Solar cell assembly and perovskite solar cell comprising same

Abstract

The present invention relates to a solar cell assembly and a perovskite solar cell comprising same, specifically to a solar cell assembly and a perovskite solar cell comprising same in which, by comprising a compound having a specific structure in a buffer layer, the parasitic absorption problem consequent to the formation of a thick electron transport layer due to H2O, which is a reactant in the formation of an inorganic SnO2 buffer layer, can be resolved, and power conversion efficiency and safety can be improved.

Description

Assembly for a solar cell and a perovskite solar cell including the same

[0001] The present invention claims the benefit of the filing date of Korean Patent Application No. 10-2024-0154604 filed with the Korean Intellectual Property Office on November 4, 2024, and the entire contents thereof are incorporated into the present invention.

[0002] The present invention relates to an assembly for a solar cell and a perovskite solar cell comprising the same. Specifically, by including a compound having a specific structure in the buffer layer, the invention solves the problem of parasitic absorption caused by the formation of a thick electron transport layer due to H2O, a reactant, in the formation of an inorganic SnO2 buffer layer, and improves power conversion efficiency and safety. The invention relates to an assembly for a solar cell and a perovskite solar cell comprising the same.

[0003] With the launch of the new climate regime through the Paris Agreement, the Korean government aims to reduce greenhouse gas emissions by 37% compared to the 2030 Business As Usual (BAU) forecast of 850 million tons. Consequently, solar cell technology is expected to generate economic value based on the Paris Agreement and the national strategy for green growth. The solar power market has continued to experience remarkable growth over the past few years due to factors such as the severity of climate change, increasing concern over environmental pollution, and rising energy demand. Silicon solar cells, which currently account for a large share of the market, possess high photovoltaic conversion efficiency but have drawbacks, including a relatively low light absorption coefficient, expensive wafer costs, complex manufacturing processes, and the need for high-temperature heat treatment. To address these issues, thin-film solar cells are garnering attention for their high light absorption coefficients, which allow them to absorb and utilize sufficient light with only a small amount of material.

[0004] Perovskite solar cells have the advantage of being able to be used as single-junction opaque solar cells, as well as as semi-transparent (BIPV) or top cells in tandem, by having the band gap (Eg) of the perovskite light-absorbing layer tunability.

[0005] To be used as part of a semi-transparent (BIPV) or tandem solar cell, the metal back electrode must be changed to a transparent electrode structure. Although a sputtering process is performed to form such a transparent electrode, there is a problem where the electron transport layer is damaged by the shock caused by sputtering. To prevent this, a buffer layer was formed using SnO2 via the Atomic Layer Deposition (ALD) method; however, forming a buffer layer with SnO2 complicates the process and increases manufacturing costs due to the need for equipment and a separate layer, and there is a fundamental problem of SnO2 growth on the electron transport layer, so an organic buffer layer was added for interface control.

[0006] However, the above organic buffer layer is structured to be added separately between the inorganic buffer layer and the electron transport layer, which makes the structure more complex than before, reduces permeability, and consequently causes a problem of reduced current density.

[0007] The technical problem to be solved by the present invention is to provide a solar cell assembly and a perovskite solar cell comprising the same, wherein the material of the buffer layer used in conventional solar cells is changed from an inorganic material to an organic material, and the organic material is used as a compound having a specific structure, thereby having band alignment properties that facilitate electron extraction, possessing high conductivity, maintaining high transmittance, and capable of reducing impact on the electron transport layer during the sputtering process of forming electrodes.

[0008] However, the problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below.

[0009] One embodiment of the present invention provides an assembly for a solar cell comprising: an electron transport layer; and a buffer layer provided on the electron transport layer and containing the following chemical formula 1.

[0010] [Chemical Formula 1]

[0011]

[0012] Each of the above R1, R2, R5, and R6 is a substituted or unsubstituted methylene group or a substituted or unsubstituted straight-chain or branched-chain alkylene group having 2 to 10 carbon atoms, each of the above R3, R4, R7, and R8 is a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group or a substituted or unsubstituted straight-chain or branched-chain alkyl group having 3 to 10 carbon atoms, and n is an integer from 1 to 10.

[0013] According to one embodiment of the present invention, the molecular weight of the formula 1 may be 400 g / mol or more and 800 g / mol or less.

[0014] According to one embodiment of the present invention, the formula 1 may be the following formula 2 or formula 3.

