Organic-inorganic hybrid perovskites

Abstract

The application relates to organic-inorganic hybrid perovskites of formula (I): [(A).sub.1?2.48p?b(B).sub.3.48p+b].sub.(1+2p?y)/1+p)(Pb).sub.1?p?m(M).sub.m(X.sup.1).sub.3?y?q(X.sup.2).sub.q(I), and perovskite photovoltaic cells comprising the same.

Claims

1. An organic-inorganic hybrid perovskite of formula (I) below:
[(A).sub.1?2.48p?b(B).sub.3.48p+b].sub.(1+2p?y)/(1+p)(Pb).sub.1?p?m(M).sub.m(X.sup.1).sub.3?y?q(X.sup.2).sub.q(I) in which: A represents a cation chosen from Cs, Rb and a monovalent organic cation comprising an ammonium or carboxamidamidium group, B represents a monovalent organic cation of formula (II) below:
R.sup.1(CH.sub.2).sub.2R.sup.2(II) in which: R.sup.2 represents an ammonium or carboxamidamidium group, z represents 1, 2 or 3, and R.sup.1 represents H, OH, SH, CN or a halogen, with the proviso that B is other than A, X.sup.1 and X.sup.2 represent a halide, with the proviso that X.sup.1 and X.sup.2 are different from each other, p is a number from 0.05 to 0.23, b is a number greater than or equal to ?0.30 and less than or equal to 0.30, with the proviso that b is greater than ?3.48p and is less than (1?2.48p), y represents a number greater than 0 and less than or equal to p, q represents a number greater than or equal to 0 and less than or equal to (3?y), M represents a divalent metal cation, and m represents a number greater than or equal to 0 and less than or equal to (1?p).

2. The perovskite as claimed in claim 1, in which X.sup.1 represents an iodide and q represents 0.

3. The perovskite as claimed in claim 1, in which m represents 0.

4. The perovskite as claimed in claim 1, in which: the divalent metal cation is chosen from Pb, Sn, Cu, Cd and Mn, and/or the halide is chosen from an iodide, a chloride and a bromide, and/or the monovalent organic cation A is chosen from Cs, Rb, methylammonium and formamidinium, and/or y is equal to p, and/or b is a number greater than or equal to ?0.20 and less than or equal to 0.20, and/or m represents 0, and/or q represents 0.

5. The perovskite as claimed in claim 4, in which b is a number greater than or equal to ?0.10 and less than or equal to 0.10.

6. The perovskite as claimed in claim 4, in which b is a number greater than or equal to ?0.07 and less than or equal to 0.07.

7. The perovskite as claimed in claim 1, in which the monovalent organic cation B of formula (II) is HO(CH.sub.2).sub.2NH.sub.3.sup.+.

8. The perovskite as claimed in claim 1, of formula (VII) below:
[(A).sub.1?2.48p?b(HO(CH.sub.2).sub.2NH.sub.3.sup.+).sub.3.48p+b].sub.(1+2p?y)/(1+p)(Pb).sub.1?p(I).sub.3?y(VII) in which A, p, b and y are as defined in claim 1.

9. The perovskite as claimed in claim 8, in which A represents CH.sub.3NH.sub.3.sup.+ and/or y=p.

10. The perovskite as claimed in any one of the preceding claims, of formula (90), (92), (89), (93) or (88) below:
(CH.sub.3NH.sub.3).sub.0.8138(HO(CH.sub.2).sub.2NH.sub.3).sub.0.2848[Pb.sub.0.9014I.sub.2.9014](90),
(CH.sub.3NH.sub.3).sub.0.6744(HO(CH.sub.2).sub.2NH.sub.3).sub.0.4586[Pb.sub.0.8670I.sub.2.8670](92),
(CH.sub.3NH.sub.3).sub.0.5821(HO(CH.sub.2).sub.2NH.sub.3).sub.0.5763[Pb.sub.0.8416I.sub.2.8416](89),
(CH.sub.3NH.sub.3).sub.0.5383(HO(CH.sub.2).sub.2NH.sub.3).sub.0.6405[Pb.sub.0.8212I.sub.2.8212](93), or
(CH.sub.3NH.sub.3).sub.0.4730(HO(CH.sub.2).sub.2NH.sub.3).sub.0.7331[Pb.sub.07940I.sub.2.7940](88).

