Perovskite solar cell, preparation method thereof and photovoltaic module

Abstract

The invention provides a perovskite solar cell, a preparation method thereof and a photovoltaic module. The perovskite solar cell comprises a first electrode, a hole transport layer, a perovskite layer, an electron transport layer and a second electrode which are stacked in sequence. The material of the hole transport layer comprises a biomolecular material which is fixed on a self-assembly monomolecular layer material through an intermolecular force, and the biomolecular material comprises one or more of guanine, adenine, thymine, uracil, cytosine, hydroxymethylcytosine, xanthine, hypoxanthine, 6-mercaptopurine and corrin. According to the perovskite cell provided by the invention, the biomolecular material with a plurality of nitrogen heterocyclic structures and amino groups is added to generate multipoint hydrogen-bond interaction and pi-pi accumulation with the tail end of the SAM, so that the orderliness of molecular arrangement is improved, and the dipole direction and strength of the whole interface are regulated and controlled; and a coordination bond or hydrogen bond network is formed by the coordination compound and uncoordinated cations or anions in perovskite, so that interface defects are effectively passivated, and the thermal stability and the humid and hot life of a device are enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a perovskite solar cell, a preparation method thereof and a photovoltaic module. BACKGROUND

[0002] Perovskite solar cells (PSCs) as a representative of a new generation of photovoltaic devices have made rapid progress in recent years due to their high light absorption coefficient, long carrier lifetime, low processing temperature and high power conversion efficiency, and their laboratory certified efficiency has broken through 26%. However, to realize the commercialization of perovskite cells, there are still many challenges, among which the interface engineering problem is considered as one of the key factors restricting the performance and stability of the device. At present, perovskite devices still face many challenges in practical application, especially the problems of interface instability, energy band mismatch and ion migration seriously affect the service life and large-area consistency of the device. Among them, the energy level mismatch and carrier recombination problem of perovskite interface is an important bottleneck restricting the efficiency improvement and stability.

[0003] In order to improve the interface performance, the traditional method is to modify the surface of the bottom electrode with self-assembled monolayers (SAMs) to adjust the work function, passivate interface defects and improve carrier selectivity. SAMs can guide the direction of dipole through its terminal polar group, thereby effectively changing the vacuum level position of the electrode surface, which helps to build an ideal energy band ladder and improve the open-circuit voltage (Voc) and fill factor (FF) of the device. However, this regulation method relies on the static dipole moment of SAMs molecules, and it is difficult to realize dynamic / multi-dimensional interface engineering functions (such as passivation defects, crystal regulation, stress adjustment), which cannot meet the dual needs of improving photoelectric performance and optimizing stability. SUMMARY

[0004] Therefore, it is necessary to provide a perovskite solar cell with good stability and photoelectric performance, a preparation method thereof and a photovoltaic module.

[0005] The present application provides a perovskite solar cell, which comprises a first electrode, a hole transport layer, a perovskite layer, an electron transport layer and a second electrode which are stacked in sequence.

[0006] The material of the hole transport layer comprises a biomolecule material and a biomolecule material fixed to a self-assembled monolayer material by intermolecular forces, and the biomolecule material comprises one or more of guanine, adenine, thymine, uracil, cytosine, hydroxymethyl cytosine, xanthine, hypoxanthine, 6-mercapto purine and corrin.

[0007] In one of the embodiments, the anchoring group in the self-assembled monolayer material comprises one or more of phosphonate, carboxylate, and silane.

[0008] In one of the embodiments, the self-assembled monolayer material comprises one or more of [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz), [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl]phosphonic acid (Me-2PACz), [4-(9H-carbazol-9-yl)butyl]phosphonic acid (4PACz), [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid (MeO-4PACz), [4-(7H-dibenzo[c,e][1,2]oxazin-7-yl)butyl]phosphonic acid (DBCz-4PACz), 4-fluorobenzoic acid (FBA), 3,4,5-trifluorobenzoic acid (TFBA), and 3-mercaptopropyltrimethoxysilane (MPTMS).