[0015] [Chemical Formula 2]

[0016]

[0017] [Chemical Formula 3]

[0018]

[0019] According to one embodiment of the present invention, the electron transport layer may comprise a compound having 30 to 80 carbon atoms.

[0020] One embodiment of the present invention provides a perovskite solar cell comprising the above-described solar cell assembly, wherein a first transparent electrode layer; the buffer layer; the electron transport layer; a perovskite-based light absorption layer; a hole transport layer; and a second transparent electrode layer are sequentially provided.

[0021] According to one embodiment of the present invention, each of the first transparent electrode layer and the second transparent electrode layer may comprise a material selected from the group consisting of instrinsic-ZnO (intrinsic zinc oxide, i-ZnO), indium tin oxide (ITO), indium zinc oxide (IZO), zinc tin oxide (ZTO), aluminum-doped zinc oxide (Al-doped ZnO: AZO), boron-doped zinc oxide (B-doped ZnO: BZO), fluorine-doped tin oxide (F-doped SnO: FTO), and combinations thereof.

[0022] According to one embodiment of the present invention, the perovskite-based light absorption layer may comprise an organic-inorganic complex halide perovskite-based compound of the following chemical formula 4.

[0023] [Chemical Formula 4]

[0024] ABX3

[0025] The above A is one selected from the group consisting of CH3NH3, HC(NH2)2, Cs, Rb, and combinations thereof, the above B is one selected from the group consisting of Pb, Sn, and combinations thereof, and the above X is one selected from the group consisting of Cl, Br, I, and combinations thereof.

[0026] According to one embodiment of the present invention, in the above formula 4, A may be represented by the following formula 5, B may be represented by the following formula 6, and X3 may be represented by the following formula 7.

[0027] [Chemical Formula 5]

[0028] [CH3NH3] 1-a-b-c [HC(NH2)2] a Cs b Rb c

[0029] [Chemical Formula 6]

[0030] Pb 1-p Sn p

[0031] [Chemical Formula 7]

[0032] Cl 3-l-m B l I m

[0033] The above a is 0≤a≤1, the above b is 0≤b≤1, the above c is 0≤c≤1, the above p is 0≤a≤1, the above l is 0≤l≤3, and the above m is 0≤m≤3.

[0034] According to one embodiment of the present invention, the hole transport layer is NiOx(0 <x≤3), Me-4PACZ([4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid), MeO-2PACz([2-(3,6-Dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic Acid), MEO-4PACZ([4-(3,6-Dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid), 2PACz([2-(9H-Carbazol-9-yl)ethyl]phosphonic Acid), Br2-EPT, 폴리-[비스(4-페닐)(2,4,6-트리메틸페닐)아민](PTAA), 폴리아닐린, 폴리피롤, 폴리-3,4-에틸렌다이옥시싸이오펜-폴리스타이렌설포네이트(PEDOT:PSS), 스피로-미오타디(Spiro-MeOTAD), 폴리아닐린-캄포설폰산(PANI-CSA) 및 이들의 조합으로 이루어진 군으로부터 선택된 것을 포함하는 것일 수 있다.

[0035] An assembly for a solar cell according to one embodiment of the present invention can prevent damage to the electron transport layer, improve transmittance, easily form a buffer layer, and improve conductivity.

[0036] A perovskite solar cell according to one embodiment of the present invention can improve power conversion efficiency by achieving high conductivity and transparency, improve stability, and reduce sensitivity to changes in the thickness of the buffer layer.

[0037] FIG. 1 is a schematic diagram of an assembly for a solar cell according to one embodiment of the present invention.

[0038] FIG. 2 is a schematic diagram of a perovskite solar cell according to one embodiment of the present invention.

[0039] Figure 3 is a graph showing the short-circuit current according to the open-circuit voltage of Example 1, Comparative Example 1, and Comparative Example 2.

[0040] Figure 4 is a graph showing the short-circuit current according to the open-circuit voltage of Example 2, Comparative Example 3, and Comparative Example 4.

[0041] Figure 5 is a graph showing the short-circuit current according to the open-circuit voltage after 24 hours, 72 hours, and 1536 hours of Example 2 under dark conditions.

[0042] Figure 6 is a graph showing the short-circuit current according to the open-circuit voltage after 0 hours, 24 hours, and 144 hours have elapsed under the dark conditions of Comparative Example 3.

[0043] Figure 7 is a graph showing the power conversion efficiency over time under dark conditions of Example 2 and Comparative Example 3.

