Gas-induced perovskite formation

1. A method of forming a perovskite film, comprising:

inducing a chemical reaction between a metal halide compound and methylamine (CH 3 NH 2 ) gas by exposing the metal halide compound to a heated methylamine (CH 3 NH 2 ) solution.

2. The method of claim 1 , wherein the inducing of the chemical reaction between the metal halide compound and the methylamine (CH 3 NH 2 ) gas comprises:

forming a metal halide film comprising the metal halide compound on a substrate; and

exposing the metal halide film to the methylamine (CH 3 NH 2 ) gas for inducing the chemical reaction between the metal halide compound and the methylamine (CH 3 NH 2 ) gas to form a first perovskite film.

3. A solar cell comprising a perovskite film as an active layer, the perovskite film fabricated by using the method of claim 1 , wherein

power conversion efficiency of the solar cell is greater than 7%.

4. The method of claim 2 , wherein the exposing of the metal halide film to the methylamine (CH 3 NH 2 ) gas comprises:

attaching the substrate with a spin-coated metal halide compound on an internal bottom surface of a first container;

placing a second container containing the methylamine (CH 3 NH 2 ) solution on a heated plate to generate the methylamine (CH 3 NH 2 ) gas; and

placing the first container including the substrate with the spin-coated metal halide compound attached on the internal bottom surface thereof to cover the second container containing the methylamine (CH 3 NH 2 ) solution placed on the heated plate, by orienting a substrate surface having the spin-coated metal halide compound to face an opening of the second container.

5. The method of claim 2 , further comprising:

exposing the first perovskite film to hydriodic acid (HI) gas to form a second perovskite film.

6. The method of claim 2 , further comprising:

exposing the first perovskite film to hydriodic acid (HI) gas and methylamine (CH 3 NH 2 ) gas sequentially for one or more cycles to form a third perovskite film.

7. The method of claim 2 , further comprising:

exposing the first perovskite film to hydriodic acid (HI) gas and methylamine (CH 3 NH 2 ) gas simultaneously to form a fourth perovskite film.

8. The method of claim 2 , wherein

a size of the substrate is 10×10 cm 2 or larger.

9. The method of claim 2 , further comprising: exposing the first perovskite film to hydriodic acid (HI) gas, wherein the exposing the first perovskite film to the hydriodic acid (HI) gas comprises:

placing the first perovskite film on a heated plate;

covering the first perovskite film on the heated plate with a third container; and

placing a fourth container containing a HI solution inside the third container and in the proximity of the first perovskite film.

10. A perovskite film fabricated by using the method of claim 2 , the perovskite film comprising:

stoichiometric CH 3 NH 3 PbI 3 perovskite, wherein the perovskite has a mirror-like semi-transparent appearance with a RMS surface roughness of about 2 nm and grain sizes in the range of 40-70 nm.

11. The method of claim 5 , wherein

the metal halide compound is PbI 2 , and

the exposing the first perovskite film to hydriodic acid (HI) gas is configured to induce a conversion of PbO x+y H 2y included in the first perovskite film to PbI 2 .

12. The method of claim 6 , wherein

the metal halide compound is PbI 2 ,

the exposing the first perovskite film to hydriodic acid (HI) gas and methylamine (CH 3 NH 2 ) gas sequentially is configured to induce a conversion of PbO x+y H 2y included in the first perovskite film to PbI 2 , and sequentially to induce a chemical reaction between PbI 2 and the methylamine (CH 3 NH 2 ) gas.

13. The method of claim 7 , wherein

the metal halide compound is PbI 2 ,

the exposing the first perovskite film to hydriodic acid (HI) gas and methylamine (CH 3 NH 2 ) gas simultaneously is configured to induce a conversion of PbO x+y H 2y included in the first perovskite film to PbI 2 , and simultaneously to induce a chemical reaction between PbI 2 and the methylamine (CH 3 NH 2 ) gas.

14. A perovskite film fabricated by using a method comprising: forming a PbI 2 film on a substrate; exposing the PbI 2 film to methylamine (CH 3 NH 2 ) gas for inducing a chemical reaction between PbI 2 and methylamine (CH 3 NH 2 ) gas to form a first perovskite film; and exposing the first perovskite film to hydriodic acid (HI) gas and methylamine (CH 3 NH 2 ) gas sequentially for one or more cycles to form the perovskite film, the perovskite film comprising:

a reduced amount of PbO x+y H 2y compared to the first perovskite, based on a conversion of PbO x+y H 2y included in the first perovskite film to PbI 2 , and sequentially a chemical reaction between PbI 2 and the methylamine (CH 3 NH 2 ) gas, wherein the perovskite film has a RMS surface roughness of about 14 nm and grain sizes of about 400 nm.

15. A perovskite film fabricated by using a method comprising: forming a PbI 2 film on a substrate; exposing the PbI 2 film to methylamine (CH 3 NH 2 ) gas for inducing a chemical reaction between PbI 2 and methylamine (CH 3 NH 2 ) gas to form a first perovskite film; and exposing the first perovskite film to hydriodic acid (HI) gas and methylamine (CH 3 NH 2 ) gas simultaneously to form the perovskite film, the perovskite film comprising:

a reduced amount of PbO x+y H 2y compared to the first perovskite, based on a conversion of PbO x+y H 2y included in the first perovskite film to PbI 2 , and simultaneously a chemical reaction between PbI 2 and the methylamine (CH 3 NH 2 ) gas, wherein the perovskite film has a RMS surface roughness of about 6 nm and grain sizes of about 200 nm.