Perovskite solar cell and manufacturing method thereof

Abstract

The present invention relates to a perovskite solar cell in which an electron transport buffer layer having a three-layer structure is introduced between a perovskite light absorption layer and an electron transport layer, and a method for manufacturing the same.

Description

Technical Field

[0001] This invention relates to a perovskite solar cell comprising an additive in a hole transport layer and introducing an intermediate layer between the hole transport layer and the perovskite light-absorbing layer, and a method for manufacturing the same. Background Technology

[0002] To address the global environmental problems caused by the depletion and use of fossil fuels, research is actively underway on renewable and clean alternative energy sources such as solar, wind, and hydropower.

[0003] Among these, there is a significant increase in attention paid to solar cells, which directly convert sunlight into electrical energy. Here, a solar cell refers to a battery that generates current and voltage by utilizing the photovoltaic effect—the process of absorbing light energy from sunlight to produce electrons and holes.

[0004] Currently, it is possible to manufacture NP-diode-based silicon (Si) single-crystal solar cells with light conversion efficiencies exceeding 20%, and these are actually used for solar power generation. Solar cells using compound semiconductors such as gallium arsenide (GaAs) with even higher conversion efficiencies also exist. However, because these inorganic semiconductor-based solar cells require highly purified materials to achieve high efficiency, a significant amount of energy is consumed in refining the raw materials, and expensive processing equipment is required in manufacturing single crystals or thin films using these raw materials. This limits the reduction in the manufacturing cost of solar cells, which has been an obstacle to their large-scale utilization.

[0005] Therefore, in order to manufacture solar cells at low cost, it is necessary to significantly reduce the cost of materials or manufacturing processes used as the core components of solar cells. As an alternative to inorganic semiconductor-based solar cells, perovskite solar cells that can be manufactured using low-cost materials and processes are being researched.

[0006] Recently, perovskite solar cells using a halide compound (NH3CH3)PbX3 (X = I, Br, Cl) with a perovskite structure as a photoactive agent have been developed and are under commercialization research. The general structural formula of the perovskite structure is ABX3, in which the anion is located at the X site, the large cation is located at the A site, and the small cation is located at the B site.

[0007] Meanwhile, perovskite solar cells are being developed in the form of PIN perovskite single solar cells or double-ended perovskite / silicon tandem solar cells. In the case of double-ended perovskite / silicon tandem solar cells, a composite layer is formed on the glass and the lower silicon solar cell, and then an upper perovskite solar cell layer, such as a hole transport layer, a perovskite light absorption layer, an electron transport layer, and a transparent electrode, is formed sequentially to manufacture a double-ended perovskite / silicon tandem solar cell.

[0008] In traditional technologies, the hole transport layer can be formed using either deposition or solution processing. However, if the hole transport layer is formed using deposition, not only does the manufacturing cost increase, but various additives are also required in target development to improve performance. Furthermore, if the hole transport layer is formed using solution processing, there is a problem of uneven hole transport layer formation compared to deposition, which leads to a decrease in the performance of perovskite solar cells. Summary of the Invention Technical issues

[0009] This invention is designed to overcome the above-mentioned problems and aims to provide a perovskite solar cell and a method for manufacturing the same. It not only improves the characteristics of the hole transport layer by including additives in the hole transport layer and introducing an intermediate layer between the hole transport layer and the perovskite light absorption layer, but also improves the performance of the perovskite solar cell by forming the hole transport layer into a uniform thin film.

[0010] In addition, the present invention aims to provide a perovskite solar cell and a method for manufacturing the same, which forms a hole transport layer through a solution process, making it more economical than perovskite solar cells obtained through a deposition process. Technical solutions

[0011] To address the aforementioned problems, the perovskite solar cell of the present invention may include a laminate in which a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated. An intermediate layer may be formed between the hole transport layer and the perovskite light-absorbing layer, and the hole transport layer may include an additive.

[0012] In a preferred embodiment of the present invention, the additive may include one or more selected from alkali metals and alkaline earth metals.

[0013] In a preferred embodiment of the invention, the hole transport layer may include 1 mol% to 7 mol% of additives based on the total mol% amount.

[0014] In a preferred embodiment of the present invention, the intermediate layer may include a self-assembled monolayer comprising carbazole and phosphonic acid.

[0015] In a preferred embodiment of the present invention, the hole transport layer and the intermediate layer may have a thickness ratio of 1:0.05 to 1:0.25.

[0016] In a preferred embodiment of the present invention, the perovskite solar cell of the present invention may be a pin-structured perovskite solar cell, a nip-inverted perovskite solar cell, a tandem perovskite solar cell, or a tandem silicon / perovskite heterojunction solar cell.

