Perovskite solar cell

Abstract

An embodiment of the present invention provides a perovskite solar cell comprising: a lower electrode; a hole transport layer formed on the lower electrode; a perovskite layer formed on the hole transport layer; the passivation layer is formed on the perovskite layer; an electron transport layer formed on the passivation layer; and an upper electrode formed on the electron transport layer, in which the passivation layer contains a halide organic material.

Description

TECHNICAL FIELD

[0001] The present application relates to a perovskite solar cell. BACKGROUND

[0002] A perovskite solar cell is a solar cell device in which a perovskite structure material is used as a light absorbing layer. The perovskite solar cell has most of the characteristics of the next generation solar cell, such as high photoelectric conversion efficiency, low manufacturing cost, and the ability to perform low-temperature processes and low-cost solution processes, and thus is attracting attention as a next generation solar cell to replace silicon solar cells.

[0003] In the process of forming a thin film, the perovskite solar cell has various defects on the exposed surface. In the ABX3 structure, the organic compound corresponding to A and the halide corresponding to X are released from the ABX3 structure due to factors such as light, heat, pressure, electric field, and magnetic field, thereby forming defects such as vacancies and interstitials. In addition, in the existing method, the conduction band level of the perovskite light absorbing layer can be lower than that of the electron transport layer. In this case, an additional energy level adjustment layer must be inserted between the two layers to match the conduction band levels of the two layers. SUMMARY

[0004] PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] The present application can provide a perovskite solar cell including a passivation layer containing a halide organic compound.

[0006] TECHNICAL SOLUTION

[0007] In one aspect, the present application provides a perovskite solar cell including a lower electrode, a hole transport layer formed on the lower electrode, a perovskite layer formed on the hole transport layer, a passivation layer formed on the peroviskite layer, an electron transport layer formed on the passivation layer, and an upper electrode formed on the electron transport layer, wherein the passivation layer contains a compound of the following Chemical Formula 1:

[0008] [Chemical Formula 1]

[0009]

[0010] In the Chemical Formula 1, R 1 is hydrogen or C 1-10 alkyl, R 2 is F, Cl, Br, or I, and L is hydrogen or C 1-10 alkylene.

[0011] In one embodiment of the present application, the R 1 is hydrogen or C 1-5Alkyl, the R 2 The molecule is Br, and the L can be hydrogen or C. 1-5 Alkylene.

[0012] In one embodiment of the present invention, the concentration of the compound of chemical formula 1 in the passivation layer can be from 0.1 to 1 mM.

[0013] In one embodiment of the present invention, the upper electrode and the lower electrode may be transparent electrodes or metal electrodes, respectively.

[0014] In one embodiment of the present invention, the transparent electrode may include ITO, IZO, AZO or FTO, and the metal electrode may include Ag, Au, Al, Cu, SnPb, SnAgBi or SnAgCu.

[0015] In one embodiment of the present invention, the hole transport layer may include at least one selected from the group consisting of Spiro-OMeTAD, PEDOT:PSS, G-PEDOT, PANI:PSS, PANI:CSA, PDBT, P3HT, PCPDTBT, PCDTBT, PTAA, 2PACz, Me-4PACz, MoO3, V2O5, NiO, WO3, CuI, CuSCN, and combinations thereof.

[0016] In one embodiment of the present invention, the perovskite layer may include a perovskite material of the following chemical formula 2:

[0017] [Chemical Formula 2]

[0018] ABX3

[0019] In the chemical formula 2, A is an alkali metal or C. 1-25 The substituted or unsubstituted alkyl group, wherein when A is substituted, the substituent is amino, hydroxy, cyano, halogen, nitro, or methoxy; B comprises a metal cation selected from the group consisting of Pb, Sn, Ge, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, and combinations thereof; and X comprises a halide anion or a chalcogenide anion.

[0020] In one embodiment of the present invention, the electron transport layer may include at least one selected from the group consisting of BaSnO3, TiO2, ZrO, Al2O3, SnO2, ZnO, WO3, NbOH, Nb2O5, TiSrO3 and combinations thereof.