11. The perovskite as claimed in claim 1, in which the monovalent organic cation B of formula (II) is HS(CH.sub.2).sub.2NH.sub.3.sup.+.

12. The perovskite as claimed in claim 1 of formula (VIII) below:
[(A).sub.1?2.48p?b(HS(CH.sub.2).sub.2NH.sub.3.sup.+).sub.3.48p+b].sub.(1+2p?y)/(1+p)(Pb).sub.1?p(I).sub.3?y(VIII) in which A, p, b and y are as defined above.

13. The perovskite as claimed in claim 12, in which A represents FA and/or y=p.

14. The perovskite as claimed in claim 1, of formula (T1) below:
(HC(NH.sub.2).sub.2).sub.0.9177(HS(CH.sub.2).sub.2NH.sub.3).sub.0.1193[Pb.sub.0.9630I.sub.2.9630](T1).

15. The perovskite as claimed in claim 1, in the form of crystals, the crystalline system of which is of tetragonal symmetry.

16. The perovskite as claimed in claim 1, in the form of a thin layer at least partly covering the surface of a substrate.

17. A perovskite solar cell, at least one of the layers of which contains the perovskite as claimed in claim 1.

18. The perovskite as claimed in claim 1, having a three-dimensional structure.

19. The perovskite as claimed in claim 1, in which the monovalent organic cation B of formula (II) is chosen from CH.sub.3CH.sub.2NH.sub.3.sup.+, CH.sub.3C(NH.sub.2).sub.2.sup.+, HO(CH.sub.2).sub.2NH.sub.3.sup.+ and HS(CH.sub.2).sub.2NH.sub.3.sup.+.

Description

EXAMPLE 1: PREPARATION OF PEROVSKITES IN THE FORM OF CRYSTALS/CRYSTALLINE POWDERS

(1) In a first stage, a precursor solution close to saturation was prepared by dissolving ethanolamine, methylammonium iodide and PbI.sub.2 in 57% hydriodic acid solution (Aldrich compounds). The ethanolamine/methylammonium iodide/PbI.sub.2 molar proportions were 1/2/3, 1.5/2/3, 2/2/3, 2.5/2/3 and 3/2/3, for perovskites 90, 92, 89, 93 and 88, respectively.

(2) In a second stage, this precursor solution was added to ethyl acetate, leading to immediate precipitation of the perovskite. The powder obtained was filtered, washed with ethyl acetate and then dried in an oven for 15 to 20 minutes at 80? C.