[0017] Meanwhile, the method for manufacturing perovskite solar cells according to the present invention may include: a first step of forming a hole transport layer on top of a transparent conductive layer by solution processing, a second step of forming an intermediate layer on top of the hole transport layer, and a third step of forming a perovskite light-absorbing layer on top of the intermediate layer, wherein the hole transport layer may include additives.

[0018] In a preferred embodiment of the present invention, the additive may include one or more selected from alkali metals and alkaline earth metals.

[0019] In a preferred embodiment of the invention, the hole transport layer may include 1 mol% to 7 mol% of additives based on the total mol% amount.

[0020] In a preferred embodiment of the present invention, the intermediate layer may include a self-assembled monolayer comprising carbazole and phosphonic acid.

[0021] Furthermore, the tandem silicon / perovskite heterojunction solar cell of the present invention is a heterojunction solar cell. In the heterojunction solar cell, the solar cell, transparent conductive layer, hole transport layer, intermediate layer, perovskite light absorption layer, electron transport layer, transparent electrode and metal electrode are laminated in sequence. The hole transport layer may include additives.

[0022] In a preferred embodiment of the present invention, the additive may include one or more selected from alkali metals and alkaline earth metals, and the intermediate layer may include a self-assembled monolayer comprising carbazole and phosphonic acid.

[0023] In a preferred embodiment of the invention, the hole transport layer may include 1 mol% to 7 mol% of additives based on the total mol% amount.

[0024] In a preferred embodiment of the present invention, the solar cell may be a polycrystalline silicon solar cell, a crystalline silicon solar cell, a perovskite solar cell, a gallium arsenide (GaAs) solar cell, a cadmium telluride (CdTe) solar cell, a CIGS (CuInGaSe) solar cell, a CZTS (Cu2ZnSnS4) solar cell, an organic solar cell, a fuel-sensitized solar cell, or a group 3 to group 5 compound solar cell. Beneficial effects

[0025] The perovskite solar cell of the present invention improves not only the characteristics of the hole transport layer by including additives in the hole transport layer and introducing an intermediate layer between the hole transport layer and the perovskite light absorption layer, but also improves the performance of the perovskite solar cell by forming the hole transport layer into a uniform thin film.

[0026] Furthermore, the method for manufacturing perovskite solar cells according to the present invention forms a hole transport layer through a solution process, which is more economical than performing a deposition process. Attached Figure Description

[0027] Figure 1 A graph showing the intensity of the change in binding energy at the surface of the hole transport layer in each of the tandem silicon / perovskite heterojunction solar cells fabricated according to Examples 1 and 2 and Comparative Examples 1 and 2, as measured by photoelectron spectroscopy (XPS).

[0028] Figure 2 Condition 1 (indicated by NiO) is shown for the tandem silicon / perovskite heterojunction solar cell fabricated in Example 1. x Under conditions 1, 2 (indicated as 2PACs) and 4 (indicated as erased PSK), the Cs 3d at the surface 5 / 2 The intensity variation curve, such as that measured by photoelectron spectroscopy (XPS). Detailed Implementation

[0029] The invention will be described in more detail below.

[0030] Existing perovskite solar cells can form hole transport layers using either deposition or solution processing. However, if the hole transport layer is formed via deposition, not only does the manufacturing cost increase, but various additives are also required in target development to improve performance. Furthermore, if the hole transport layer is formed via solution processing, there is a problem of uneven hole transport layer formation compared to deposition, which leads to performance degradation in perovskite solar cells.

[0031] Therefore, the present invention relates to perovskite solar cells, which not only improve the characteristics of the hole transport layer by including additives in the hole transport layer and introducing an intermediate layer between the hole transport layer and the perovskite light absorption layer, but also improve the performance of the perovskite solar cells by forming the hole transport layer into a uniform thin film.

[0032] The perovskite solar cell of the present invention can be a pin-structured perovskite solar cell, a nip-inverted perovskite solar cell, a tandem perovskite solar cell, or a tandem silicon / perovskite heterojunction solar cell, preferably a tandem silicon / perovskite heterojunction solar cell, and can be a solar cell comprising a laminate in which a hole transport layer (HTL), a perovskite light-absorbing layer, an electron transport layer (ETL), a transparent electrode, and a metal electrode are laminated sequentially.

[0033] In addition, the perovskite solar cell of the present invention may have an intermediate layer formed between the hole transport layer and the perovskite light absorption layer.

[0034] For example, in a preferred embodiment, when the perovskite solar cell of the present invention is a tandem silicon / perovskite heterojunction solar cell, it can be a heterojunction solar cell. In the heterojunction solar cell, the solar cell, transparent conductive layer, hole transport layer, intermediate layer, perovskite light absorption layer, electron transport layer, transparent electrode and metal electrode are laminated in sequence.