[0021] In one embodiment of the present invention, a lower solar cell may be further included, which is located below the lower electrode.

[0022] In one embodiment of the present invention, the lower solar cell may be a polycrystalline silicon solar cell, a crystalline silicon solar cell, a perovskite solar cell, a GaAs solar cell, a CdTe solar cell, a CIGS solar cell, a CZTS solar cell, an organic solar cell, a dye-sensitized solar cell, or a III-V compound solar cell.

[0023] In one embodiment of the present invention, a buffer layer may be further included, the buffer layer being disposed between the hole transport layer and the perovskite layer, between the electron transport layer and the passivation layer, or between both.

[0024] In one embodiment of the present invention, the buffer layer may include at least one of LiF, PEAI, PEABr, 4F-PEAI, octylammonium iodide, oleylamine, 2PACz, 4PACz, Me-4PACz, and MeO-2PACz.

[0025] In one embodiment of the present invention, the work function of the perovskite layer may be equal to or less than 5 eV.

[0026] In one embodiment of the present invention, the open-circuit voltage of the perovskite solar cell can be equal to or higher than 1.000V.

[0027] Another aspect of the present invention provides a method for manufacturing a perovskite solar cell, comprising the following steps: preparing a lower electrode; forming a hole transport layer on the lower electrode; forming a perovskite layer on the hole transport layer; forming a passivation layer on the perovskite layer; forming an electron transport layer on the passivation layer; and forming an upper electrode on the electron transport layer, wherein the passivation layer comprises a compound of the chemical formula 1.

[0028] Invention Effects

[0029] The perovskite solar cell according to the present invention controls surface defects in the perovskite solar cell by introducing a halide organic layer, thereby suppressing electron-hole recombination caused by defects. This improves the open-circuit voltage and stability of the perovskite solar cell. Furthermore, by reducing the work function of the perovskite to exhibit n-type characteristics, the conduction band energy level difference between the electron transport layer and the perovskite layer can be reduced, thereby improving the open-circuit voltage. Attached Figure Description

[0030] Figure 1 This is a schematic cross-sectional view of a perovskite solar cell according to an embodiment of the present invention.

[0031] Figure 2 This is a schematic cross-sectional view of a perovskite solar cell according to another embodiment of the present invention.

[0032] Figure 3 This is a flowchart illustrating a method for manufacturing a perovskite solar cell according to an embodiment of the present invention.

[0033] Figure 4 The X-ray photoelectron spectroscopy (XPS) analysis results of the perovskite layer and passivation layer according to an embodiment of the present invention are shown.

[0034] Explanation of reference numerals in the attached figures

[0035] 1, 1': Perovskite solar cell 10: Upper electrode

[0036] 20: Electron transport layer; 30: Passivation layer

[0037] 40: Perovskite layer; 50: Hole transport layer

[0038] 60: Lower electrode; 70: Lower solar cell Detailed Implementation

[0039] An embodiment of the present invention provides a perovskite solar cell, comprising: a lower electrode; a hole transport layer formed on the lower electrode; a perovskite layer formed on the hole transport layer; a passivation layer formed on the perovskite layer; an electron transport layer formed on the passivation layer; and an upper electrode formed on the electron transport layer, wherein the passivation layer comprises a compound of the following chemical formula 1:

[0040] [Chemical Formula 1]

[0041]

[0042] In the chemical formula 1, R 1 It is hydrogen or C 1-10 Alkyl, R 2 For F, Cl, Br, or I, and for L, for hydrogen or C 1-10 Alkylene.

[0043] Another embodiment of the present invention provides a method for manufacturing a perovskite solar cell, comprising the following steps: preparing a lower electrode; forming a hole transport layer on the lower electrode; forming a perovskite layer on the hole transport layer; forming a passivation layer on the perovskite layer; forming an electron transport layer on the passivation layer; and forming an upper electrode on the electron transport layer, wherein the passivation layer comprises a compound of chemical formula 1.

