ORGANIC-INORGANIC HYBRID PEROVSKITE, METHOD FOR PREPARING SAME, AND SOLAR CELL COMPRISING SAME

Abstract

The present invention relates to an organic/inorganic hybrid perovskite having a novel structure which can be used as an absorber of a solar cell, a method for preparing the same, and a solar cell comprising the same. The compound according to the present invention has a perovskite structure into which deuterium is introduced, thereby exhibiting high humidity and light stability, and thus can be useful as an absorber of a solar cell.

Claims

1. A compound represented by Chemical Formula 1 below:
(NH.sub.2CHNH.sub.2MX.sub.3).sub.x(AMX.sub.3).sub.(1-x)[Chemical Formula 1] in Chemical Formula 1, M is a divalent metal cation, X is the same or difference halogen, A is CD.sub.3-aH.sub.aN.sup.+D.sub.3-bH.sub.b, wherein a is an integer from 0 to 3, and b is an integer from 0 to 3, with the exception of the case where a is 3 and b is 3, M is a divalent metal cation, X are the same or different halogen, and x is a real number of greater than 0 and less than 1.

2. The compound according to claim 1, wherein M is Pb.sup.2+, Sn.sup.2+, Pd.sup.2+, Cu.sup.2+, Ge.sup.2+, Sr.sup.2+, Cd.sup.2+, Ca.sup.2+, Ni.sup.2+, Mn.sup.2+, Fe.sup.2+, Co.sup.2+, Sn.sup.2+, Yb.sup.2+, or Eu.sup.2+.

3. The compound according to claim 1, wherein each X is independently Cl.sup., Br.sup., or I.sup..

4. The compound according to claim 1, wherein A is CD.sub.3N.sup.+D.sub.3, CD.sub.3N.sup.+D.sub.2H, CD.sub.3N.sup.+DH.sub.2, CD.sub.3N.sup.+H.sub.3, CD.sub.2HN.sup.+D.sub.3, CD.sub.2HN.sup.+D.sub.2H, CD.sub.2HN.sup.+DH.sub.2, CD.sub.2HN.sup.+H.sub.3, CDH.sub.2N.sup.+D.sub.3, CDH.sub.2N.sup.+D.sub.2H, CDH.sub.2N.sup.+DH.sub.2, CDH.sub.2N.sup.+H.sub.3, CH.sub.3N.sup.+D.sub.3, CH.sub.3N.sup.+D.sub.2H, or CH.sub.3N.sup.+DH.sub.2.

5. The compound according to claim 1, wherein M is Pb.sup.2+, Sn.sup.2+, Pd.sup.2+, Cu.sup.2+, Ge.sup.2+, Sr.sup.2+, Cd.sup.2+, Ca.sup.2+, Ni.sup.2+, Mn.sup.2+, Fe.sup.2+, Co.sup.2+, Sn.sup.2+, Yb.sup.2+, or Eu.sup.2+.

6. The compound according to claim 1, wherein each X is independently Cl.sup., Br.sup., or I.sup..

7. The compound according to claim 1, wherein x is a real number of 0.6 or more and 0.8 or less.

8. The compound according to claim 1, wherein M and M are the same as each other.

9. The compound according to claim 1, wherein X and X all are the same.

10. The compound according to claim 1, wherein the compound represented by Chemical Formula 1 is represented by Chemical Formula 1-1 or 1-2:
(NH.sub.2CHNH.sub.2PbI.sub.3).sub.0.7(CD.sub.3ND.sub.2HPbX.sub.3).sub.0.3[Chemical Formula 1-1]
(NH.sub.2CHNH.sub.2PbI.sub.3).sub.0.7(CD.sub.3ND.sub.2PbX.sub.3).sub.0.3[Chemical Formula 1-2]

11. A solar cell comprising the compound of claim 1 as an absorber.

12. The solar e according to claim 11, wherein the solar cell has the following structure: a first electrode including a conductive transparent substrate; an electron transport layer formed on the first electrode; a light absorbing layer formed on the electron transport layer and including the compound represented by Chemical Formula 1; a hole transport layer formed on the light absorbing layer; and a second electrode formed on the hole transport layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] FIG. 1 shows the efficiency of the solar cells of the compounds prepared in Examples and Comparative Examples of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0063] Below, preferred examples will be described in order to better understand the present invention. However, these examples are provided for easier understanding of the invention only, and should not be construed as limiting the scope of the present invention thereto.