[0035] Solar cells can be polycrystalline silicon solar cells, crystalline silicon solar cells, perovskite solar cells, gallium arsenide (GaAs) solar cells, cadmium telluride (CdTe) solar cells, CIGS (CuInGaSe) solar cells, CZTS (Cu2ZnSnS4) solar cells, organic solar cells, fuel-sensitized solar cells, or compound solar cells of groups 3 to 5.

[0036] In addition, there is no particular limitation on the thickness of the solar cell, but it is preferably 140 μm to 250 μm, more preferably 160 μm to 200 μm.

[0037] The transparent conductive layer is a layer that induces the recombination of electrons and holes in the solar cell and the perovskite light-absorbing layer described later. The transparent conductive layer can be a transparent thin film deposited thereon with ITO (indium tin oxide), FTO (fluorine-doped tin oxide), ATO (Sb2O3-doped tin oxide), GTO (gallium-doped tin oxide), ZTO (zinc oxide doped tin), ZTO:Ga (gallium-doped ZTO), IGZO (indium gallium zinc oxide), IZO (indium zinc oxide), or AZO (aluminum-doped zinc oxide).

[0038] Furthermore, as an example of forming a transparent conductive layer, when using a silicon solar cell doped with n-type or p-type impurities as a solar cell, the silicon solar cell doped with n-type or p-type impurities is treated with hydrofluoric acid to remove SiO. x An oxide film is formed, and then residual hydrofluoric acid is removed using ultrapure water. A transparent conductive layer can then be formed on top of the solar cell, where the oxide film has been removed, using a sputtering process.

[0039] In addition, there is no particular limitation on the thickness of the transparent conductive layer, but it is preferably 5 nm to 50 nm thick, more preferably 15 nm to 25 nm thick.

[0040] Hole transport layer (HTL) is a layer that transports holes formed in the perovskite light-absorbing layer (described later) while blocking the movement of electrons, and may include inorganic and / or organic hole transport materials.

[0041] In this case, inorganic hole transport materials may include those selected from nickel oxide (NiO). xOne or more of CuSCN, CuCrO2, CuI, MoO and V2O5, with nickel oxide (NiO) being the most preferred. x ).

[0042] Additionally, organic hole transport materials may include one or more of the following: carbazole derivatives, polyarylalkane derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrene-anthracene derivatives, fluorene derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, aniline compounds, aromatic dimethylene compounds, porphyrin compounds, phthalocyanine compounds, polythiophene derivatives, polypyrrole derivatives, poly(p-phenylenevinyl) derivatives, pentadiene, coumarin 6 (coumarin 6,3-(2-benzothiazolyl)-7-(diethylamino)coumarin), ZnPC (zinc phthalocyanine), CuPC (copper phthalocyanine), TiOPC (titanium oxide phthalocyanine), spiro-MeOT AD (2,2',7,7'-tetratetra(N,N-p-dimethoxyphenylamino)-9,9'-spirodifluorene), F16CuPC (copper(II)1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecylfluoro-29H,31H-phthalocyanine), SubPc (boronylphthalocyanine chloride) and N3 (cis-di(thiocyano)-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid)-ruthenium(II), P3HT (poly[3-hexylthiophene]), MDMO-PPV (poly[2-methoxy-5-(3',7'-dimethyloctyloxy)]-1,4-phenylenevinylene), MEH-PPV (poly[2-methoxy-5-(3',7'-dimethyloctyloxy)]-1,4-phenylenevinylene), -(2''-ethylhexyloxy)-p-phenylenevinylene]), P3OT (poly(3-octylthiophene)), POT (poly(octylthiophene)), P3DT (poly(3-dodecylthiophene)), P3DDT (poly(3-dodecylthiophene), PPV (poly(p-phenylenevinylene)), TFB (poly(9,9'-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine), polyaniline, spiro-MeOTAD ([2,22',7,77'-tetratetra(N,N-dimethoxyphenyl)-9,9,9''-spirodifluoro]), PCPDTBT (poly[2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl-4H-cyclopentadienyl[2 ,1-b:3,4-b']dithiophene-2,6-diyl]], Si-PCPDTBT (poly[(4,4''-bis(2-ethylhexyl)dithiophene[3,2-b:2'',3''-d]silazanecyclopentadiene)-2,6-diyl-alternating-(2,1,3-benzothiadiazole)-4,7-diyl]), PBDTTPD (poly((4,8-diethylhexyloxy), PFDTBT (poly[2,7-(9-(2-ethylhexyl)-9-hexyl-fluorene)-alternating-5,5-(4',7,-di-2-thiophene-2',1',3'-benzothiadiazole)]), PFO-DBT (poly[2,7-9,9-(dioctylfluorene)-alternating-5,5-(4',7'-Di-2-thienyl-2',1',3'-benzothiadiazole)]), PSiFDTBT (poly[(2,7-dioctylsilfluorene)-2,7-diyl-alternating-(4,7-bis(2-thienyl)-2,1,3-benzothiadiazole)-5,5''-diyl]), PCDTBT (poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thienyldiyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thienyldiyl]), PFB (poly(9,9''-dioctyl) Fluorene-co-bis(N,N''-(4,butylphenyl))bis(N,N''-phenyl-1,4-phenylene)diamine), F8BT (poly(9,9''-dioctylfluorene-co-benzothiadiazole), PEDOT (poly(3,4-ethylenedioxythiophene)), PEDOT:PSS poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate), PTAA (poly(triarylamine)), 2-PACz, MeO-2PACz, Br-2PACz, Me-4PACz, MeO-4PACz and 6-PACz.