[0044] Implementation of the invention

[0045] The accompanying drawings illustrate one embodiment of the invention. However, the inventive concept can be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided to make this disclosure more thorough and complete, and to fully convey the scope of the inventive concept to those skilled in the art. The same reference numerals denote the same constituent elements.

[0046] The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the inventive concept. As used herein, the singular form is intended to include the plural form, which includes "at least one," unless the context clearly specifies otherwise. "At least one" should not be construed as limited to the singular. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items. The terms "comprising" and / or "including" as used in the summary of the invention mean the presence of features, regions, integers, steps, actions, constituent elements, and / or components, but do not exclude the presence or addition of one or more other features, regions, integers, steps, actions, constituent elements, components, and / or combinations thereof.

[0047] As used in this article, when referring to a component as being "on" or "on" another component, this includes not only cases where it is directly on another component, but also cases where other components are sandwiched between them.

[0048] Throughout the specification, when one part is described as "connected (linked, contacted, joined)" to another part, this includes not only the case of "direct connection" but also the case of "indirect connection" with another component sandwiched in between.

[0049] Unless otherwise defined, all techniques (including technical and scientific terms) used in this specification have the same meaning as commonly understood by those skilled in the art. Furthermore, it should be understood that terms defined in common dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and this disclosure, rather than an idealized or overly formal meaning.

[0050] Although specific embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that may not currently be anticipated or foreseen by the applicant or those skilled in the art are possible. Therefore, the appended claims, both applicable and amended, are intended to cover all such alternatives, modifications, variations, improvements, and substantial equivalents.

[0051] In this invention, unless otherwise stated, the terms "alkyl" and "alkylene" can be straight-chain or branched, and the number of carbon atoms is not particularly limited, but can be from 1 to 25. According to one embodiment, the alkyl group has 1 to 10 carbon atoms. According to another embodiment, the alkyl group has 1 to 5 carbon atoms. Specific examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethylpropyl, 1,1-dimethylpropyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, etc.

[0052] In the following embodiments, the terms "first," "second," etc., are used to distinguish one constituent element from other constituent elements, rather than having a limiting meaning.

[0053] In the following embodiments, unless the context clearly describes otherwise, singular expressions include plural expressions.

[0054] In the accompanying drawings, the dimensions of the constituent elements may be enlarged or reduced for ease of description. For example, the dimensions and thicknesses of each component shown in the drawings are arbitrarily illustrated for ease of description, and therefore the invention is not necessarily limited to what is shown.

[0055] In the following embodiments, the x-axis, y-axis, and z-axis are not limited to three axes in an orthogonal coordinate system, and can be interpreted to include them in a general sense. For example, the x-axis, y-axis, and z-axis can be orthogonal to each other, but can also refer to different directions that are not orthogonal to each other.

[0056] Where certain embodiments can be implemented differently, a particular process sequence may be performed differently than the described sequence. For example, two processes described consecutively may actually be performed simultaneously, or may be performed in the reverse order of the described sequence.

[0057] A perovskite solar cell according to an embodiment of the present invention may include a lower electrode, a hole transport layer, a perovskite layer, a passivation layer, an electron transport layer, and an upper electrode.

[0058] Figure 1 This is a schematic cross-sectional view of a perovskite solar cell according to an embodiment of the present invention.

[0059] according to Figure 1The perovskite solar cell 1 may include a lower electrode 60, a hole transport layer 50, a perovskite layer 40, a passivation layer 30, an electron transport layer 20, and an upper electrode 10.

[0060] The passivation layer 30 may contain a compound of the following chemical formula 1.

[0061] [Chemical Formula 1]

[0062]

[0063] In the chemical formula 1,

[0064] R 1 It is hydrogen or C 1-10 alkyl,

[0065] R 2 For F, Cl, Br or I, and

[0066] L can be hydrogen or C. 1-10 Alkylene.

[0067] More specifically, the R 1 It is hydrogen or C 1-5 alkyl,

[0068] The R 2 For Br, and

[0069] The L can be hydrogen or C. 1-5 Alkylene.

[0070] The compound of chemical formula 1 may be 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene, but is not limited thereto.

