Interface passivation perovskite solar cell and preparation method thereof

Abstract

The invention discloses an interface passivation perovskite solar cell and a preparation method thereof, and relates to the technical field of perovskite cells. The interface passivation perovskite solar cell comprises a 2-ethyl-2-phenyl diethyl malonate passivation layer, and the structural formula of the 2-ethyl-2-phenyl diethyl malonate is shown as a formula (a): # imgabs 0 # formula (a). The charge transmission speed between the perovskite active layer and the interface of the interface passivated perovskite solar cell is high, and the cell stability is high.

Description

Technical Field

[0001] The present invention relates to the field of concrete, and in particular to an interface passivated perovskite solar cell and a preparation method thereof. Background Art

[0002] Organic halide perovskite solar cells have attracted widespread attention due to their excellent optoelectronic properties, such as adjustable band gap, high absorption coefficient, and ultra-high carrier mobility, which are very attractive in the photovoltaic field. Since pin-type perovskite solar cells can be prepared at low temperature and over a large area, they are a better choice for commercialization.

[0003] Perovskite solar cells have two key points at the four interfaces of hole transport layer / perovskite and perovskite / electron transport layer. Their interface contact has a great influence on the device. However, the interface treatment of current pin-type perovskite solar cells is poor, which affects the charge transfer speed and battery stability of the device. Summary of the invention

[0004] The present invention is made in view of the above-mentioned problems and provides an interface passivated perovskite solar cell and a preparation method thereof.

[0005] The first aspect of the present invention provides an interface passivated perovskite solar cell, wherein the interface passivated perovskite solar cell comprises a 2-ethyl-2-phenylmalonate passivation layer, wherein the structural formula of the 2-ethyl-2-phenylmalonate is as shown in formula (a):

[0006]

[0007] A second aspect of the present invention provides a method for preparing an interface passivated perovskite solar cell, comprising the following steps:

[0008] A flexible conductive substrate, a hole transport layer, a perovskite active layer, a 2-ethyl-2-phenylmalonate passivation layer, an electron transport layer and a metal electrode are sequentially arranged from bottom to top to obtain an interface passivated perovskite solar cell; wherein the arrangement of the 2-ethyl-2-phenylmalonate passivation layer comprises: slit coating a 2-ethyl-2-phenylmalonate solution on the perovskite active layer and then annealing.

[0009] In some embodiments of the present invention, the solvent of the diethyl 2-ethyl-2-phenylmalonate solution is one of anhydrous ethanol, ether, ethyl acetate, chlorobenzene, and isopropanol, and the solution concentration is 2 mg / mL to 14 mg / mL.

[0010] In some embodiments of the present invention, the hole transport layer is provided including slit coating a hole transport layer solution on the flexible conductive substrate and then annealing, and the solute of the hole transport layer solution includes one of CuI, CuSCN, NiOx, PTAA, PEDOT:PSS, and P3HT.

[0011] In some embodiments of the present invention, the concentration of the hole transport layer solution is 5 mg / mL to 15 mg / mL, and the thickness of the hole transport layer is 10 nm to 80 nm.

[0012] In some embodiments of the present invention, the setting of the perovskite active layer includes slit coating the perovskite precursor solution on the hole transport layer and then annealing, and the perovskite active layer is a perovskite film of APbX3 with a perovskite structure, wherein A is one or more of formamidinium ions, methylamine ions, cesium ions, and potassium ions, and X is Cl - Br - , I-one or more.

[0013] In some embodiments of the present invention, the concentration of the perovskite precursor solution is 0.1 mol / L to 1.5 mol / L, and the thickness of the perovskite active layer is 400 nm to 800 nm.

[0014] In some embodiments of the present invention, the electron transport layer is provided including slit coating an electron transport layer solution on the perovskite active layer and then annealing, and the solute of the electron transport layer solution includes any one of PC61BM, PC71BM, C60, C70 mixed with BCP.

[0015] In some embodiments of the present invention, the concentration of the electron transport layer solution is 10 mg / mL to 30 mg / mL, and the thickness of the electron transport layer is 20 nm to 80 nm.

