Pb-free perovskite materials for short wave IR devices
View Patent ↗The present disclosure is directed to methods of making Pb-free perovskites for short-wave IR (SWIR) devices and to various Pb-free perovskite materials disclosed herein. The perovskites disclosed herein have improved chemical stability and long-term stability, while the production methods disclosed herein have improved safety and lower cost.
1. A Pb-free perovskite material having a general formula A 3+ B + C + 2 X 6 wherein:
A 3+ is a trivalent metal cation,
B + is a first monovalent metal cation,
C + is a second monovalent metal cation,
X is a monovalent nonmetal anion,
the Pb-free perovskite material has been annealed to a surface of a substrate by an annealing process comprising an annealing time between about 10 and 30 minutes,
the surface of the substrate comprises glass, and
the Pb-free perovskite material has a wavelength of maximum absorbance from 1000 nm to 2800 nm.
2. The Pb-free perovskite material of claim 1 , wherein A 3+ a bismuth trivalent cation, an antimony trivalent cation, or an indium trivalent cation.
3. The Pb-free perovskite material of claim 1 , wherein B + is a silver monovalent cation, a copper monovalent cation, a gold monovalent cation, or a sodium monovalent cation.
4. The Pb-free perovskite material of claim 1 , wherein C + is a cesium monovalent cation.
5. The Pb-free perovskite material of claim 1 , wherein X is Br—, Cl— or I—.
6. The Pb-free perovskite material of claim 1 , further comprising a stabilizer.
7. The Pb-free perovskite material of claim 6 , wherein the stabilizer contains 1-(3-sulfopropyl) pyridinium hydroxide inner salt, dimethyl sulfoxide, or combinations thereof.
8. The Pb-free perovskite material of claim 6 , wherein the stabilizer is glass.
9. The Pb-free perovskite material of claim 1 , wherein the wavelength of maximum absorbance does not change at ambient temperature for longer than 8 days.
10. The Pb-free perovskite material of claim 1 , wherein the annealing time is about 10 minutes.
11. The Pb-free perovskite material of claim 1 , wherein the annealing process comprises an annealing temperature of between about 250 and 300° C.
12. A method of making the Pb-free perovskite material of claim 1 , comprising:
preparing a precursor solution in a solvent by:
dissolving a first compound, comprising: A 3+ , and X, in the solvent;
dissolving a second compound, comprising: B + , and X, in the solvent;
dissolving a third compound, comprising: C + , and X, in the solvent,
wherein the molar ratio of the first compound:second compound:third compound is about 1:1:2, in the solvent;
dispersing the precursor solution on the substrate; and
annealing the dispersed precursor solution on the substrate at an annealing temperature from 40-300° C., to form a Pb-free perovskite material.
13. The method of claim 12 , wherein the annealing is done in a vacuum.
14. The method of claim 12 , further comprising the substrate is heated to a temperature from 170-190° C. before dispersing the precursor solution on the substrate.
15. The method of claim 12 , further comprising adding a stabilizer to the precursor solution before dispersing the precursor solution on a substrate.
16. The method of claim 15 , wherein the stabilizer comprises 1-(3-sulfopropyl) pyridinium hydroxide inner salt, DMSO, or combinations thereof.
17. The method of claim 12 , wherein the substrate is a glass substrate and the glass substrate is operative to stabilize the Pb-free perovskite material.
18. The method of claim 12 , further comprising wherein the annealing temperature is selected from a temperature in the range from 40-300° C. and wherein the annealing temperature is operative to determine a wavelength of maximum SWIR absorbance of the Pb-free perovskite material.
19. The method of claim 12 , wherein X is Br—, Cl—, or I—.
20. The method of claim 12 , wherein the solvent is dimethylsulfoxide.
21. The method of claim 12 , wherein the dispersing the precursor solution on a substrate is done by spin coating the precursor solution on the substrate.
22. The method of claim 12 , wherein the first compound contains bismuth trivalent cation, antimony trivalent cation, indium trivalent cation, or combinations thereof.
23. The method of claim 12 , wherein the second compound contains silver monovalent cation, copper monovalent cation, gold monovalent cation, sodium monovalent cation, or combinations thereof.
24. The method of claim 12 , wherein the third compound contains cesium monovalent cation, an organic metal monovalent cation, an inorganic metal monovalent cation, or combinations thereof.