[0071] The concentration of the compound of formula 1 in the passivation layer 30 may be 0.1 to 1 mM; 0.1 to 0.8 mM; 0.1 to 0.6 mM; 0.1 to 0.4 mM; 0.2 to 1 mM; 0.2 to 0.8 mM; 0.2 to 0.6 mM; or 0.2 to 0.4 mM.

[0072] The surface defects of perovskite solar cells can be controlled by including a compound of Formula 1 on the passivation layer 30, thereby improving the electrical performance of the device. Furthermore, the open-circuit voltage can be improved by adjusting the energy levels on the surface of the perovskite solar cell. In addition, the stability of the perovskite solar cell can be improved.

[0073] The upper electrode 10 and the lower electrode 60 can be either transparent electrodes or metal electrodes. Preferably, at least one of the upper electrode 10 and the lower electrode 60 can be a transparent electrode.

[0074] Transparent electrodes can be used to facilitate charge collection in the horizontal direction. The upper electrode 10 can be a transparent electrode, but a metal electrode pattern can be formed and laminated on the upper part of the transparent electrode. When the lower electrode 60 is connected to the lower solar cell, the lower electrode 60 is preferably a transparent electrode.

[0075] The transparent electrode may include ITO, IZO, AZO or FTO, and the metal electrode may include Ag, Au, Al, Cu, SnPb, SnAgBi or SnAgCu, but is not limited thereto.

[0076] The perovskite layer 40 may contain a perovskite material of the following chemical formula 2.

[0077] [Chemical Formula 2]

[0078] ABX3

[0079] In the chemical formula 2,

[0080] A is an alkali metal or C. 1-25 Substituted or unsubstituted alkyl groups,

[0081] When A is substituted, the substituent is amino, hydroxyl, cyano, halogen, nitro, or methoxy.

[0082] The B comprises a metal cation selected from the group consisting of Pb, Sn, Ge, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, and combinations thereof, and

[0083] X may include halide anions or chalcogenide anions.

[0084] More specifically, A may include formamidinium ions, methylamine ions, cesium, rubidium, potassium, sodium, lithium, guanidine ions, butylammonium ions, ethylammonium ions, or phenylethylamine ions; B may include lead, tin, germanium, cadmium, zinc, or magnesium, etc.; and X material may include iodides, bromides, chlorides, fluorides, thiocyanates, cyanates, selenocyanates, formate, or acetate, etc.

[0085] The hole transport layer 50 is used to transport holes formed in the perovskite layer 40 to the lower electrode 60 while blocking the movement of electrons. It may include at least one selected from the group consisting of Spiro-OMeTAD, PEDOT:PSS, G-PEDOT, PANI:PSS, PANI:CSA, PDBT, P3HT, PCPDTBT, PCDTBT, PTAA, 2PACz, Me-4PACz, MoO3, V2O5, NiO, WO3, CuI, CuSCN, and combinations thereof.

[0086] The electron transport layer 20 is used to transport electrons formed in the perovskite layer 40 to the upper electrode 10 while blocking the movement of holes. It may include at least one selected from the group consisting of BaSnO3, TiO2, ZrO, Al2O3, SnO2, ZnO, WO3, NbOH, Nb2O5, TiSrO3 and combinations thereof.

[0087] On the other hand, at least one of the holes transport layer 50 and the perovskite layer 40, and at least one of the electron transport layer 20 and the passivation layer 30, may further include a buffer layer.

[0088] The buffer layer is used to prevent interface defects and improve transmission capability, and may include at least one of LiF, PEAI, PEABr, 4F-PEAI, octylammonium iodide, oleylamine, 2PACz, 4PACz, Me-4PACz, and MeO-2PACz.

[0089] According to another embodiment of the present invention, the perovskite solar cell may further include a lower solar cell.

[0090] Figure 2 This is a schematic cross-sectional view of a perovskite solar cell that further includes a lower solar cell according to an embodiment of the present invention.

[0091] according to Figure 2 The perovskite solar cell 1' may further include a lower solar cell 70 located below the lower electrode 60.