[0016] In some embodiments of the present invention, the metal electrode is one of Au, Ag, and Al, and has a thickness of 70 nm to 100 nm.

[0017] The beneficial effects that can be achieved by the present invention are:

[0018] The present invention provides an interface passivated perovskite solar cell, wherein a passivation layer thin film is formed on an APbX3 perovskite thin film by using a 2-ethyl-2-phenylmalonate passivator, wherein the oxygen atom of the carbonyl group in the 2-ethyl-2-phenylmalonate passivator is reacted with the uncoordinated Pb 2+The interaction reduces the pinhole defects on the surface of the APbX3 perovskite active layer film and the recombination between carriers, increases the charge transfer speed between the perovskite active layer and the interface, reduces the tolerance of the external environment to the perovskite solar cell, and improves the stability of the perovskite solar cell. DETAILED DESCRIPTION

[0019] The following description is provided for those skilled in the art to fully understand the present invention, and is not intended to limit the subject matter described in the claims.

[0020] The "range" disclosed in the present invention is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present invention, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0021] If not otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution.

[0022] Unless otherwise specified, all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0023] If not otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0024] Organic halide perovskite solar cells have attracted widespread attention due to their excellent optoelectronic properties, such as adjustable band gap, high absorption coefficient, and ultra-high carrier mobility, which are very attractive in the photovoltaic field. Since pin-type perovskite solar cells can be prepared at low temperature and over a large area, they are a better choice for commercialization.

[0025] Perovskite solar cells have two key points at the four interfaces of hole transport layer / perovskite and perovskite / electron transport layer. Their interface contact has a great influence on the device. However, the interface treatment of current pin-type perovskite solar cells is poor, which affects the charge transfer speed and battery stability of the device.

[0026] In view of this, the present invention proposes an interface passivated perovskite solar cell, wherein the interface passivated perovskite solar cell comprises a 2-ethyl-2-phenylmalonate passivation layer, wherein the structural formula of the 2-ethyl-2-phenylmalonate is shown in formula (a):

[0027]

[0028] Diethyl 2-ethyl-2-phenylmalonate has a specific molecular structure. Its benzene ring, ester group and long chain provide good steric hindrance effect, which helps to form a protective layer on the surface of the perovskite film and provides good chemical stability and thermal stability. The carbonyl group (C=O) in diethyl 2-ethyl-2-phenylmalonate can react with the uncoordinated Pb in the perovskite. 2+ The formation of coordination bonds can slow down the crystallization rate of perovskite and adjust the crystallization quality of the film, thereby obtaining a perovskite film with low defect density and high crystallinity. In addition, diethyl 2-ethyl-2-phenylmalonate can effectively inhibit ion migration by bonding with halides.

[0029] In this scheme, the use of diethyl 2-ethyl-2-phenylmalonate for surface passivation in perovskite quantum dot films can improve the electronic coupling between quantum dots, increase carrier mobility, reduce defect state density, reduce carrier recombination, and improve charge transfer efficiency, thereby significantly improving the performance and stability of perovskite solar cells.

[0030] A second aspect of the present invention provides a method for preparing an interface passivated perovskite solar cell, comprising the following steps:

[0031] A flexible conductive substrate, a hole transport layer, a perovskite active layer, a 2-ethyl-2-phenylmalonate passivation layer, an electron transport layer and a metal electrode are sequentially arranged from bottom to top to obtain an interface passivated perovskite solar cell;

[0032] Wherein, the provision of the 2-ethyl-2-phenylmalonate passivation layer comprises: slit coating the 2-ethyl-2-phenylmalonate solution on the perovskite active layer and then annealing.

[0033] In some embodiments, the flexible conductive substrate includes ITO or FTO conductive glass, which serves as the anode layer of the battery and is responsible for collecting holes and forming the anode of the battery. In some embodiments, the preparation of the flexible conductive substrate includes ultrasonically cleaning the ITO flexible conductive substrate in acetone, anhydrous ethanol and deionized water for 30 minutes each, and then drying it with a nitrogen gun to obtain a clean flexible conductive substrate.