(3) The crystalline powder obtained was analyzed by nuclear magnetic resonance (NMR) and X-ray (XR). Perovskite 88NMR (DMSO-de). Description: 1 signal at 2.39 ppm with an integration of 3H, associated with the methyl of the methylammonium ligand 1 signal at 2.87 ppm with an integration of 3.09H, associated with one CH.sub.2 of the ethanolammonium ligand 1 signal at 3.58 ppm with an integration of 3.15H, associated with the second CH.sub.2 of the ethanolammonium ligand 1 broad and weak signal at 5.13 ppm with an integration of 1.55H, associated with the HO of the ethanolammonium ligand 1 very broad signal at 7.67 ppm with an integration of 7.71 ppm, associated with the ammonium functions of the two ligands Perovskite 93NMR (DMSO-de). Description: 1 signal at 2.39 ppm with an integration of 3H, associated with the methyl of the methylammonium ligand 1 signal at 2.87 ppm with an integration of 2.35H, associated with one CH.sub.2 of the ethanolammonium ligand 1 signal at 3.58 ppm with an integration of 2.41H, associated with the second CH.sub.2 of the ethanolammonium ligand 1 broad and weak signal at 5.13 ppm with an integration of 1.19H, associated with the HO of the ethanolammonium ligand 1 very broad signal at 7.61 ppm with an integration of 6.49 ppm, associated with the ammonium functions of the two ligands Perovskite 89NMR (DMSO-de). Description: 1 signal at 2.39 ppm with an integration of 3H, associated with the methyl of the methylammonium ligand 1 signal at 2.87 ppm with an integration of 1.98H, associated with one CH.sub.2 of the ethanolammonium ligand 1 signal at 3.58 ppm with an integration of 1.99H, associated with the second CH.sub.2 of the ethanolammonium ligand 1 broad and weak signal at 5.14 ppm with an integration of 0.99H, associated with the HO of the ethanolammonium ligand 1 very broad signal at 7.60 ppm with an integration of 5.90 ppm, associated with the ammonium functions of the two ligands Perovskite 92NMR (DMSO-de). Description: 1 signal at 2.38 ppm with an integration of 3H, associated with the methyl of the methylammonium ligand 1 signal at 2.87 ppm with an integration of 1.38H, associated with one CH.sub.2 of the ethanolammonium ligand 1 signal at 3.57 ppm with an integration of 1.34H, associated with the second CH.sub.2 of the ethanolammonium ligand 1 broad and weak signal at 5.11 ppm with an integration of 0.68H, associated with the HO of the ethanolammonium ligand 1 very broad signal at 7.60 ppm with an integration of 5.27 ppm, associated with the ammonium functions of the two ligands Perovskite 90NMR (DMSO-de). Description: 1 signal at 2.39 ppm with an integration of 3H, associated with the methyl of the methylammonium ligand 1 signal at 2.88 ppm with an integration of 0.69H, associated with one CH.sub.2 of the ethanolammonium ligand 1 signal at 3.58 ppm with an integration of 0.71H, associated with the second CH.sub.2 of the ethanolammonium ligand 1 broad and weak signal at 5.12 ppm with an integration of 0.35H, associated with the HO of the ethanolammonium ligand 2 broad overlapping signals at 7.50 and 7.68 ppm, with a total integration of 4.12 ppm, associated with the ammonium functions of the two ligands Powder XR study (Bruker D8 Avance diffractometer, copper anticathode, Vantec detector)
Positions 2? in ? of the diffraction lines of the compounds in the angular range 5-32?
Perovskite 88: 6.235; 8.772; 12.412; 13.895; 18.745; 19.690; 22.379; 24.125; 25.669; 27.820; 28.768; 29.418; 31.241
Perovskite 93: 6.254; 8.810; 12.421; 13.905; 17.674; 18.745; 19.773; 22.494; 24.194; 24.981; 25.746; 27.896; 28.768; 29.380; 31.275
Perovskite 89: 8.896; 12.543; 14.012; 18.783; 19.820; 22.571; 24.285; 25.784; 28.011; 28.883; 29.533; 31.412
Perovskite 92: 14.092; 19.938; 24.388; 26.014; 28.125; 31.527
Perovskite 90: 13.980; 19.820; 24.297; 25.325; 28.125; 31.534

(4) The perovskites prepared all had a crystalline system of tetragonal symmetry.

(5) For perovskite 88, the lattice parameters are as follows:

(6) a=b=14.184 ?,

(7) c=6.292 ?

(8) ?=?=?=90?

(9) V=1266 ?.sup.3

EXAMPLE 2: PREPARATION OF PEROVSKITES IN THE FORM OF A THIN LAYER AND OF A PHOTOVOLTAIC DEVICE

(10) The photovoltaic device made consists of a glass support covered with a layer of fluorine-doped tin oxide (FTO) (TEC? (7)), onto which has been deposited by spraying a first electron transport layer (ETL) of compact TiO.sub.2, followed by deposition of a second layer of porous TiO.sub.2 by spin coating. The perovskite active layer according to the invention was deposited onto the porous TiO.sub.2 by spin coating (solvent: dimethylformamide, 1 molar solution), followed by annealing at 100? C. for 1 hour, and the spiro-OMeTAD hole transport material (HTM) layer was then deposited, also by spin coating. To finish, the silver electrode was deposited by evaporation.

(11) Under conditions not yet optimized, but identical for all the perovskites tested (namely MAPI, perovskite 90, perovskite 92 and perovskite 89), the photovoltaic yield results (PCE) are as follows (the announced value is a mean over 5 to 6 measurements):

(12) TABLE-US-00001 MAPI Perovskite (comparative) 90 92 89 PCE (series 1) 3.35% 3.74% 2.14% 1.88% PCE (series 2) 2.97% 4.02% 2.44% 2.07%

EXAMPLE 3: PREPARATION OF PEROVSKITE T1 IN THE FORM OF A CRYSTALLINE POWDER (NO CRYSTALS)

(13) In a first stage, a precursor solution close to saturation was prepared by dissolving cysteamine, formamidinium iodide and PbI.sub.2 in 57% hydriodic acid solution (Aldrich compounds). The cysteamine/formamidinium iodide/PbI.sub.2 molar proportions were 2.13/3/3.