[0044] Figure 8 is a graph showing the power conversion efficiency according to the buffer layer solution concentration of Example 2 and Comparative Example 4.

[0045] In this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0046] In this specification, "A and / or B" means "A and B, or A or B".

[0047] In the present specification, when a component is said to be located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components.

[0048] In the present specification, "sequentially provided" may be stacked in order, and may not exclude other layers being provided between the stacked layers.

[0049] The drawings attached to this specification illustrate preferred embodiments of the invention and explain the principles of the invention together with the description of the invention, but the scope of the invention is not limited thereto. Meanwhile, the shapes, sizes, scales, or proportions of elements in the drawings included in this specification may be exaggerated to emphasize clearer explanations.

[0050] The present invention will be described in more detail below.

[0051] One embodiment of the present invention provides a solar cell assembly (1) comprising: an electron transport layer (100); and a buffer layer (200) provided on the electron transport layer (100) and containing the following chemical formula 1.

[0052] [Chemical Formula 1]

[0053]

[0054] Each of the above R1, R2, R5, and R6 is a substituted or unsubstituted methylene group or a substituted or unsubstituted straight-chain or branched-chain alkylene group having 2 to 10 carbon atoms, each of the above R3, R4, R7, and R8 is a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group or a substituted or unsubstituted straight-chain or branched-chain alkyl group having 3 to 10 carbon atoms, and n is an integer from 1 to 10.

[0055] An assembly for a solar cell according to one embodiment of the present invention can prevent damage to the electron transport layer, improve transmittance, easily form a buffer layer, and improve conductivity.

[0056] FIG. 1 is a schematic diagram of a solar cell assembly (1) according to one embodiment of the present invention. With reference to FIG. 1, a solar cell assembly (1) according to one embodiment of the present invention will be described in detail.

[0057] According to one embodiment of the present invention, the solar cell assembly (1) is provided on the electron transport layer and includes a buffer layer containing the following chemical formula 1. As described above, by providing the buffer layer on the electron transport layer, the shock caused by sputtering during the process of manufacturing the first transparent electrode is mitigated, and at the same time, the structure is simplified by removing the existing inorganic buffer layer, and the manufacturing cost can be reduced. Furthermore, the stability of the solar cell can be improved, the power conversion efficiency can be improved, and the sensitivity to the thickness of the buffer layer can be reduced.

[0058] According to one embodiment of the present invention, the molecular weight of Formula 1 may be 400 g / mol or more and 800 g / mol or less. More specifically, the molecular weight of Formula 1 may be 540 g / mol or more and 680 g / mol or less. By controlling the molecular weight of Formula 1 within the above-described range, the shock caused by sputtering during the process of manufacturing the first transparent electrode can be mitigated, while the existing inorganic buffer layer can be removed to simplify the structure and reduce manufacturing costs. Furthermore, the stability of the solar cell can be improved, power conversion efficiency can be enhanced, and sensitivity to the thickness of the buffer layer can be reduced.

[0059] According to one embodiment of the present invention, the chemical formula 1 may be the chemical formula 2 or chemical formula 3 below. By selecting chemical formula 1 having a structure as described above, the shock caused by sputtering during the process of manufacturing the first transparent electrode can be mitigated, while the existing inorganic buffer layer can be removed to simplify the structure and reduce the manufacturing cost. Furthermore, the stability of the solar cell can be improved, the power conversion efficiency can be improved, and the sensitivity to the thickness of the buffer layer can be reduced.

[0060] [Chemical Formula 2]

[0061]

[0062] [Chemical Formula 3]

[0063]

[0064] According to one embodiment of the present invention, the electron transport layer may comprise a compound having 30 to 80 carbon atoms. More specifically, the electron transport layer may comprise a compound having 50 to 70 carbon atoms. More specifically, the electron transport layer may be a fullerene, a hydrogen bonding interface material, or an aliphatic amine-functionalized perylene diimide compound.

[0065] One embodiment of the present invention provides a perovskite solar cell (10) comprising the solar cell assembly (1), wherein a first transparent electrode layer (300); the buffer layer (200); the electron transport layer (100); a perovskite-based light absorption layer (400); a hole transport layer (500); and a second transparent electrode layer (600) are sequentially provided.

[0066] A perovskite solar cell according to one embodiment of the present invention can improve power conversion efficiency by achieving high conductivity and transparency, improve stability, and reduce sensitivity to changes in the thickness of the buffer layer.

[0067] FIG. 2 is a schematic diagram of a perovskite solar cell according to one embodiment of the present invention. With reference to FIG. 2, a perovskite solar cell according to one embodiment of the present invention will be described in detail.