[0009] In one of the embodiments, the perovskite layer material comprises one or both of CsFAMAPbI3-based perovskite material and CsFAPbI3-based perovskite material.

[0010] In one of the embodiments, the first electrode is a transparent conductive electrode.

[0011] In one of the embodiments, the hole transport layer material comprises the self-assembled monolayer material and the biomolecule material in a molar ratio of (3 ~ 25):1.

[0012] The application also provides a preparation method of a perovskite solar cell, comprising the following steps:

[0013] providing a first electrode, coating a hole transport material solution on the surface of the first electrode, the hole transport material solution comprising a self-assembled monolayer material and a biomolecule material, annealing, and preparing a hole transport layer;

[0014] sequentially preparing a perovskite layer, an electron transport layer, and a second electrode on the surface of the hole transport layer;

[0015] In one of the embodiments, the biomolecule material comprises one or more of guanine, adenine, thymine, uracil, cytosine, hydroxymethyl cytosine, xanthine, hypoxanthine, 6-mercapto purine, and corrin.

[0016] In one of the embodiments, one or both of the following conditions is met:

[0017] (1) the annealing temperature is 80-120℃;

[0018] (2) the annealing time is 5-40 minutes

[0019] In one of the embodiments, the step of removing organic matters from the surface of the first electrode is included before coating the solution of the hole transport material on the surface of the first electrode.

[0020] In one of the embodiments, the method of removing organic matters includes one or both of ultraviolet ozone treatment and plasma treatment.

[0021] Further, the application also provides a photovoltaic module comprising the perovskite solar cell as described above or the perovskite solar cell prepared by the preparation method as described above.

[0022] In the perovskite battery provided by the application, the biomaterial with multiple nitrogen heterocyclic structures and amine groups can form multiple-point hydrogen bonding and π-π stacking with the tail end of SAM, so as to improve the order of molecular arrangement; the additional dipole coupling structure can be used to cooperatively control the direction and strength of the overall interface dipole; the coordination bond or hydrogen bond network can be formed with the uncoordinated cations or anions in the perovskite, so as to effectively passivate the interface defects; the thermal stability and hygrothermal life of the device can be enhanced by improving the interface bonding force and compatibility. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the specific embodiments of the application or the prior art, the drawings needed in the description of the specific embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Figure 1 The current-voltage curve comparison chart of the perovskite solar cells of Example 2 and Comparative Example 1 is shown, in which the horizontal coordinate is voltage and the vertical coordinate is current density.

[0025] Figure 2 The ultraviolet photoelectron spectroscopy measurement curve chart of the hole transport layer prepared in Example 2 is shown, in which the horizontal coordinate is binding energy and the vertical coordinate is intensity.

[0026] Figure 3 The ultraviolet photoelectron spectroscopy measurement curve chart of the hole transport layer prepared in Comparative Example 1 is shown, in which the horizontal coordinate is binding energy and the vertical coordinate is intensity.

[0027] Figure 4 The stability test comparison chart of the perovskite batteries after packaging of Example 2 and Comparative Example 1 is shown. DETAILED DESCRIPTION

[0028] For the purposes of the present application, a more complete understanding can be obtained by reference to the following description taken in connection with the accompanying drawings. The drawings are intended to illustrate preferred embodiments of the present application and are not intended to limit the scope of the present application. Rather, the drawings are intended to illustrate the disclosure of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the present application.

[0030] As used herein, the term "and / or", where used herein, is intended to include one or more of items listed, individually or in combination. For example, "A and / or B" includes A, B, and "a combination of A and B".

[0031] In the present document, "one or more" means any one of the listed items or any combination of the listed items, unless otherwise specified. Similarly, "one or more" and the like, where used in the context of "one or more of the other items", means the same, unless otherwise specified.

[0032] In the present document, "further", "furthermore", "in particular", "for example", "for instance", "such as", "for example", "for instance", and the like are used to describe different embodiments of the application and are not used to limit the scope of the present application. In the present document, A (such as B) means that B is a non-limiting example of A, unless otherwise specified. A can be understood as not limited to B.