[0034] In some embodiments, the solvent of the 2-ethyl-2-phenylmalonate solution is one of anhydrous ethanol, ether, ethyl acetate, chlorobenzene, and isopropanol, and the solution concentration is 2 mg / mL to 14 mg / mL. Selecting a suitable solvent and concentration helps 2-ethyl-2-phenylmalonate to be more compatible with the perovskite layer, thereby more effectively passivating the surface defects of the perovskite material, reducing the recombination of carriers, and improving the photoelectric conversion efficiency of the battery. The 2-ethyl-2-phenylmalonate solution treated by slit coating and annealing can form a uniform passivation layer, reduce the decomposition of the perovskite material, and improve the long-term stability of the device.

[0035] In some embodiments, a 2-ethyl-2-phenylmalonate passivator is dissolved in any one of anhydrous ethanol, ether, ethyl acetate, chlorobenzene, and isopropanol to prepare a passivator solution with a concentration of 2-14 mg / mL. The passivator solution is slit coated on the perovskite film, the coating head moves at a speed of 10-20 mm / s, and the ink injection speed is 0.1-10 mm / s. After coating, annealing is performed at a temperature of 50-100° C. and an annealing time of 10-20 min. After annealing, a passivation layer, i.e., a 2-ethyl-2-phenylmalonate interface passivation layer, is obtained. All solvents used are analytically pure reagents.

[0036] In some embodiments, the hole transport layer is provided by slit coating a hole transport layer solution on the flexible conductive substrate and then annealing, wherein the solute of the hole transport layer solution includes one of CuI, CuSCN, NiOx, PTAA, PEDOT:PSS, and P3HT. The hole transport layer transports holes generated by the perovskite layer while preventing electrons from passing through to reduce the recombination of electrons and holes.

[0037] In some embodiments, a hole transport layer solution with a concentration of 5-15 mg / mL is coated on a clean flexible conductive substrate by slit coating, the coating head moves at a speed of 10-20 mm / s, and the ink injection speed is 0.1-10 mm / s; after coating, annealing is performed at a temperature of 100-200° C. and an annealing time of 15-20 min to obtain a hole transport layer.

[0038] In some embodiments, the concentration of the hole transport layer solution is 5 mg / mL to 15 mg / mL, and the thickness of the hole transport layer is 10 nm to 80 nm. The solvent used is a mixed solvent of any one or more of deionized water, anhydrous ethanol, chlorobenzene, isopropanol, acetonitrile, and anisole.

[0039] In some embodiments, the perovskite active layer is provided by slit coating a perovskite precursor solution on the hole transport layer and then annealing, wherein the perovskite active layer is a perovskite film of APbX3 with a perovskite structure, wherein A is one or more of formamidinium ions, methylamine ions, cesium ions, and potassium ions, and X is Cl-, Br - ,I - One or more of.

[0040] In some embodiments, the concentration of the perovskite precursor solution is 0.1 mol / L to 1.5 mol / L, and the thickness of the perovskite active layer is 400 nm to 800 nm.

[0041] In some embodiments, APbX3 is dissolved in a solvent in a molar ratio and stirred at room temperature to dissolve it completely to prepare a perovskite precursor solution with a concentration of 0.1-1.5 mol / L; wherein A is a formamidinium ion (FA + ), methylamine ion (MA + ), cesium ion (Cs + ), potassium ion (K + ), any one or more of which X is a chloride ion (Cl - ), bromide ion (Br - ), iodide ion (I -), wherein the solvent is one or more of DMF, DMSO, NMP, and γ-butyrolactone; slit coating the obtained perovskite precursor solution on the hole transport layer obtained in step 2, the coating head moving speed is 10-20 mm / s, and the ink injection speed is 0.1-10 mm / s; after coating, annealing treatment is performed, the annealing temperature is 100-200° C., and the annealing time is 10-20 min to obtain a perovskite active layer.

[0042] In some embodiments, the electron transport layer is provided by slit coating an electron transport layer solution on the perovskite active layer and then annealing, and the solute of the electron transport layer solution includes any one of PC61BM, PC71BM, C60, and C70 mixed with BCP.