Preparation Example 1: Preparation of methyl ammonium iodide-d.SUB.5

[0064] A 2 L vacuum flask was injected with methyl amine-d.sub.5 gas. The flask was maintained at 78 C. (dry ice and acetone bath) for about 15 minutes until the gas was condensed to become liquid. 5 g of Methanol-d.sub.4 was injected into the flask with a syringe and stirred for 30 minutes, and then the temperature was raised to 0 C. Hydriodic acid (HI 57 wt %) (22.66 mL, 0.17 mol) was added and stirred for 1.5 hours. The solvent was removed using a rotary evaporator, washed with diethyl ether, and then filtered and vacuum-dried to obtain methyl ammonium iodide-d.sub.5 (10.98 g, 80.4%).

[0065] .sup.2H NMR (spinning rate=18 kHz) (600 MHz, ppm): 1.1(3, s), 5.2(2, s)

[0066] .sup.1H NMR (D.sub.2O(700 MHz), ppm): 4.28(1, s)

Preparation Example 2: Preparation of Methyl ammonium bromide-d.SUB.5

[0067] Methyl ammonium bromide-d.sub.5 was prepared in the same manner as in Preparation Example 1, except that hydrobromic acid (HBr 48 wt %) was used instead of hydriodic acid (HI 57 wt %).

[0068] .sup.2H NMR (spinning rate=18 kHz) (600 MHz, ppm): 1.2(3, s), 5.3(2, s)

[0069] .sup.1H NMR (D.sub.2O(700 MHz), ppm): 4.30(1, s)

Preparation Example 3: Preparation of Methyl ammonium chloride-d.SUB.5

[0070] Methyl ammonium chloride-d.sub.5 was prepared in the same manner as in Preparation Example 1, except that hydrochloric acid (HCl 37 wt %) was used instead of hydriodic acid (HI 57 wt %).

[0071] .sup.2H NMR (spinning rate=18 kHz) (600 MHz, ppm): 1.2(3, s), 5.4(2, s)

[0072] .sup.1H NMR (D.sub.2O(700 MHz), ppm): 4.31(1, s)

Preparation Example 4: Preparation of Methyl ammonium fluoride-d.SUB.5

[0073] Methyl ammonium fluoride-d.sub.5 was prepared in the same manner as in Preparation Example 1, except that hydrofluoric acid (HF 48 wt %) was used instead of hydriodic acid (HI 57 wt %).

[0074] .sup.2H NMR (spinning rate=18 kHz) (600 MHz, ppm): 1.2(3, s), 5.5(2, s)

[0075] .sup.1H NMR (D.sub.2O (700 MHz), ppm): 4.32(1, s)

Preparation Example 5: Preparation of Methyl ammonium iodide-d.SUB.6

[0076] Methyl ammonium iodide-d.sub.6 was prepared in the same manner as in Preparation Example 1, except that deuterium iodide (DI 57 wt %) was used instead of hydriodic acid (HI 57 wt %).

[0077] .sup.2H NMR (spinning rate=18 kHz) (600 MHz, ppm): 1.1(3, s), 5.2(3, s)

Preparation Example 6: Preparation of Methyl ammonium bromide-d.SUB.6

[0078] Methyl ammonium bromide-d.sub.6 was prepared in the same manner as in Preparation Example 2, except that deuterium bromide (DBr 47 wt %) was used instead of hydrobromic acid (HBr 48 wt %).

[0079] .sup.2H NMR (spinning rate=18 kHz) (600 MHz, ppm): 1.2(3, s), 5.3(3, s)

Preparation Example 7: Preparation of Methyl ammonium chloride-d.SUB.6

[0080] Methyl ammonium chloride-d.sub.6 was prepared in the same manner as in Preparation Example 3, except that deuterium chloride (DCI 35 wt %) was used instead of hydrochloric acid (HCl 37 wt %).

[0081] .sup.2H NMR (spinning rate=18 kHz) (600 MHz, ppm): 1.2(3, s), 5.4(3, s)

Preparation Example 8: Preparation of FAI (formamidinium iodide)

[0082] Formamidine acetate was placed in a 500 mL flask and cooled on an ice bath. After 15 minutes, hydriodic acid (HI) (2 eq) was dropped using a dropping funnel under an argon atmosphere. After stirring at 50 C. for 30 minutes, all remaining solvent was removed at 50 C. with a rotary evaporator. Precipitated FAI was added to diethyl ether, washed with stirring for 10 minutes, filtered, and the procedure was repeated one more time. The washed FAI was added to ethanol and dissolved with stirring at 50 C. Then, the solution was placed in a refrigerator and recrystallized for one day. After recrystallization, the product was filtered and dried in a vacuum oven at 50 C. for 12 hours to obtain a final product (4.21 g, 39%).