[0033] In the present document, "optionally", "optional", and "optional" mean that the item can or can not be present, i.e. either of the two parallel schemes "yes" or "no" can be selected. If there are multiple "options" in a technical solution, each "option" is independent of the other, unless otherwise specified and there is no contradiction or mutual restriction. In the present application, "optionally contains", "optionally includes", and the like mean "contains or does not contain". "Optional component X" means that component X is present or absent, or that the component X is present or absent.

[0034] In the present document, the terms “first”, “second”, “third”, “fourth” and the like in the description and in the claims – are used for descriptive purposes only and not to be construed as indicating or implying relative importance or quantification of the indicated technical features. Furthermore, the terms “first”, “second”, “third”, “fourth” and the like are used only for non-exhaustive, descriptive purposes and should not be construed as implying a limitation of the scope of the technical features indicated.

[0035] In the present document, the technical features described in an open-ended manner include both the closed technical solution consisting of the listed features and the open technical solution comprising the listed features.

[0036] In the present document, in relation to numerical intervals (i.e. numerical ranges), unless otherwise specified, the distribution of the selectable values within the numerical interval is considered to be continuous and includes both numerical end points of the numerical interval (i.e. the minimum and maximum values) and every numerical value between the two numerical end points. Unless otherwise specified, when a numerical interval refers only to integers within the numerical interval, the inclusion of both end point integers and every integer between the two end points is equivalent to the direct listing of each integer. When multiple numerical ranges are provided to describe a feature or a characteristic, these numerical ranges can be combined. In other words, unless otherwise indicated, the numerical ranges disclosed herein are to be understood as including any and all sub-ranges within the numerical ranges. The “numerical values” in the numerical intervals can be any quantitative values such as numbers, percentages, ratios, etc. The “numerical intervals” are intended to broadly include numerical interval types such as percentage intervals, ratio intervals, value intervals, etc.

[0037] The present application provides a perovskite solar cell, comprising a first electrode, a hole transport layer, a perovskite layer, an electron transport layer and a second electrode which are sequentially stacked;

[0038] The material of the hole transport layer includes biomolecular material and biomolecular material fixed to self-assembled monolayer material by intermolecular force, and the biomolecular material includes one or more of guanine, adenine, thymine, uracil, cytosine, hydroxymethyl cytosine, xanthine, hypoxanthine, 6-mercapto purine and corrin.

[0039] In the perovskite battery provided by the present application, by adding biomolecular material with multiple nitrogen heterocyclic structures and amine groups, multiple-point hydrogen bonding and π-π stacking with the tail end of SAM can be achieved, the order of molecular arrangement is improved, additional dipole coupling structures are provided to cooperatively control the direction and strength of the overall interface dipole, coordination bonds or hydrogen bond networks are formed with uncoordinated cations or anions in perovskite, effectively passivating interface defects, and the thermal stability and humid heat life of the device are enhanced by improving the interface bonding force and compatibility.

[0040] In some specific examples, the anchoring group in the self-assembled monolayer material includes one or more of phosphonate, carboxylate, and silane. The self-assembled monolayer material includes anchoring groups to immobilize molecules to the substrate through chemical bonding or strong interactions, determines the adhesion stability; the linking groups regulate the order of molecular arrangement and the basic properties; the terminal functional groups endow specific application functions. The anchoring group is first combined with the substrate to form an initial adsorption layer, and the linking group drives the ordered arrangement of molecules through intermolecular forces (such as van der Waals force, π-π stacking).

[0041] In some specific examples, the self-assembled monolayer material includes one or more of [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz), [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl]phosphonic acid (Me-2PACz), [4-(9H-carbazol-9-yl)butyl]phosphonic acid (4PACz), [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid (MeO-4PACz), [4-(7H-dibenzo[c,e][1,2]oxazin-7-yl)butyl]phosphonic acid (DBCz-4PACz), 4-fluorobenzoic acid (FBA), 3,4,5-trifluorobenzoic acid (TFBA), and 3-mercaptopropyltrimethoxysilane (MPTMS).

