Dimethylammonium-containing perovskite devices

1. A perovskite comprising:

a tilt angle not equal to 180 degrees; and

DMA x Cs 1-x-y FA y BX 3 , wherein:

DMA is dimethylammonium,

FA is formamidinium,

B comprises a cation,

X comprises an anion,

0≤x≤0.8,

0.40≤y≤0.90,

the tilt angle is the angle at the anion (X) between two neighboring cations (B), and

the perovskite has a film density (ρ) of less than 4.37 g/cm 3 .

2. The perovskite of claim 1 , wherein X comprises at least one of chlorine, bromine, or iodine.

3. The perovskite of claim 2 , comprising DMA x Cs 1-x-y FA y PbI 3-v-z Br z Cl v , wherein 0.05≤x≤0.50, 0.29≤y≤0.70, 0≤v≤0.45, and 0≤z≤1.5.

4. The perovskite of claim 3 , comprising at least one of DMA 0.10 FA 0.60 CS 0.30 PbI 2.4 Br 0.6 , DMA 0.10 FA 0.60 CS 0.30 PbI 2.4 Br 0.6 Cl 0.06 , DMA 0.5 Cs 0.50 PbI 3 , DMA 0.5 Cs 0.50 PbI 2.4 Br 0.6 , DMA 0.1 FA 0.58 Cs 0.32 PbI 3 , DMA 0.1 FA 0.58 Cs 0.32 PbI 2.4 Br 0.6 , DMA 0.2 FA 0.435 Cs 0.365 PbI 3 , DMA 0.2 FA 0.435 Cs 0.365 PbI 2.4 Br 0.6 , DMA 0.3 FA 0.29 Cs 0.41 PbI 3 , DMA 0.3 FA 0.29 Cs 0.41 PbI 2.4 Br 0.6 , DMA 0.4 FA 0.145 Cs 0.455 PbI 3 , DMA 0.4 FA 0.145 Cs 0.455 PbI 2.4 Br 0.6 , DMA 0.4 FA 0.145 Cs 0.455 PbI 2.85 Br 0.15 , DMA 0.3 FA 0.29 Cs 0.41 PbI 2.6 Br 0.3 , DMA 0.2 FA 0.435 Cs 0.365 PbI 2.76 Br 0.24 , DMA 0.3 FA 0.29 Cs 0.41 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.15 FA 0.53 Cs 0.32 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.2 FA 0.44 Cs 0.36 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.25 FA 0.38 Cs 0.37 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.3 FA 0.30 Cs 0.40 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.15 FA 0.64 Cs 0.21 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.2 FA 0.60 Cs 0.2 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.25 FA 0.56 Cs 0.19 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.3 FA 0.52 Cs 0.18 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.2 FA 0.4 Cs 0.4 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.2 FA 0.48 Cs 0.32 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.25 FA 0.5 Cs 0.25 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.25 FA 0.45 Cs 0.3 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.2 FA 0.4 Cs 0.4 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.12 FA 0.65 Cs 0.23 PbI 2.55 Br 0.45 Cl 0.06 , DMA 0.1 FA 0.6 Cs 0.3 PbI 1.5 Br 1.5 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.85 Cl 0.15 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.94 Cl 0.06 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.9 Cl 0.1 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.55 Br 0.3 Cl 0.15 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.55 Br 0.3 Cl 0.15 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.55 Br 0.3 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.4 Br 0.3 Cl 0.3 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.55 Br 0.3 Cl 0.15 , DMA 0.1 FA 0.6 Cs 0.3 PbI 3 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.4 Br 0.45 Cl 0.15 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.55 Br 0.45 , DMA 0.1 FA 0.6 Cs 0.3 PbI 2.4 Br 0.15 Cl 0.45 , DMA 0.05 FA 0.7 Cs 0.25 PbI 2.4 Br 0.6 Cl 0.06 , DMA 0.05 FA 0.63 Cs 0.32 PbI 2.4 Br 0.6 Cl 0.06 , or DMA 0.2 FA 0.53 Cs 0.27 PbI 2.4 Br 0.6 Cl 0.06 .

5. The perovskite of claim 2 , comprising DMA x Cs 1-x-y FA y PbI 3-v Cl v , wherein 0<v<3.

6. The perovskite of claim 2 , comprising DMA x Cs 1-x-y FA y PbI 3-z Br z , wherein 0<z<3.

7. The perovskite of claim 2 , comprising DMA x Cs 1-x-y FA y PbI 3-v-z Br z Cl v , wherein 0<v<3, and 0<z<3.

8. The perovskite of claim 1 , wherein B comprises at least one of lead or tin.

9. The perovskite of claim 8 , comprising DMA x Cs 1-x-y FA y PbX 3 .

10. The perovskite of claim 1 , further comprising a unit cell volume greater than 480 Å 3 .

11. The perovskite of claim 10 , wherein the unit cell volume is between greater than 480 Å 3 and 485 Å 3 , inclusively.

12. The perovskite of claim 1 , further comprising a bandgap between 1.65 eV and 1.9 eV, inclusively.

13. The perovskite of claim 12 , wherein the bandgap is between 1.70 eV and 1.85 eV, inclusively.

14. The perovskite of claim 1 , wherein 4.1 g/cm 3 ≤ρ≤4.37 g/cm 3 .

15. The perovskite of claim 1 , further comprising at least one of guanidinium or acetamidinium.

16. The perovskite of claim 1 , wherein the tilt angle is between 153 degrees and less than 180 degrees, inclusively.