[0083] .sup.1H NMR (D.sub.2O(700 MHz), ppm): 7.2(5, s)

Preparation Example 9: Preparation of Methyl ammonium iodide

[0084] Methyl ammonium iodide (yield: 80.4%) was prepared in the same manner as in Preparation Example 8, except that Methyl amine solution (40 wt % in methanol) was used instead of formamidine acetate.

[0085] .sup.1H NMR (D.sub.2O(700 MHz), ppm): 8.52(3, s), 2.47(3, s)

Comparative Example 1: Preparation of (FAPbl.SUB.3.).SUB.0.7.(CH.SUB.3.NH.SUB.3.Pbl.SUB.3.).SUB.0.3

[0086] Formamidinium iodide prepared in Preparation Example 8 and lead iodide(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1, and methyl ammonium iodide prepared in Preparation Example 9 and lead iodide(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Each solution was mixed in a molar ratio of 7:3 and stirred at 70 C. for 2 hours to prepare 40 wt % of (FAPbl.sub.3).sub.0.7(CH.sub.3NH.sub.3Pbl.sub.3).sub.0.3 solution.

Example 1: Preparation of (FAPbl.SUB.3.).SUB.0.7.(CD.SUB.3.ND.SUB.2.HPbl.SUB.3.).SUB.0.3

[0087] Formamidinium iodide prepared in Preparation Example 8 and lead iodide(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1, and methyl ammonium iodide-d.sub.5 prepared in Preparation Example 1 and lead iodide(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Each solution was mixed in a molar ratio of 7:3 and stirred at 70 C. for 2 hours to prepare 40 wt % of (FAPbl.sub.3).sub.0.7(CD.sub.3ND.sub.2HPbl.sub.3).sub.0.3 solution.

Example 2: Preparation of (FAPbl.SUB.3.).SUB.0.7.(CD.SUB.3.ND.SUB.2.HPbBr.SUB.3.).SUB.0.3

[0088] Formamidinium iodide prepared in Preparation Example 8 and lead iodide(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1, and methyl ammonium bromide-d.sub.5 prepared in Preparation Example 2 and lead iodide(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Each solution was mixed in a molar ratio of 7:3 and stirred at 70 C. for 2 hours to prepare 40 wt % of (FAPbl.sub.3).sub.0.7(CD.sub.3ND.sub.2HPbBr.sub.3).sub.0.3.

Example 3: Preparation of (FAPbl.SUB.3.).SUB.0.7.(CD.SUB.3.ND.SUB.2.HPbCl.SUB.3.).SUB.0.3

[0089] Formamidinium iodide prepared in Preparation Example 8 and lead iodide(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1, and methyl ammonium chloride-d.sub.5 prepared in Preparation Example 3 and lead chloride(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Each solution was mixed in a molar ratio of 7:3 and stirred at 70 C. for 2 hours to prepare 40 wt % of (FAPbl.sub.3).sub.0.7(CD.sub.3ND.sub.2HPbCl.sub.3).sub.0.3 solution.

Example 4: Preparation of (FAPbl.SUB.3.).SUB.0.7.(CD.SUB.3.ND.SUB.2.HPbF.SUB.3.).SUB.0.3

[0090] Formamidinium iodide prepared in Preparation Example 8 and lead iodide (II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Methyl ammonium fluoride-d.sub.5 iodide prepared in Preparation Example 4 and lead fluoride(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Each solution was mixed in a molar ratio of 7:3 and stirred at 70 C. for 2 hours to prepare 40 wt % of (FAPbl.sub.3).sub.0.7(CD.sub.3ND.sub.2HPbF.sub.3).sub.0.3 solution.

Example 5: Preparation of (FAPbl.SUB.3.).SUB.0.7.(CD.SUB.3.ND.SUB.3.Pbl.SUB.3.).SUB.0.3

[0091] Formamidinium iodide prepared in Preparation Example 8 iodide and lead iodide (II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Methyl ammonium iodide-d.sub.6 prepared in Preparation Example 5 and lead iodide (II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Each solution was mixed in a molar ratio of 7:3 and stirred at 70 C. for 2 hours to prepare 40 wt % of (FAPbl.sub.3).sub.07(CD.sub.3ND.sub.3Pbl.sub.3).sub.0.3 solution.