[0092] The lower solar cell 70 may be a polycrystalline silicon solar cell, a crystalline silicon solar cell, a perovskite solar cell, a GaAs solar cell, a CdTe solar cell, a CIGS solar cell, a CZTS solar cell, an organic solar cell, a dye-sensitized solar cell, or a III-V compound solar cell, but is not limited thereto.

[0093] When a lower solar cell 70 is included below the lower electrode 60, the lower electrode 60 can serve as a recombination layer, inducing the recombination of electrons and holes generated in the lower solar cell 70 and the upper perovskite solar cell. Therefore, in this case, the lower electrode 60 is preferably a transparent electrode.

[0094] The hole transport layer 50, perovskite layer 40, passivation layer 30, electron transport layer 20, and upper electrode 10 are the same as those in the previous embodiments, or can be modified and applied as needed, so more detailed descriptions will be omitted.

[0095] Figure 3 This is a flowchart illustrating a method for manufacturing a perovskite solar cell according to an embodiment of the present invention.

[0096] The present invention provides a method for manufacturing a perovskite solar cell, which includes the following steps: preparing a lower electrode S100, forming a hole transport layer S200, forming a perovskite layer S300, forming a passivation layer S400, forming an electron transport layer S500, and forming an upper electrode S600.

[0097] Another embodiment of the present invention may further include the step of forming a buffer layer in at least one of the following steps: between forming the hole transport layer S200 and forming the perovskite layer S300; or between forming the passivation layer S400 and forming the electron transport layer S500.

[0098] The lower electrode, hole transport layer, perovskite layer, passivation layer, electron transport layer, upper electrode, and buffer layer are the same as those in the previous embodiments, or can be modified and applied as needed, so more detailed descriptions will be omitted.

[0099] The invention will be described in more detail below with reference to experimental examples.

[0100] However, the experimental examples described later are merely specific examples of one aspect of the present invention, and the present invention is not limited thereto.

[0101] <Experimental Example 1> Ultraviolet Photoelectron Spectroscopy (UPS)

[0102] According to the present invention, ultraviolet photoelectron spectroscopy was performed on a perovskite layer containing a passivation layer (example) and a perovskite layer without a passivation layer (control group). The experimental results are shown in Table 1 below.

[0103]

[0104] As can be seen from Table 1, compared with the control group, the work function of the perovskite layer containing the passivation layer is reduced, and its energy level is tuned to a morphology closer to the N-type.

[0105] <Experimental Example 2> X-ray photoelectron spectroscopy (XPS)

[0106] X-ray photoelectron spectroscopy was performed on the control group of Experimental Example 1 and Examples 1 to 3. The experimental results are as follows: Figure 4 As shown.

[0107] from Figure 4 It can be seen that, compared with the control group, Examples 1 to 3, which contain a passivation layer, correspond to Pb 0The peak value decreases. Due to the lower work function of the passivation layer, the conduction band of the adjacent electron transport layer is relatively reduced, which is expected to promote the extraction of electrons generated in the light absorption layer.

[0108] <Experimental Example 3> Evaluation of Open-Circuit Voltage and Efficiency of Solar Cells

[0109] The open-circuit voltage, short-circuit current, fill factor, and efficiency of the control group of Experiment 1 and the perovskite solar cells including Examples 1 to 3 were evaluated. A total of 5 evaluations were conducted, and the experimental results are shown in Table 2 below.

[0110]

[0111] As can be seen from Table 2, the open-circuit voltage of all solar cells (including the examples) increased compared to the control group. In particular, the solar cells including Example 1 exhibited improved peak and average efficiencies due to the increased open-circuit voltage.

[0112] The description of this invention is for illustrative purposes only, and those skilled in the art should understand that the invention can be readily modified into other specific forms without changing the inventive concept or essential features. Therefore, the embodiments described above should be understood as exemplary in all respects, not restrictive. For example, each component described as a single type can be implemented separately, and similarly, components described as distributed can be implemented in combination.

[0113] The scope of this invention is embodied in the claims described later, and should be interpreted as including the meaning and scope of the claims, as well as all variations or modifications derived from the equivalent concept, within the scope of this invention.