[0068] According to one embodiment of the present invention, the perovskite solar cell comprises an assembly for the solar cell.

[0069] According to one embodiment of the present invention, the perovskite solar cell is provided with a first transparent electrode layer. As described above, by providing the first transparent electrode layer, the perovskite solar cell can receive light and improve power conversion efficiency.

[0070] According to one embodiment of the present invention, the perovskite solar cell is provided with the buffer layer. As described above, by providing the buffer layer in the perovskite solar cell, damage to the electron transport layer is prevented during sputtering performed to form the first transparent electrode, thereby improving power conversion efficiency and stability.

[0071] According to one embodiment of the present invention, the perovskite solar cell is provided with the electron transfer layer.

[0072] According to one embodiment of the present invention, the perovskite solar cell is provided with a perovskite-based light-absorbing layer. As described above, by providing the perovskite solar cell with a perovskite-based light-absorbing layer, the power conversion efficiency of the perovskite solar cell can be improved.

[0073] According to one embodiment of the present invention, the perovskite solar cell is provided with a hole transport layer.

[0074] According to one embodiment of the present invention, the perovskite solar cell is provided with a second transparent electrode layer. As described above, by providing the second transparent electrode layer, the perovskite solar cell can receive light from the rear side to improve power conversion efficiency.

[0075] According to one embodiment of the present invention, the perovskite solar cell comprises a first transparent electrode layer; a buffer layer; an electron transport layer; a perovskite-based light absorption layer; a hole transport layer; and a second transparent electrode layer in sequence. As described above, by forming the perovskite solar cell by sequentially stacking the first transparent electrode layer; the buffer layer; the electron transport layer; the perovskite-based light absorption layer; the hole transport layer; and the second transparent electrode layer, the shock caused by sputtering during the process of manufacturing the first transparent electrode can be mitigated, while the structure can be simplified by removing the existing inorganic buffer layer, and the manufacturing cost can be reduced. Furthermore, the stability of the solar cell can be improved, the power conversion efficiency can be enhanced, and the sensitivity to the thickness of the buffer layer can be reduced.

[0076] According to one embodiment of the present invention, each of the first transparent electrode layer and the second transparent electrode layer may comprise a material selected from the group consisting of instrinsic-ZnO (intrinsic zinc oxide, i-ZnO), indium tin oxide (ITO), indium zinc oxide (IZO), zinc tin oxide (ZTO), aluminum-doped zinc oxide (Al-doped ZnO: AZO), boron-doped zinc oxide (B-doped ZnO: BZO), fluorine-doped tin oxide (F-doped SnO: FTO), and combinations thereof. By selecting the material of each of the first transparent electrode layer and the second transparent electrode layer from the above, transparency can be improved and optical properties can be realized.

[0077] According to one embodiment of the present invention, the perovskite-based light absorption layer may comprise an organic-inorganic complex halide perovskite compound of the following chemical formula 4. By selecting the components included in the perovskite-based light absorption layer as described above, power conversion efficiency can be improved.

[0078] [Chemical Formula 4]

[0079] ABX3

[0080] The above A is one selected from the group consisting of CH3NH3, HC(NH2)2, Cs, Rb, and combinations thereof, the above B is one selected from the group consisting of Pb, Sn, and combinations thereof, and the above X is one selected from the group consisting of Cl, Br, I, and combinations thereof.

[0081] According to one embodiment of the present invention, in the above formula 4, A may be represented by the following formula 5, B may be represented by the following formula 6, and X3 may be represented by the following formula 7.

[0082] [Chemical Formula 5]

[0083] [CH3NH3] 1-a-b-c [HC(NH2)2] a Cs b Rb c

[0084] [Chemical Formula 6]

[0085] Pb 1-p Sn p

[0086] [Chemical Formula 7]

[0087] Cl 3-l-m B l I m

[0088] The above a is 0≤a≤1, the above b is 0≤b≤1, the above c is 0≤c≤1, the above p is 0≤a≤1, the above l is 0≤l≤3, and the above m is 0≤m≤3.