[0043] Furthermore, examples of methods for forming the hole transport layer include coating and vacuum evaporation, and examples of coating include gravure coating, bar coating, printing, spraying, spin coating, immersion coating, and die coating. Preferably, the hole transport layer can be formed by a deposition process or a solution process, and most preferably, the hole transport layer can be formed by spin coating in a solution process.

[0044] Meanwhile, the hole transport layer of the present invention may include additives. The additives may include one or more selected from alkali metals and alkaline earth metals, preferably one or more selected from cesium, lithium, sodium, potassium, rubidium, zinc and molybdenum, and more preferably cesium.

[0045] Specifically, the hole transport layer may include an additive in an amount of 1 mol% to 7 mol%, preferably 1 mol% to 4 mol%, more preferably 1.5 mol% to 2.5 mol%, based on the total mol%. If the additive content is less than 1 mol%, there may be a problem of covering the entire hole transport layer; if the additive content exceeds 7 mol%, there may be a problem of hindering charge flow.

[0046] In addition, there is no particular limitation on the thickness of the hole transport layer, but it is preferably 5 nm to 40 nm thick, and more preferably 10 nm to 30 nm thick.

[0047] The intermediate layer may include a self-assembled monolayer comprising carbazole and phosphonic acid, preferably comprising one or more selected from 2PACz ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid), Me-2PACz, MeO-2PACz, 4PACz, Me-4PACz and MeO-4PACz, and preferably comprising 2PACz.

[0048] Methods for forming the intermediate layer include coating and vacuum evaporation, and examples of coating methods include gravure coating, bar coating, printing, spraying, spin coating, immersion coating, and mold coating. Preferably, the intermediate layer can be formed by deposition or solution processing, and most preferably, the intermediate layer can be formed by spin coating in a solution process.

[0049] There is no particular limitation on the thickness of the intermediate layer, but it is preferably 0.1 nm to 10 nm, more preferably 1 nm to 5 nm.

[0050] Meanwhile, the thickness ratio of the hole transport layer to the intermediate layer can be from 1:0.05 to 1:0.25, preferably from 1:0.1 to 1:0.2, and more preferably from 1:0.13 to 1:0.17. If the thickness ratio is less than 1:0.05, there may be a problem of covering the entire hole transport layer, and if it exceeds 1:0.25, there may be a problem of over-coating, which may hinder charge flow.

[0051] The perovskite light-absorbing layer may include a general perovskite material used in the light-absorbing layer of a solar cell, and as a preferred example, it may include a perovskite material represented by the following chemical formula 1.

[0052] [Chemical Formula 1]

[0053] CMX3

[0054] In the above chemical formula 1, C is a monovalent cation, which may include amines, ammonium, Group 1 metals, Group 2 metals and / or other cations or cation-like compounds. Preferably, it may be formamidine acetate (FA), methylamine hydrochloride (MA. methylamine hydrochloride), FAMA, CsFAMA, CsFA or N(R). 4+ (Here, R can be the same or different groups, and R is a straight-chain alkyl group with 1 to 5 carbon atoms, a branched alkyl group with 3 to 5 carbon atoms, a phenyl group, an alkylphenyl group, an alkoxyphenyl group, or an alkyl halide.)

[0055] In addition, M in Formula 1 is a divalent cation, which may include one or two selected from Fe, Co, Ni, Cu, Sn, Pb, Bi, Ge, Ti, Eu and Zr.

[0056] Additionally, X in Formula 1 is a monovalent anion, which may include one or more halide elements selected from F, Cl, Br, and I and / or Group 16 anions. As a preferred example, X may be IxBr 3-x (0≤x≤3).