[0043] The electron transport layer is responsible for transporting photogenerated electrons and preventing holes from passing through, forming a good ohmic contact with the perovskite layer. BCP is inserted between the electron transport layer and the cathode, which can significantly improve the electron collection rate at the interface, effectively reduce the accumulation of charge at the interface of the active layer, effectively restrain the movement of ions, and thus improve the conversion efficiency and stability of perovskite photovoltaic devices.

[0044] The incorporation of BCP can block the unwanted holes from the perovskite to the PCBM electron transport layer (ETL), thus suppressing the nonradiative electron-hole recombination.

[0045] In some embodiments, the introduction of the BCP layer can effectively anchor the uncoordinated Pb 2+ , and establish π-π stacking interactions with P3HT, reducing energy consumption, enhancing the structure of P3HT, and facilitating carrier transfer, thereby improving battery efficiency.

[0046] In some embodiments, the concentration of the electron transport layer solution is 10 mg / mL to 30 mg / mL, and the thickness of the electron transport layer is 20 nm to 80 nm. The electron transport material solution with a concentration of 10-30 mg / mL is directly slit coated on the 2-ethyl-2-phenylmalonic acid diethyl ester passivation layer, the coating head moving speed is 10-20 mm / s, the ink injection speed is 0.1-10 mm / s, and the electron transport layer is obtained after annealing at an annealing temperature of 100-200 ° C and an annealing time of 10-20 min. Among them, the electron transport material is a combination of any one of PC61BM, PC71BM, C60, and C70 and BCP, and the solvent used is a mixture of any one or more of anhydrous ethanol, anhydrous ether, chlorobenzene, isopropanol, anisole, and ethyl acetate.

[0047] In some embodiments, the metal electrode is one of Au, Ag, and Al, and has a thickness of 70 nm to 100 nm.

[0048] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention, and are not used to limit the present invention.

[0049] Example 1

[0050] Step 1: ultrasonically clean the ITO flexible conductive substrate in acetone, anhydrous ethanol, and deionized water for 30 minutes each, and blow dry with a nitrogen gun to obtain a clean ITO flexible conductive substrate.

[0051] Step 2: PEDOT:PSS was dispersed in deionized water to prepare a PEDOT:PSS solution with a concentration of 10 mg / mL, and then the solution was slit coated on the ITO flexible conductive substrate. The coating head moved at a speed of 15 mm / s and the ink injection speed was 0.6 mm / s. After coating, annealing was performed at a temperature of 120°C for 15 minutes to obtain a hole transport layer.

[0052] Step 3: Dissolve MAI and PbI2 in a mixed solution of DMF and DMSO in a volume ratio of 4:1 in a molar ratio of 1:1, stir to completely dissolve them, and obtain a 1.5 mol / L MAPbI3 perovskite precursor solution; slit-coat the prepared MAPbI3 perovskite precursor solution on the above-prepared hole transport layer, with a coating head moving speed of 15 mm / s and an ink injection speed of 0.6 mm / s. After coating, annealing is performed at a temperature of 120°C and an annealing time of 15 min to obtain a perovskite film.

[0053] Step 4: Dissolve diethyl 2-ethyl-2-phenylmalonate in anhydrous ethanol and stir to dissolve it completely to obtain a passivator solution with a concentration of 10 mg / mL. Slit-coat the passivator solution on the perovskite film. The coating head moves at a speed of 15 mm / s and the ink injection speed is 0.6 mm / s. After coating, annealing is performed at a temperature of 80°C and an annealing time of 15 minutes to obtain a passivation layer. The anhydrous ethanol is an analytically pure reagent.

[0054] Step 5: Slit-coat the electron transport layer solution with a concentration of 20 mg / mL onto the 2-ethyl-2-phenylmalonate passivation layer, the coating head moving speed is 15 mm / s, the ink injection speed is 0.6 mm / s, and annealing is performed after coating. The annealing temperature is 120°C and the annealing time is 15 min to obtain the electron transport layer; wherein the electron transport layer material is PC 61 It is composed of BM and BCP, and the solvent used is chlorobenzene.

[0055] Step 6: Evaporate a layer of Ag electrode on the electron transport layer prepared above to obtain a pin-type MAPbI3 perovskite solar cell.

[0056] Comparative Example 1

[0057] In Comparative Example 1, no passivation layer was prepared, and the rest was referred to Example 1.