[0089] According to one embodiment of the present invention, the hole transport layer is NiOx(0 <x≤3), Me-4PACZ([4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid), MeO-2PACz([2-(3,6-Dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic Acid), MEO-4PACZ([4-(3,6-Dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid), 2PACz([2-(9H-Carbazol-9-yl)ethyl]phosphonic Acid), Br2-EPT, 폴리-[비스(4-페닐)(2,4,6-트리메틸페닐)아민](PTAA), 폴리아닐린, 폴리피롤, 폴리-3,4-에틸렌다이옥시싸이오펜-폴리스타이렌설포네이트(PEDOT:PSS), 스피로-미오타디(Spiro-MeOTAD), 폴리아닐린-캄포설폰산(PANI-CSA) 및 이들의 조합으로 이루어진 군으로부터 선택된 것을 포함하는 것을 포함하는 것일 수 있다. 상술한 것으로부터 상기 정공전달층의 재질을 선택함으로써, 에너지 준위를 조절하고, 광자 효율성을 향상시킬 수 있다.

[0090] Hereinafter, the present invention will be described in detail with reference to examples to specifically explain the invention. However, the embodiments according to the present invention may be modified in various different forms, and the scope of the present invention is not to be interpreted as being limited to the embodiments described below. The embodiments of this specification are provided to more completely explain the present invention to those with average knowledge in the art.

[0091] Example 1 (C60 / PDINN / IZO)

[0092] Indium zinc oxide (IZO) as the first transparent electrode layer; PDINN, a compound of Chemical Formula 2, as the buffer layer; and C as the electron transport layer. 60 (fullerene); a perovskite-based light absorption layer with a 1.55 eV bandgap Perovskite(Cs 0.05 MA 0.05 FA 0.9 Pb I 0.95 Br 0.05 ) ; A perovskite solar cell was fabricated by sequentially stacking Me-4PACz ([4-(3,6-dimethyl-9H-carbazol-9-yl)butyl] phosphonic acid) as a hole transport layer and indium zinc oxide (IZO) as a second transparent electrode layer.

[0093] Example 2 (PDINN)

[0094] Indium tin oxide (ITO) as the first transparent electrode layer; PDINN, a compound of Formula 2, as the buffer layer; C60 (fullerene) as the electron transport layer; and 1.55 eV Bandgap Perovskite (Cs 0.05 MA 0.05 FA 0.9 Pb I 0.95 Br 0.05 A perovskite solar cell was manufactured by sequentially stacking Me-4PACz as a hole transport layer and indium tin oxide (IZO) as a second transparent electrode layer.

[0095] Comparative Example 1 (C60 / SnO2 / IZO)

[0096] A perovskite solar cell was prepared in the same manner as in Example 1, except that the buffer layer in Example 1 was changed from the compound of Formula 2 to SnO2.

[0097] Comparative Example 2 (C60 / IZO)

[0098] A perovskite solar cell was manufactured in the same manner as in Example 1, except that the buffer layer was removed in Example 1.

[0099] Comparative Example 3 (PEIE)

[0100] A perovskite solar cell was prepared in the same manner as in Example 2, except that the buffer layer used in Example 2 was PEIE, a compound of Formula 8, instead of the compound of Formula 2.

[0101] [Chemical Formula 8]

[0102]

[0103] Comparative Example 4 (PEI)

[0104] A perovskite solar cell was prepared in the same manner as in Example 2, except that the buffer layer in Example 2 was replaced with PEI, the compound of Formula 9, instead of the compound of Formula 2.

[0105] [Chemical Formula 9]

[0106]

[0107] Experimental Example 1 (Short-circuit current measurement, J sc )

[0108] For the above Examples 1 and 2 and Comparative Examples 1 to 4, short-circuit current was measured under reverse scan (1.2 V to 0 V, step 0.02 V) and forward scan (0 V to 1.2 V, step 0.02 V) conditions with a delay time of 10 ms under AM1.5G conditions using a Class AAA optical simulator (MCscience).

[0109] Experimental Example 2 (Open-circuit voltage measurement, V oc )

[0110] For the above Examples 1 and 2 and Comparative Examples 1 to 4, the open-circuit voltage was measured under reverse scan (1.2 V to 0 V, step 0.02 V) and forward scan (0 V to 1.2 V, step 0.02 V) conditions with a delay time of 10 ms under AM1.5G conditions using a Class AAA optical simulator (MCscience).

[0111] Experimental Example 3 (Measurement of Filling Rate, FF, Fill Factor)

[0112] For the above Examples 1 and 2 and Comparative Examples 1 to 4, the fill rate was measured using a Class AAA optical simulator (MCscience) under AM1.5G conditions with a delay time of 10 ms under reverse scan (1.2 V to 0 V, step 0.02 V) and forward scan (0 V to 1.2 V, step 0.02 V).