[0057] Alternatively, a preferred embodiment of chemical formula 1 may be FAPbI. x Br 3-x (0≤x≤3), MAPbI x Br 3-x (0≤x≤3), CSFAPbI x Br 3-x (0≤x≤3), CSMAFAPbI x Br 3-x (0≤x≤3), CH3NH3PbX3 (X=Cl, Br, I, BrI2 or Br2I), CH3NH3SnX3 (X=Cl, Br or I), CH(=NH)NH3PbX3 (X=Cl, Br, I, BrI2 or Br2I) or CH(=NH)NH3SnX3 (X=Cl, Br or I).

[0058] Meanwhile, in the perovskite solar cell of the present invention, the perovskite light-absorbing layer can be a single layer composed of the same perovskite material, or a multilayer structure composed of multiple layers of different perovskite materials. Furthermore, within the light-absorbing layer composed of a perovskite material, a heterogeneous perovskite material different from the perovskite material having a columnar, plate-like, needle-like, linear, or rod-like crystal columnar shape may be included.

[0059] In addition, methods for forming perovskite light-absorbing layers include coating and vacuum evaporation, and examples of coating methods include gravure coating, rod coating, printing, spraying, spin coating, immersion coating, inkjet coating and mold coating.

[0060] An electron transport layer (ETL) is a layer that transports electrons formed in a perovskite light-absorbing layer while blocking the movement of holes, and may include components selected from tin oxide (SnO). x Nickel oxide (NiO) x One or more of the following: tin oxide (SnO2), titanium dioxide (TiO2), zinc oxide (ZnO), barium tin oxide (BaSnO3), niobium hydroxide (NbOH), and niobium pentoxide (Nb2O5).

[0061] In addition, methods for forming the electron transport layer include coating, ALD deposition and / or vacuum deposition, and examples of coating methods include gravure coating, bar coating, printing, spraying, spin coating, immersion coating and mold coating.

[0062] In addition, there is no particular limitation on the thickness of the electron transport layer, but it is preferably 3 nm to 30 nm in average thickness, more preferably 3 nm to 15 nm, and even more preferably 8 nm to 13 nm.

[0063] A transparent electrode can be formed on top of the electron transport layer by a deposition process. In this case, the deposition can be performed using conventional deposition processes used in the art, and preferably, the deposition process can be performed using a sputtering method.

[0064] Alternatively, the transparent electrode can be a transparent thin film on which ITO (indium tin oxide), FTO (fluorine-doped tin oxide), ATO (Sb2O3-doped tin oxide), GTO (gallium-doped tin oxide), ZTO (tin-doped zinc oxide), ZTO:Ga (gallium-doped ZTO), IGZO (indium gallium zinc oxide), IZO (indium-doped zinc oxide), or AZO (aluminum-doped zinc oxide) is deposited.

[0065] In addition, there is no particular limitation on the thickness of the transparent electrode, but it is preferably 50 nm to 200 nm thick, more preferably 50 nm to 140 nm thick.

[0066] Metal electrodes can be formed by patterning a metal material on top of a transparent electrode. Specifically, the patterning process mainly consists of deposition, exposure (photolithography), and etching. Metal electrodes can be formed on top of a transparent electrode by spreading a thin film of metal material on one surface of a substrate, printing a pattern through exposure, and then removing unwanted portions. Alternatively, patterning can be performed using screen printing with a metal paste containing the metal material.

[0067] In this case, the metallic material may include one or more selected from Pt, Au, Ni, Cu, Ag, In, Ru, Pd, Rh, Ir, Os, C and conductive polymers.

[0068] In addition, there is no particular limitation on the thickness of the metal electrode, but it is preferably between 50 nm and 2.5 μm.

[0069] Meanwhile, the method for manufacturing perovskite solar cells according to the present invention may include: a first step of forming a hole transport layer on top of a transparent conductive layer by a solution process; a second step of forming an intermediate layer on top of the hole transport layer; and a third step of forming a perovskite light-absorbing layer on top of the intermediate layer. In this case, the hole transport layer may include additives. The additives may include one or more selected from alkali metals and alkaline earth metals, preferably, they may include one or more selected from cesium, lithium, sodium, potassium, rubidium, zinc and molybdenum, more preferably, they may include cesium.

[0070] Specifically, the hole transport layer may include additives ranging from 1 mol% to 7 mol%, preferably from 1 mol% to 4 mol%, and more preferably from 1.5 mol% to 2.5 mol% based on the total mol%.

[0071] Additionally, the intermediate layer may include a self-assembled monolayer comprising carbazole and phosphonic acid. Preferably, the self-assembled monolayer may include one or more selected from 2PACz ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid), Me-2PACz, MeO-2PACz, 4PACz, Me-4PACz, and MeO-4PACz. Preferably, the self-assembled monolayer may include 2PACz.

