH), isopropyl alcohol, 1-Pentanol, hydrogen iodide aqueous solution, dimethylethanolamine, acetic acid, xylene, ethylene glycol, diethyl ether, acetonitrile, Sulfolane, Dimethylformamide (DMF), Diethylformamide, methyl phenyl sulfoxide, diphenyl sulfoxide, diethyl sulfite, methylsulfonylmethane, tetramethylene sulfane, ethylene sulfite, nitrous acid, nitromethane, thiosulfuric acid, dimethyl sulfate, hydrophosphorous acid, sulfuric acid, phosphoric acid, Formamide, Dimethylacetamide (DMAc), N-Methylformamide, N-Methyl-2-pyrrolidone (NMP), 1,3-Dimethyl-2-imidazolidinone, N-Vinylacetamide, N,N′-Dimethylpropyleneurea (DMPU), 2-dimethylaminoethanol, Ethyl lactate, N-Vinylpyrrolidone, Dimethyl sulfoxide (DMSO), diethyl sulfoxide, tetrahydrothiophene oxide, N-Formylmorpholine, N-Methylformamide, 2-Pyrrolidone, Tetramethylurea, N-Vinylacetamide, N-Vinylpyrrolidone, Dimethyl sulfite, Diethyl sulfite, Methyl methanesulfonate, Dimethyl sulfate, 1,3-Dimethyl-2-imidazolidinone, gamma-Butyrolactone (GBL), Dioxane, Dioxolane, Propylene carbonate (PC), 1,2-dimethoxyethane, methyl ethyl ketone, 2-methylpyrazine, 2-Methoxyethanol, 2-Methoxyethanol acetate, 2-Ethoxyethanol, 2-Ethoxyethanol acetate, 1-Methoxy-2-propanol, 1-methoxy-2-propanol acetate, 2-Butoxyethanol, 2-Butoxyethanol acetate, 2-Propyloxyethanol, 2-Propyloxyethanol acetate, Ethyl 3-ethoxypropionate, ethylene glycol monopropyl ether, amine, and methylamine.

7. The method of claim 1 , wherein said active area is at least 15 cm 2 .

8. The method of claim 1 , wherein said photoactive device is a photovoltaic cell.

9. The method of claim 8 , wherein said photovoltaic cell is characterized by a photovoltaic efficiency of at least 15%.

10. The method of claim 1 , wherein the perovskite material is characterized by formula having a halide anion.

11. The method of claim 1 , wherein the perovskite material crystallizes during evaporation of the solvent during the step of coating.

12. The method of claim 1 , wherein the perovskite ink comprises a perovskite precursor that forms the perovskite material during coating of the perovskite-surfactant solution.

13. The method of claim 12 , wherein the perovskite precursor crystallizes into the perovskite layer as the solvent evaporates.

14. The method of claim 1 , wherein crystallized particles and/or crystallized islands of the perovskite material form in the coated perovskite-surfactant solution after the solution is coated onto the receiving surface of the substrate.

15. The method of claim 1 , wherein the layer of the photoactive device comprises the surfactant and wherein the surfactant passivates charge traps in the perovskite material.

16. The method of claim 1 , wherein the receiving surface comprises a hydrophobic surface.

17. The method of claim 1 , wherein the surfactant self-assembles forming a hydrophobic layer on a surface of the perovskite material.

18. A method of forming a photoactive device, the method comprising steps of:

providing a perovskite-surfactant solution,

said perovskite-surfactant solution comprising a perovskite ink and a zwitterionic surfactant; wherein the perovskite ink comprises at least one solvent; wherein a concentration of said surfactant in said perovskite-surfactant solution is selected from the range of 0.01 to 1 mM; and

coating said perovskite-surfactant solution onto a receiving surface of a substrate in a coating step thereby forming a layer of said photoactive device; wherein:

said layer comprises a perovskite material;

the perovskite material crystallizes during the coating step;

during the step of coating the surfactant forms a first self-assembled layer at a first interface, the first interface being an interface of the substrate and the perovskite-surfactant solution, with hydrophobic groups of the surfactant aligned to the receiving surface of the substrate and hydrophilic groups of the surfactant aligned to the perovskite-surfactant solution at the first interface;

during the step of coating the surfactant further forms a second self-assembled layer at a second interface, the second interface being an interface of the perovskite-surfactant solution and air, with hydrophobic groups of the surfactant pointing to the air and hydrophilic groups of the surfactant aligned to the perovskite-surfactant solution at the second interface;

the step of coating is performed using a blade coating process; and

said coating is performed at a coating speed of at least 10 mm/s.

19. The method of claim 18 , wherein an active area of said photoactive device is at least 1 cm 2 .

20. The method of claim 19 , wherein said active area is at least 15 cm 2 .

21. The method of claim 18 , wherein said photoactive device is a photovoltaic cell.

22. The method of claim 21 , wherein said photovoltaic cell is characterized by a photovoltaic efficiency of at least 15% and an active area of at least 1 cm2.