[0113] Experimental Example 4 (Measurement of Power Conversion Efficiency, Efficiency)

[0114] For the above Examples 1 and 2 and Comparative Examples 1 to 4, power conversion efficiency was measured using a Class AAA optical simulator (MCscience) under AM1.5G conditions with a delay time of 10 ms under reverse scan (1.2 V to 0 V, step 0.02 V) and forward scan (0 V to 1.2 V, step 0.02 V).

[0115] <Evaluation>

[0116] Figure 3 is a graph showing the short-circuit current according to the open-circuit voltage of Example 1, Comparative Example 1, and Comparative Example 2. In Figure 3, RS represents reverse scan, and FS represents forward scan. Table 1 below shows the short-circuit current, open-circuit voltage, fill factor, and power conversion efficiency of Example 1, Comparative Example 1, and Comparative Example 2. Table 1 below shows the average values ​​of RS and FS.

[0117] Example 1 (C60 / PDINN / IZO) Comparative Example 1 (C60 / SnO2 / IZO) Comparative Example 2 (C60 / IZO) Short-circuit current, J sc (mA / cm 2 )23.5522.1023.48 Open circuit voltage, V oc (V)1.136 1.102 1.115 Fill Factor 0.795 0.789 0.725 Power Conversion Efficiency 21.26 19.23 18.93

[0118] Referring to Figure 3 and Table 1 above, it was confirmed that Example 1, which uses PDINN as a buffer layer, has higher short-circuit current, open-circuit voltage, fill factor, and power conversion efficiency compared to Comparative Example 1, which uses SnO2 as an inorganic buffer layer, and Comparative Example 2, which does not include a buffer layer. Figure 4 is a graph showing the short-circuit current according to the open-circuit voltage of Example 2, Comparative Example 3, and Comparative Example 4. In Figure 4, rev means reverse scan, and fwd means forward scan. Table 2 below shows the short-circuit current, open-circuit voltage, fill factor, and power conversion efficiency of Example 2, Comparative Example 3, and Comparative Example 4.

[0119] Example 2 (PDINN) Comparative Example 3 (PEIE) Comparative Example 4 (PEI) Average revfwd Average revfwd Average revfwd Short-circuit current, J sc (mA / cm 2 )23.5523.5623.5420.4520.4520.4521.0721.0821.07 Open-circuit voltage, V oc (V)1.1361.1381.1331.1331.1361.1281.101.101.09 Fill Factor, 0.7950.8060.7850.7550.7610.7530.720.730.70 Power Conversion Efficiency, 21.2621.6120.9317.4817.7017.3816.5216.8716.22

[0120] Referring to Figure 4 and Table 2 above, it was confirmed that Example 2 (using PDINN, a compound of Chemical Formula 2, as a buffer layer) exhibited higher short-circuit current, open-circuit voltage, fill factor, and power conversion efficiency compared to Comparative Example 3 (using PEIE, a compound of Chemical Formula 8, as a buffer layer) and Comparative Example 4 (using PEI, a compound of Chemical Formula 9, as a buffer layer). This was confirmed to be achieved due to the high conductivity and permeability characteristics of PDINN, a compound of Chemical Formula 2. Figure 5 is a graph showing the short-circuit current according to the open-circuit voltage after 24 hours, 72 hours, and 1536 hours of Example 2 under dark conditions. Figure 6 is a graph showing the short-circuit current according to the open-circuit voltage after 0 hours, 24 hours, and 144 hours of Comparative Example 3 under dark conditions. Specifically, the short-circuit current according to the open-circuit voltage was measured after aging the perovskite solar cell under the above dark conditions, in order to evaluate the stability of the perovskite solar cell. Furthermore, FIG. 7 is a graph showing the power conversion efficiency over time under the dark conditions of Example 2 and Comparative Example 3.

[0121] Table 3 below shows the short-circuit current, open-circuit voltage, fill factor, and power conversion efficiency after 24 hours, 72 hours, and 1536 hours of dark conditions for Example 2.

[0122] Example 2 (PDINN) 24 hours elapsed 72 hours elapsed 15 36 hours elapsed Average RSFS Average RSFS Average RSFS Short-circuit current, J sc (mA / cm 2 )23.1323.1423.1223.1023.0623.1423.0923.0823.11 Open-circuit voltage, V oc(V)1.124 1.125 1.122 1.136 1.138 1.133 1.115 1.116 1.114 Fill Factor 0.79 30.80 0.78 60.79 50.80 60.78 50.74 70.75 90.736 Power Conversion Efficiency 20.6 120.8 320.40 20.8 521.15 20.57 19.2 419.56 18.95

[0123] Table 4 below shows the short-circuit current, open-circuit voltage, filling rate, and power conversion efficiency after 0 hours, 24 hours, and 144 hours have elapsed under the dark conditions of Comparative Example 3.