[0072] The invention will be described in more detail below by way of examples, but the following examples do not limit the scope of the invention and should be interpreted as helpful in understanding the invention.

[0073] Example 1: Fabrication of tandem silicon / perovskite heterojunction solar cells

[0074] (1) Prepare silicon solar cells (180 μm thick) doped with n-type or p-type impurities, and remove SiO by hydrofluoric acid treatment. x An oxide film is formed, and residual hydrofluoric acid is removed using ultrapure water. A 20 nm thick transparent conductive layer (ITO) is then formed on top of the silicon solar cell after the oxide film has been removed using a sputtering process.

[0075] (2) Next, NiO including additives is spin-coated on top of the transparent conductive layer. x Nanocolloidal solutions are used to form a 20 nm thick hole transport layer (NiO). x + Additives). In this case, cesium is used as an additive, and the cesium content is 2 mol% based on the total mol% of the hole transport layer.

[0076] (3) Next, 2PACz ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) is spin-coated onto the top of the hole transport layer to form an intermediate layer with an average thickness of 3 nm.

[0077] (4) Next, a perovskite crystal structure (Cs) will be formed. 0.2 Fa 0.8 Pb(I) 0.8 Br 0.2 100 μl of the 1.3 M perovskite precursor solution was dropped onto the upper part of the intermediate layer. After spin-coating at 5000 rpm for 30 seconds in 99% pure nitrogen environment, it was then heat-treated at 100°C for 20 minutes to form a 500 nm thick perovskite light-absorbing layer.

[0078] (5) Next, an electron transport layer (SnO2) with an average thickness of 10 nm is formed on top of the perovskite light-absorbing layer by atomic layer deposition (ALD).

[0079] (6) Next, a transparent electrode (ITO) with a thickness of 55 nm is formed on the top of the electron transport layer by sputtering.

[0080] (7) Finally, in 1×10 -7 Under pressure, silver (Ag) is deposited on top of the transparent electrode to form a metal electrode with a thickness of 100 nm, thereby fabricating a tandem silicon / perovskite heterojunction solar cell. In the tandem silicon / perovskite heterojunction solar cell, the silicon solar cell, transparent conductive layer, hole transport layer, intermediate layer, perovskite light absorption layer, electron transport layer, transparent electrode and metal electrode are laminated in sequence.

[0081] Example 2: Fabrication of tandem silicon / perovskite heterojunction solar cells

[0082] A tandem silicon / perovskite heterojunction solar cell was fabricated in the same manner as in Example 1, wherein a silicon solar cell, a transparent conductive layer, a hole transport layer, an intermediate layer, a perovskite light-absorbing layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated in the tandem silicon / perovskite heterojunction solar cell. However, unlike in Example 1, when the hole transport layer is formed, the cesium content is 5 mol% based on the total mol% of the hole transport layer.

[0083] Comparative Example 1: Fabrication of Tandem Silicon / Perovskite Heterojunction Solar Cells

[0084] (1) Prepare silicon solar cells (180 μm thick) doped with n-type or p-type impurities, and remove SiO by hydrofluoric acid treatment. xAn oxide film is formed, and residual hydrofluoric acid is removed using ultrapure water. A 20 nm thick transparent conductive layer (ITO) is then formed on top of the silicon solar cell after the oxide film has been removed using a sputtering process.

[0085] (2) Next, NiO is spin-coated on top of the transparent conductive layer. x Nanocolloidal solutions are used to form a 20 nm thick hole transport layer (NiO). x ).

[0086] (3) Next, 2PACz ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) is spin-coated onto the top of the hole transport layer to form an intermediate layer with an average thickness of 3 nm.

[0087] (4) Next, a perovskite crystal structure (Cs) will be formed. 0.2 Fa 0.8 Pb(I) 0.8 Br 0.2 100 μl of the 1.3 M perovskite precursor solution was dropped onto the upper part of the intermediate layer. After spin-coating at 5000 rpm for 30 seconds in 99% pure nitrogen environment, it was then heat-treated at 100°C for 20 minutes to form a 500 nm thick perovskite light-absorbing layer.

[0088] (5) Next, an electron transport layer (SnO2) with an average thickness of 10 nm is formed on top of the perovskite light-absorbing layer by atomic layer deposition (ALD).

[0089] (6) Next, a transparent electrode (ITO) with a thickness of 75 nm is formed on the top of the electron transport layer by sputtering.

