Methods for producing single crystal mixed halide perovskites
View Patent ↗An aspect of the present invention is a method that includes contacting a metal halide and a first alkylammonium halide in a solvent to form a solution and maintaining the solution at a first temperature, resulting in the formation of at least one alkylammonium halide perovskite crystal, where the metal halide includes a first halogen and a metal, the first alkylammonium halide includes the first halogen, the at least one alkylammonium halide perovskite crystal includes the metal and the first halogen, and the first temperature is above about 21° C.
1. A method comprising:
contacting a lead halide, a first alkylammonium halide (AAH), and a second AAH in a solvent to form a solution; and
maintaining the solution at a first temperature above 21° C., resulting in the formation of an alkylammonium dihalide perovskite crystal, wherein:
the lead halide comprises a first halogen,
the first AAH comprises the first halogen,
the second AAH comprises a second halogen that is different from the first halogen,
the solution has a first molar amount of the first AAH, a second molar amount of the second AAH, and a third molar amount of the lead halide,
the first molar amount and the second molar amount are present at a first molar ratio of the first molar amount divided by second molar amount defined by (1−y)/y with 0<y≦0.5,
the first molar amount, the second molar amount, and the third molar amount are present at a second molar ratio defined by the sum of the first molar amount and the second molar amount divided by the third molar amount where the second molar ratio is between 0.8 and 1.2 inclusively, and
the alkylammonium dihalide perovskite crystal comprises lead, the first halogen, and the second halogen.
2. The method of claim 1 , wherein the lead halide is selected from the group consisting of PbBr 2 , PbI 2 , and PbCl 2 .
3. The method of claim 1 , wherein the first alkylammonium halide comprises at least one of CH 3 NH 3 Br, CH 3 NH 3 I, CH 3 NH 3 Cl, HC(NH 2 ) 2 I, HC(NH 2 ) 2 Br, or HC(NH 2 ) 2 Cl.
4. The method of claim 1 , wherein the second alkylammonium halide comprises at least one of CH 3 NH 3 Cl, CH 3 NH 3 Br, CH 3 NH 3 I, HC(NH 2 ) 2 I, HC(NH 2 ) 2 Br, or HC(NH 2 ) 2 Cl.
5. The method of claim 1 , wherein the solvent comprises a polar solvent.
6. The method of claim 5 , wherein the polar solvent comprises at least one of dimethysulfoxide, dimethylformamide, γ-butyrolactone, or N-methyl-2-pyrrolidone.
7. The method of claim 1 , wherein the first temperature is between 40° C. and 100° C.
8. The method of claim 1 , wherein the maintaining is for a first period of time between 30 seconds and 100 hours.
9. The method of claim 1 , further comprising, prior to the maintaining, heating the solution from a starting temperature to the first temperature.
10. The method of claim 9 , wherein the starting temperature is between 0° C. and 30° C.
11. The method of claim 9 , wherein the heating is achieved in a second period of time between 1 minute and 10 minutes.
12. The method of claim 1 , wherein the lead halide is PbBr 2 , the first alkylammonium halide is CH 3 NH 3 Br, the second alkylammonium halide is CH 3 NH 3 Cl, the solvent is dimethylformamide, the first temperature is about 50° C., the alkylammonium dihalide perovskite crystal is CH 3 NH 3 Pb(Br 1-x Cl x ), and 0<x≦0.25.