[0124] Comparative Example 3 (PEIE) 0 elapsed time 24 elapsed time 144 elapsed time Average RSFS Average RSFS Average RSFS Short-circuit current, J sc (mA / cm 2 )20.4520.4520.4520.6220.5920.6520.9520.9420.96 Open-circuit voltage, V oc (V)1.1331.1361.1281.1061.1061.1061.0931.0911.096 Fill Factor 0.755 0.761 0.753 0.501 0.492 0.51 0.434 0.423 0.444 Power Conversion Efficiency 17.481 7.701 7.381 1.431 1.201 1.66 9.93 9.671 0.20

[0125] Referring to Figures 5 and 6 and Tables 3 and 4 above, it was confirmed that Example 2 (using PDINN, the compound of Chemical Formula 2, as a buffer layer) showed a lower rate of decrease in short-circuit current and open-circuit voltage even when aged under dark conditions compared to Comparative Example 3 (using PEIE, the compound of Chemical Formula 8, as a buffer layer). Furthermore, referring to Figure 7 and Tables 3 and 4 above, it was confirmed that Example 2 (using PDINN, the compound of Chemical Formula 2, as a buffer layer) maintained a higher power conversion efficiency for a longer period of time even when aged under dark conditions compared to Comparative Example 3 (using PEIE, the compound of Chemical Formula 8, as a buffer layer). This is presumed to be due to the use of a polar solvent in the manufacturing process of Comparative Example 3, which caused damage to the perovskite light absorption layer.

[0126] FIG. 8 is a graph showing the power conversion efficiency according to the concentration of the precursor solution for forming the buffer layer of Example 2 and Comparative Example 4. Specifically, FIG. 8 is a graph showing the power conversion efficiency when the concentration of the precursor solution for forming the buffer layer of Example 2 and Comparative Example 4 is 0.25 mg / ml, 0.50 mg / ml, and 0.75 mg / ml.

[0127] Furthermore, Table 5 below shows the short-circuit current, open-circuit voltage, filling rate, and power conversion efficiency for Example 2 when the optimal concentration of the buffer layer precursor solution is 0.25 mg / ml, 0.50 mg / ml, and 0.75 mg / ml.

[0128] Example 2 (PDINN) 0.25 mg / ml 0.5 mg / ml 0.75 mg / ml Average RSFS Average RSFS Average RSFS Short-circuit current, J sc (mA / cm 2 )23.5523.5623.5423.5623.5823.5523.5523.5523.54Open circuit voltage, V oc(V)1.136 1.138 1.133 1.131 1.132 1.130 1.122 1.124 1.120 Fill Factor 0.795 0.806 0.785 0.795 0.802 0.788 0.794 0.803 0.787 Power Conversion Efficiency 21.26 21.6 120.93 21.19 21.4 120.97 20.98 21.24 20.75

[0129] In addition, Table 6 below shows the short-circuit current, open-circuit voltage, filling rate, and power conversion efficiency for Comparative Example 4 when the optimal concentration of the buffer layer precursor solution is 0.25 mg / ml, 0.50 mg / ml, and 0.75 mg / ml.

[0130] Comparative Example 4 (PEI) 0.25 mg / ml 0.5 mg / ml 0.75 mg / ml Average RSFS Average RSFS Average RSFS Short-circuit current, J sc (mA / cm 2 )21.0721.0821.0721.3921.4021.3819.3819.4019.35 Open-circuit voltage, V oc (V)1.10 1.10 1.09 1.03 1.05 1.01 0.85 0.89 0.82 Fill Factor, 0.72 0.73 0.70 0.65 0.69 0.63 0.41 0.41 0.42 Power Conversion Efficiency, 16.52 16.87 16.22 14.43 15.49 13.70 6.85 7.11 6.64

[0131] Referring to Figure 8 and Tables 5 and 6, it was confirmed that in Example 2, the changes in short-circuit current, open-circuit voltage, fill factor, and power conversion efficiency were small even when the optimal concentration of the buffer layer precursor solution increased, whereas in Comparative Example 4, the changes in short-circuit current, open-circuit voltage, fill factor, and power conversion efficiency were larger compared to Example 2. This confirms that in Comparative Example 4, where the buffer layer is PEI, the power conversion efficiency is reduced because it performs the role of an insulating layer rather than a buffer layer.