[0090] (7) Finally, in 1×10 -7 Under pressure, silver (Ag) is deposited on top of the transparent electrode to form a metal electrode with a thickness of 100 nm, thereby fabricating a tandem silicon / perovskite heterojunction solar cell. In the tandem silicon / perovskite heterojunction solar cell, the silicon solar cell, transparent conductive layer, hole transport layer, intermediate layer, perovskite light absorption layer, electron transport layer, transparent electrode and metal electrode are laminated in sequence.

[0091] Comparative Example 2: Fabrication of Tandem Silicon / Perovskite Heterojunction Solar Cells

[0092] (1) Prepare silicon solar cells (180 μm thick) doped with n-type or p-type impurities, and remove SiO by hydrofluoric acid treatment. x An oxide film is formed, and residual hydrofluoric acid is removed using ultrapure water. A 20 nm thick transparent conductive layer (ITO) is then formed on top of the silicon solar cell after the oxide film has been removed using a sputtering process.

[0093] (2) Next, a 20 nm thick hole transport layer (NiO) is formed on top of the transparent conductive layer by a sputtering vacuum deposition process. x ).

[0094] (3) Next, 2PACz ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid) is spin-coated onto the top of the hole transport layer to form an intermediate layer with an average thickness of 3 nm.

[0095] (4) Next, a perovskite crystal structure (Cs) will be formed. 0.2 Fa 0.8 Pb(I) 0.8 Br 0.2 100 μl of the 1.3 M perovskite precursor solution was dropped onto the upper part of the intermediate layer. After spin-coating at 5000 rpm for 30 seconds in 99% pure nitrogen environment, it was then heat-treated at 100°C for 20 minutes to form a 500 nm thick perovskite light-absorbing layer.

[0096] (5) Next, an electron transport layer (SnO2) with an average thickness of 10 nm is formed on top of the perovskite light-absorbing layer by atomic layer deposition (ALD).

[0097] (6) Next, a transparent electrode (ITO) with a thickness of 75 nm is formed on the top of the electron transport layer by sputtering.

[0098] (7) Finally, in 1×10 -7 Under pressure, silver (Ag) is deposited on a transparent electrode with a thickness of 100 nm to form a metal electrode, thereby fabricating a tandem silicon / perovskite heterojunction solar cell. In the tandem silicon / perovskite heterojunction solar cell, the silicon solar cell, transparent conductive layer, hole transport layer, intermediate layer, perovskite light absorption layer, electron transport layer, transparent electrode and metal electrode are laminated in sequence.

[0099] Experimental Example 1: Measurement of Solar Cell Performance

[0100] For each of the tandem silicon / perovskite heterojunction solar cells fabricated in Examples 1 and 2 and Comparative Examples 1 and 2, the efficiency was measured using a solar simulation apparatus and a JV Keithley apparatus and using an initial JV curve, and the results are shown in Table 1 below.

[0101] [Table 1]

[0102]

[0103] As can be confirmed in Table 1, the tandem silicon / perovskite heterojunction solar cell fabricated in Example 1 exhibits improved power conversion efficiency with the improvement of open-circuit voltage.

[0104] Experimental Example 2: Analysis of the Surface Chemical Properties of the Hole Transport Layer

[0105] The surface chemical properties of the hole transport layer in each of the tandem silicon / perovskite heterojunction solar cells fabricated in Examples 1 and 2, and Comparative Examples 1 and 2, were analyzed by photoelectron spectroscopy (XPS). This method was used to measure the elemental composition, chemical and electronic states of the atoms in the materials.

[0106] Figure 1 This is a graph showing the intensity as a function of the binding energy. For example... Figure 1 As shown, compared with the tandem silicon / perovskite heterojunction solar cells fabricated in Comparative Example 1 and Comparative Example 2, Ni was confirmed on the surface of the hole transport layer of the tandem silicon / perovskite heterojunction solar cell fabricated in Example 1. 3+ Peak increase, O 3+ The peaks increased, which confirms the doping effect of cesium atoms.

[0107] Meanwhile, on the surface of the hole transport layer of the tandem silicon / perovskite heterojunction solar cell fabricated in Example 2, it was confirmed that the effect of doping was weakened due to the increase in defects of cesium atoms.

[0108] Experimental Example 3: Analysis of the surface chemical properties of tandem silicon / perovskite heterojunction solar cells

[0109] The surface chemical properties of the tandem silicon / perovskite heterojunction solar cells fabricated in Example 1 and Comparative Examples 1 and 2 were analyzed during the fabrication process using photoelectron spectroscopy (XPS). This method was used to measure the elemental composition, chemical and electronic states of the atoms in the materials.