(14) In a second stage, this precursor solution was added to ethyl acetate, leading to immediate precipitation of the perovskite. The powder obtained was filtered, washed with ethyl acetate and then dried in an oven for 15 to 20 minutes at 60? C.

(15) The crystalline powder obtained was analyzed by nuclear magnetic resonance (NMR) and X-ray (XR). Perovskite T1NMR (DMSO-de). Description: 1 signal at 2.69 ppm with an integration of 0.14H, associated with the hydrogen of the HS function of the thioethylammonium ligand. 1 signal at 2.96 ppm with an integration of 0.24H, associated with one CH.sub.2 of the thioethylammonium ligand. 1 signal at 3.14 ppm with an integration of 0.24H, associated with the second CH.sub.2 of the thioethylammonium ligand. 1 signal at 7.86 ppm with an integration of 1.38H, associated with the HC-hydrogen of the formamidinium ligand with an integration contribution of 1.00H+ associated with the NH.sub.3.sup.+ of the thioethylammonium ligand with an integration contribution of 0.38H. 1 signal at 8.66 ppm with an integration of 2.00H, associated with one NH.sub.2 of the formamidinium ligand. 1 signal at 9.00 ppm with an integration of 2.00H, associated with the second NH.sub.2 of the formamidinium ligand. Powder XR study (Bruker D8 Avance diffractometer, copper anticathode, point scintillation detector)
Positions 2? in ? of the diffraction lines of the compounds in the angular range 5-32? Perovskite T1: 13.949; 19.749; 24.249; 28.069; 31.449; 34.479; 40.089; 42.629; 49.749; 51.819; 58.139

EXAMPLE 4: PREPARATION OF PEROVSKITE T1 IN THIN LAYER FORM

(16) The thin layer was prepared by spin coating under ambient conditions. In a first stage, the solution containing the precursors was prepared by dissolving thioethylammonium iodide/formamidinium iodide/PbI.sub.2 in dimethylformamide (DMF), and adhering to stoichiometric proportions of 0.5/3/3. The PbI.sub.2 concentration was set at 1.2 mol/L. In a second stage, 60 ?L of this solution are deposited onto a 1.5*2 cm.sup.2 glass/FTO support (tec7, Pilkington), on the FTO side. The spin-coating program then imposed is 10 seconds at 1000 rpm (acceleration of 200 rpm/second), and then 20 seconds at 6000 rpm (acceleration of 3000 rpm/second). During this program (more precisely at 15 seconds), 300 ?L of ethyl acetate or 150 ?L of chlorobenzene are added directly to the rotating film. On conclusion of the spin coating, the thin-layer film undergoes a heat treatment on a hotplate at 100? C. for 30 minutes.

(17) Thin Layer Stability

(18) A comparison was made of the stability of perovskite T1 and of the known perovskite ?-FAPbI.sub.3 (FA.sup.+=formamidinium, HC(NH.sub.2).sub.2.sup.+) under laboratory conditions (air, light, 25? C., relative humidity of about 80%).

(19) After preparing the films by spin coating, they were left on a bench and X-ray diffraction analyses were performed regularly. The initial X-ray diffraction analysis shows that the thin films prepared correspond to the expected phases (positions 2? in ? of the diffraction lines of the compounds in the angular range 5-32?: Perovskite T1, 13.949, 19.749, 24.249, 28.069, 31.449; ?-FAPbI.sub.3, 13.969, 19.767, 24.218, 28.113, 31.510). After 25 hours, the first signs of appearance of the non-perovskite phase ?-FAPI appeared for the sample ?-FAPbI.sub.3 (line at position 2? 11.8?), signifying start of degradation.

(20) After 100 hours, whereas the sample of ?-FAPbI.sub.3 is completely transformed into ?-FAPI, there is no sign of degradation for the sample T1 (X-ray diffractogram identical to the initial one).