Claims

1. A perovskite solar cell comprising: a lower electrode; a hole transport layer formed on the lower electrode; a perovskite layer formed on the hole transport layer; a passivation layer formed on the perovskite layer; an electron transport layer formed on the passivation layer; and an upper electrode formed on the electron transport layer, wherein the passivation layer comprises a compound of Chemical Formula 1: [Chemical Formula 1] in the Chemical Formula 1, R 1 is hydrogen or C 1-10 alkyl, R 2 is F, Cl, Br or I, and L is hydrogen or C 1-10 alkylene. 2.The perovskite solar cell of claim 1, wherein R is hydrogen or C 1 alkyl, and 1-5 alkyl, and The R 2 For Br, and The L is hydrogen or C 1-5 alkylene. 3.The perovskite solar cell of claim 1, wherein a concentration of the compound of Chemical Formula 1 in the passivation layer is 0.1 to 1 mM. 4.The perovskite solar cell of claim 1, wherein the upper and lower electrodes are transparent electrodes or metal electrodes, respectively. 5.The perovskite solar cell of claim 4, wherein the transparent electrode comprises ITO, IZO, AZO, or FTO, the metal electrode comprises Ag, Au, Al, Cu, SnPb, SnAgBi, or SnAgCu. 6.The perovskite solar cell of claim 1, wherein the hole transport layer comprises at least one selected from the group consisting of Spiro-OMeTAD, PEDOT:PSS, G-PEDOT, PANI:PSS, PANI:CSA, PDBT, P3HT, PCPDTBT, PCDTBT, PTAA, 2PACz, Me-4PACz, MoO3, V2O5, NiO, WO3, CuI, CuSCN, and combinations thereof. 7.The perovskite solar cell of claim 1, wherein the perovskite layer comprises a perovskite material of Chemical Formula 2: [Chemical Formula 2] ABX3 in the Chemical Formula 2, The A is an alkali metal or C 1-25 substituted or unsubstituted alkyl, when the A is substituted, the substituent is an amino group, a hydroxyl group, a cyano group, a halogen group, a nitro group, or a methoxy group, the B comprises a metal cation selected from the group consisting of Pb, Sn, Ge, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, and combinations thereof, and the X comprises a halide anion or a chalcogenide anion. 8.The perovskite solar cell of claim 1, wherein the electron transport layer comprises at least one selected from the group consisting of BaSnO3, TiO2, ZrO, Al2O3, SnO2, ZnO, WO3, NbOH, Nb2O5, TiSrO3, and combinations thereof. 9.The perovskite solar cell of claim 1, further comprising: a lower solar cell located below the lower electrode. 10.The perovskite solar cell of claim 9, wherein the lower solar cell is a poly crystalline silicon solar cell, a crystalline silicon solar cell, a perovskite solar cell, a GaAs solar cell, a CdTe solar cell, a CIGS solar cell, a CZTS solar cell, an organic solar cell, a dye-sensitized solar cell, or a III-V compound solar cell.

11. The perovskite solar cell according to claim 1 or 9, further comprising a buffer layer between the hole transport layer and the perovskite layer, between the electron transport layer and the passivation layer, or both.

12. The perovskite solar cell according to claim 11, wherein the buffer layer comprises at least one of LiF, PEAI, PEABr, 4F-PEAI, octylammonium iodide, oleylamine, 2PACz, 4PACz, Me-4PACz, and MeO-2PACz.

13. The perovskite solar cell according to claim 1, wherein the work function of the perovskite layer is equal to or lower than 5 eV.

14. The perovskite solar cell according to claim 1, wherein the open circuit voltage of the perovskite solar cell is equal to or higher than 1.000 V.

15. A method for manufacturing a perovskite solar cell, comprising the steps of: preparing a lower electrode; forming a hole transport layer on the lower electrode; forming a perovskite layer on the hole transport layer; forming a passivation layer on the perovskite layer; forming an electron transport layer on the passivation layer; and forming an upper electrode on the electron transport layer, wherein the passivation layer comprises the compound according to claim 1. ​

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