Example 6: Preparation of (FAPbl.SUB.3.).SUB.0.7.(CD.SUB.3.ND.SUB.3.PbBr.SUB.3.).SUB.0.3

[0092] Formamidinium iodide prepared in Preparation Example 8 and lead iodide(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1, and methyl ammonium iodide-d.sub.6 prepared in Preparation Example 6 and lead bromide (II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Each solution was mixed in a molar ratio of 7:3 and stirred at 70 C. for 2 hours to prepare 40 wt % of (FAPbl.sub.3).sub.0.7(CD.sub.3ND.sub.3PbBr.sub.3).sub.0.3 solution.

Example 7: Preparation of (FAPbl.SUB.3.).SUB.0.7.(CD.SUB.3.ND.SUB.3.PbCl.SUB.3.).SUB.0.3

[0093] Formamidinium iodide prepared in Preparation Example 8 and lead iodide (II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Methyl ammonium iodide-d.sub.6 prepared in Preparation Example 6 and lead chloride(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Each solution was mixed in a molar ratio of 7:3 and stirred at 70 C. for 2 hours to prepare 40 wt % of (FAPbl.sub.3).sub.0.7(CD.sub.3ND.sub.3PbBr.sub.3).sub.0.3 solution.

Example 8: Preparation of (FAPbl.SUB.3.).SUB.0.7.(CD.SUB.3.ND.SUB.3.PbF.SUB.3.).SUB.0.3

[0094] Formamidinium iodide prepared in Preparation Example 8 and lead iodide(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Methyl ammonium iodide-d.sub.6 prepared in Preparation Example 6 and lead fluoride(II) were dissolved in 1-methyl-pyrrolidone in a molar ratio of 1:1. Each solution was mixed in a molar ratio of 7:3 and stirred at 70 C. for 2 hours to prepare 40 wt % of (FAPbl.sub.3).sub.0.7(CD.sub.3ND.sub.3PbF.sub.3).sub.0.3 solution.

Experimental Example

[0095] FTO glass (Pikington, TEC-7, 7 /sq) was washed with ethanol using ultrasonic waves for 40 minutes. FTO substrate was coated by a spin coating method using 0.1M titanium(IV) bis(ethylacetoacetato)diisopropoxide/1-butanol solution (Preparation of a first electrode). After heat treatment at 500 C. for 15 minutes, a solution prepared by diluting 1 g of TiO.sub.2 paste with 10 mL of ethanol was coated with TiO.sub.2 paste by a spin coating method, followed by heat treatment at 500 C. for 1 hour.

[0096] Each solution prepared in Examples 1 to 8 and Comparative Example was dropped onto an FTO glass coated with a TiO.sub.2 film (2.52.5 cm.sup.2), and coated by a spin coating method, to which toluene was added as a non-solvent in a drop wise manner 10 seconds before the end. The reaction product was heat-treated on a hotplate at 100 C. for 10 minutes. Subsequently, a hole transport layer was prepared by coating 60 mM of Spiro-OMeTAD/Li-TFSI/Tert-butylpyridine/chlorobenzene (Aldrich) by a spin coating method. The anode was etched with a width of 2.5 cm and a length of 0.5 cm and masked, and then Au was deposited to prepare an electrode (second electrode).

[0097] The efficiency of the solar cell was measured using the solar cell manufactured as described above, and the results are shown in Table 1 and FIG. 1 below. The humidity during measurement was maintained at 20%. Table 1 shows the measurement results at the time of the first measurement, and FIG. 1 shows the power generation efficiency measured with the lapse of time.

TABLE-US-00001 TABLE 1 Power Short-circuit Open-circuit Performance generation current density voltage index efficiency (mA/cm.sup.2) (V) (%) (%) Comparative 23.58 1.06 0.73 18.28 Example Example 1 24.57 1.03 0.74 18.92 Example 2 23.59 1.09 0.76 19.83

[0098] As shown in Table 1 and FIG. 1, at the time of the initial measurement, the solar cells of Examples had higher power generation efficiency than the solar cell of Comparative Example. Furthermore, it was confirmed that in Comparative Example, the power generation efficiency was rapidly lowered over time after the initial measurement, whereas in Examples, the power generation efficiency was maintained at a high numerical value for a long time.