[0110] Specifically, the surface chemical properties of the tandem silicon / perovskite heterojunction solar cells fabricated in Example 1 and Comparative Examples 1 and 2 were analyzed in the following states: first, when only the hole transport layer was fabricated (condition 1); second, when an intermediate layer was formed on the hole transport layer (condition 2); third, when a perovskite light-absorbing layer was formed on the intermediate layer (condition 3); and fourth, after the perovskite light-absorbing layer was formed, the perovskite light-absorbing layer was removed by using a solvent removal process (condition 4). The results are shown in Table 2 below. Figure 2 As shown.

[0111] [Table 2]

[0112]

[0113] The numerical values ​​for each of the nickel (Ni), oxygen (O), and cesium (Cs) elements listed in Table 2 represent the intensity of each element present on the upper surface. In other words, Ni under condition 2 represents the intensity of Ni observed at the surface of the hole transport layer / intermediate layer. Therefore, the reason for the decrease in Ni in the intermediate layer compared to Ni in the hole transport layer is that the elemental intensity of Ni decreases significantly as the intermediate layer forms on top of the hole transport layer.

[0114] Meanwhile, Table 2 confirms that when an intermediate layer is coated on top of the hole transport layer, the surface is primarily affected by the intermediate layer, and the work function and valence band peak value change due to the intermediate layer. However, in Example 1 with added Cs, it is confirmed that the work function and valence band peak value differ from those values ​​in Comparative Example 1 with the intermediate layer. Furthermore, Cs significantly increases on the surface of the intermediate layer, which is determined to be due to the interaction between the intermediate layer and Cs at the surface caused by the influence of Cs. In summary, unlike Comparative Examples 1 and 2, it can be determined that the work function and valence band peak value at the surface differ.

[0115] Furthermore, Cs decreases the most when the perovskite light-absorbing layer is removed, because the Cs intermediate layer is removed along with the perovskite light-absorbing layer.

[0116] The specific embodiments have been described and illustrated above. However, this invention is not limited to the embodiments described above, and those skilled in the art can make various modifications and implementations without departing from the spirit of the technical concept described in the appended claims.

Claims

1. A perovskite solar cell, comprising: A laminate in which a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated. An intermediate layer is formed between the hole transport layer and the perovskite light absorption layer, and The hole transport layer includes additives.

2. The perovskite solar cell of claim 1, wherein, The additives include one or more selected from alkali metals and alkaline earth metals.

3. The perovskite solar cell of claim 1, wherein, The hole transport layer comprises 1 mol% to 7 mol% of additives based on the total mol%.

4. The perovskite solar cell of claim 1, wherein, The intermediate layer comprises a self-assembled monolayer, which includes carbazole and phosphonic acid.

5. The perovskite solar cell according to claim 1, wherein, The hole transport layer and the intermediate layer have a thickness ratio of 1:0.05 to 1:0.

25.

6. The perovskite solar cell according to any one of claims 1 to 5, wherein, The perovskite solar cell is a pin-structured perovskite solar cell, a nip-inverted perovskite solar cell, a tandem perovskite solar cell, or a tandem silicon / perovskite heterojunction solar cell.

7. A method for manufacturing a perovskite solar cell, the method comprising: The first step is to form a hole transport layer on top of a transparent conductive layer using a solution process; The second step is to form an intermediate layer on top of the hole transport layer; as well as The third step is to form a perovskite light-absorbing layer on top of the intermediate layer. The hole transport layer includes additives.

8. The method according to claim 7, wherein, The additives include one or more selected from alkali metals and alkaline earth metals.

9. The method according to claim 7, wherein, The hole transport layer includes 1 mol% to 7 mol% of additives based on the total mol%.

10. The method according to claim 7, wherein, The intermediate layer comprises a self-assembled monolayer, which includes carbazole and phosphonic acid.

11. A series silicon / perovskite heterojunction solar cell, wherein the solar cell, a transparent conductive layer, a hole transport layer, an intermediate layer, a perovskite light-absorbing layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated. in, The hole transport layer includes additives.

12. The tandem silicon / perovskite heterojunction solar cell according to claim 11, wherein, The additives include one or more selected from alkali metals and alkaline earth metals, and The intermediate layer includes a self-assembled monolayer, which comprises carbazole and phosphonic acid.

13. The tandem silicon / perovskite heterojunction solar cell according to claim 11, wherein, The hole transport layer comprises 1 mol% to 7 mol% of additives based on the total mol%.

14. The tandem silicon / perovskite heterojunction solar cell according to claim 11, wherein, The solar cell is a polycrystalline silicon solar cell, a crystalline silicon solar cell, a perovskite solar cell, a gallium arsenide (GaAs) solar cell, a cadmium telluride (CdTe) solar cell, a CIGS (CuInGaSe) solar cell, a CZTS (Cu2ZnSnS4) solar cell, an organic solar cell, a fuel-sensitized solar cell, or a group 3 to 5 compound solar cell.

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