[0058] Performance Test:

[0059] The electrical performance data of the interface passivated perovskite solar cells obtained in the examples and comparative examples were measured and the results were recorded:

[0060] Table 1: Test results of Example 1 and Comparative Example 1

[0061] <![CDATA[JSC(mA / cm 2 )]]> VOC(V) FF(%) PCE(%) Example 1 21.05 0.89 67.08 14.45 Comparative Example 1 21.60 0.95 71.04 16.55

[0062] As shown in Table 1, this scheme forms a passivation layer on the APbX3 perovskite film by using 2-ethyl-2-phenylmalonate passivator. The oxygen atom of the carbonyl group in the 2-ethyl-2-phenylmalonate passivator is bound to the uncoordinated Pb 2+ The interaction reduces the pinhole defects on the surface of the APbX3 perovskite active layer film and the recombination between carriers, increases the charge transfer speed between the perovskite active layer and the interface, reduces the tolerance of the external environment to the perovskite solar cell, and improves the stability of the perovskite solar cell.

[0063] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the main purpose of the present invention, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. An interface passivated perovskite solar cell, characterized in that: The interface passivated perovskite solar cell comprises a 2-ethyl-2-phenylmalonate passivation layer, and the structural formula of the 2-ethyl-2-phenylmalonate is shown in formula (a):

2. A method for preparing an interface passivated perovskite solar cell according to claim 1, characterized in that: The following steps are involved: A flexible conductive substrate, a hole transport layer, a perovskite active layer, a 2-ethyl-2-phenylmalonate passivation layer, an electron transport layer and a metal electrode are sequentially arranged from bottom to top to obtain an interface passivated perovskite solar cell; Wherein, the provision of the 2-ethyl-2-phenylmalonate passivation layer comprises: slit coating the 2-ethyl-2-phenylmalonate solution on the perovskite active layer and then annealing.

3. The method for preparing an interface passivated perovskite solar cell according to claim 2, characterized in that: The solvent of the diethyl 2-ethyl-2-phenylmalonate solution is one of anhydrous ethanol, ether, ethyl acetate, chlorobenzene and isopropanol, and the solution concentration is 2 mg / mL to 14 mg / mL.

4. The method for preparing an interface passivated perovskite solar cell according to claim 2, characterized in that: The hole transport layer is provided by slit coating a hole transport layer solution on the flexible conductive substrate and then annealing the solution. The solute of the hole transport layer solution includes one of CuI, CuSCN, NiOx, PTAA, PEDOT:PSS, and P3HT.

5. The method for preparing an interface passivated perovskite solar cell according to claim 4, characterized in that: The concentration of the hole transport layer solution is 5 mg / mL to 15 mg / mL, and the thickness of the hole transport layer is 10 nm to 80 nm.

6. The method for preparing an interface passivated perovskite solar cell according to claim 2, characterized in that: The perovskite active layer is provided by slit coating a perovskite precursor solution on the hole transport layer and then annealing. The perovskite active layer is a perovskite film of APbX3 with a perovskite structure, wherein A is one or more of formamidinium ions, methylamine ions, cesium ions, and potassium ions, and X is Cl - Br - ,I - One or more of.

7. The method for preparing an interface passivated perovskite solar cell according to claim 6, characterized in that: The concentration of the perovskite precursor solution is 0.1 mol / L to 1.5 mol / L, and the thickness of the perovskite active layer is 400 nm to 800 nm.

8. The method for preparing an interface passivated perovskite solar cell according to claim 2, characterized in that: The electron transport layer is provided by slit coating an electron transport layer solution on the perovskite active layer and then annealing the solution. The solute of the electron transport layer solution includes any one of PC61BM, PC71BM, C60, and C70 mixed with BCP.

9. The method for preparing an interface passivated perovskite solar cell according to claim 8, characterized in that: The concentration of the electron transport layer solution is 10 mg / mL to 30 mg / mL, and the thickness of the electron transport layer is 20 nm to 80 nm.

10. The method for preparing an interface passivated perovskite solar cell according to claim 2, characterized in that: The metal electrode is one of Au, Ag and Al, and has a thickness of 70nm to 100nm.

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