[0132] [Explanation of the symbol]

[0133] 1: Assembly for solar cells

[0134] 10: Perovskite solar cells

[0135] 100: Electron transport layer

[0136] 200: Buffer layer

[0137] 300: First transparent electrode layer

[0138] 400: Perovskite-based light absorption layer

[0139] 500: Hole transport layer

[0140] 600: Second transparent electrode layer

Claims

1. Electron transport layer; and An assembly for a solar cell comprising a buffer layer provided on the electron transport layer and containing the following chemical formula 1: [Chemical Formula 1] Each of the above R1, R2, R5, and R6 is a substituted or unsubstituted methylene group or a substituted or unsubstituted straight-chain or branched-chain alkylene group having 2 to 10 carbon atoms, and Each of the above R3, R4, R7, and R8 is a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, or a substituted or unsubstituted straight-chain or branched-chain alkyl group having 3 to 10 carbon atoms, and The above n is an integer between 1 and 10.

2. In Claim 1, An assembly for a solar cell having a molecular weight of Chemical Formula 1 of the above formula of 400 g / mol or more and 800 g / mol or less.

3. In Claim 1, An assembly for a solar cell in which the above chemical formula 1 is the following chemical formula 2 or chemical formula 3: [Chemical Formula 2] [Chemical Formula 3] 4. In Claim 1, An assembly for a solar cell in which the electron transport layer comprises a compound having 30 to 80 carbon atoms.

5. Comprising an assembly for a solar cell according to any one of claims 1 to 4, A perovskite solar cell having a first transparent electrode layer; the buffer layer; the electron transport layer; the perovskite-based light absorption layer; the hole transport layer; and a second transparent electrode layer sequentially provided.

6. In Claim 5, A perovskite solar cell wherein each of the first transparent electrode layer and the second transparent electrode layer comprises a material selected from the group consisting of instrinsic-ZnO (intrinsic zinc oxide, i-ZnO), indium tin oxide (ITO), indium zinc oxide (IZO), zinc tin oxide (ZTO), aluminum-doped zinc oxide (Al-doped ZnO: AZO), boron-doped zinc oxide (B-doped ZnO: BZO), fluorine-doped tin oxide (F-doped SnO: FTO), and combinations thereof.

7. In Claim 5, A perovskite solar cell in which the above perovskite-based light absorption layer comprises an organic-inorganic complex halide perovskite compound of the following chemical formula 4: [Chemical Formula 4] ABX3 The above A is one selected from the group consisting of CH3NH3, HC(NH2)2, Cs, Rb, and combinations thereof, and The above B is one selected from the group consisting of Pb, Sn, and combinations thereof, and The above X is one selected from the group consisting of Cl, Br, I and combinations thereof.

8. In Claim 7, In the above chemical formula 4, The above A is represented by the following chemical formula 5, and The above B is represented by the following chemical formula 6, and The above X3 is a perovskite solar cell represented by the following chemical formula 7: [Chemical Formula 5] [CH3NH3] 1-a-b-c [HC(NH2)2] a Cs b Rb c [Chemical Formula 6] Pb 1-p Sn p [Chemical Formula 7] Cl 3-l-m B l I m The above a is 0≤a≤1, the above b is 0≤b≤1, and the above c is 0≤c≤1, and The above p is 0≤a≤1, and The above l is 0≤l≤3 and the above m is 0≤m≤3.

9. In Claim 5, The hole transport layer above is NiOx(0 <x≤3), Me-4PACz([4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid), MeO-2PACz([2-(3,6-Dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic Acid), MEO-4PACZ([4-(3,6-Dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid), 2PACz([2-(9H-Carbazol-9-yl)ethyl]phosphonic Acid), Br2-EPT, 폴리-[비스(4-페닐)(2,4,6-트리메틸페닐)아민](PTAA), 폴리아닐린, 폴리피롤, 폴리-3,4-에틸렌다이옥시싸이오펜-폴리스타이렌설포네이트(PEDOT:PSS), 스피로-미오타디(Spiro-MeOTAD), 폴리아닐린-캄포설폰산(PANI-CSA) 및 이들의 조합으로 이루어진 군으로부터 선택된 것을 포함하는 것인 페로브스카이트 태양전지.

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