[0042] In some specific examples, the material of the hole transport layer includes a self-assembled monolayer material and a biomolecular material in a molar ratio of (3 ~ 25):1. Specifically, the molar ratio of the material of the hole transport layer in the material of the hole transport layer can be, but is not limited to, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, or 25:1.

[0043] In some specific examples, the first electrode is a transparent conductive electrode. The material of the transparent conductive electrode includes one or more of fluorine tin oxide transparent conductive glass (FTO), indium tin oxide transparent conductive glass (ITO), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). Further, the material of the transparent conductive electrode includes fluorine tin oxide transparent conductive glass (FTO), indium tin oxide transparent conductive glass (ITO), indium tin oxide transparent conductive glass (ITO) / polyethylene terephthalate (PET), or indium tin oxide transparent conductive glass (ITO) / polyethylene naphthalate (PEN).

[0044] Further, the material of the perovskite layer is ABX3, wherein A is one or more of formamidinium cation, methylammonium cation and cesium ion; X is one or more of fluoride ion, chloride ion, bromide ion and iodide ion; B is lead ion or tin ion. In some specific examples, the material of the perovskite layer includes one or both of CsFAMAPbI3-based perovskite material and CsFAPbI3-based perovskite material. In some specific examples, a passivation layer is further provided between the perovskite layer and the electron transport layer. The material of the passivation layer includes one or more of piperazine dihydroiodide (PDI), ethylenediamine diiodide (EDAI2) and phenethylamine iodide (PEAI).

[0045] In some specific examples, the perovskite solar cell further includes a buffer layer provided between the electron transport layer and the second electrode, and the material of the buffer layer includes one or more of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and tin dioxide (SnO2).

[0046] Further, the material of the electron transport layer includes one or more of carbon 60 (C60), [6,6]-phenyl C61 butyric acid methyl ester and zinc oxide.

[0047] In some specific examples, the material of the second electrode includes one or more of silver, copper, gold and carbon.

[0048] The present application also provides a method for preparing a perovskite solar cell, including the following steps:

[0049] providing a first electrode, coating a hole transport material solution on the surface of the first electrode, the hole transport material solution including a self-assembled monolayer material and a biomolecule material, annealing to prepare a hole transport layer;

[0050] sequentially preparing a perovskite layer, an electron transport layer and a second electrode on the surface of the hole transport layer;

[0051] wherein the biomolecule material includes one or more of guanine, adenine, thymine, uracil, cytosine, hydroxymethyl cytosine, xanthine, hypoxanthine, 6-mercapto purine and corrin.

[0052] In some specific examples, the step of coating the hole transport material solution on the surface of the first electrode includes a step of performing ultraviolet ozone treatment or plasma treatment on the surface of the first electrode before coating the hole transport material solution on the surface of the first electrode. It can be understood that ultrasonic cleaning is further included before performing the ultraviolet ozone treatment, which can effectively remove surface organic residues and improve the surface hydrophilicity and the assembly efficiency of the hole transport material SAM.

[0053] In some specific examples, the temperature of annealing is 80℃-120℃. Specifically, the temperature of annealing can be, but is not limited to, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃ or 120℃.

[0054] In some specific examples, the time of annealing is 5 minutes-40 minutes. Specifically, the time of annealing can be, but is not limited to, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes or 40 minutes. Annealing can promote the fixation of adsorbed molecules and drive out solvent residues.

[0055] In some specific examples, the solvent of the hole transport material solution comprises one or more of methanol, ethanol, isopropanol and N,N-dimethylformamide (DMF).

[0056] Further, the present application also provides a photovoltaic module comprising the perovskite solar cell as described above or the perovskite solar cell prepared by the preparation method as described above.

[0057] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and are not used to limit the scope of the present application. The experimental methods in the following examples, if not otherwise specified, are preferred to refer to the guidance given in the present application, and can also be in accordance with the experimental manual or conventional conditions in the art, or in accordance with the conditions suggested by the manufacturer, or in accordance with the known experimental methods in the art.

[0058] In the following specific examples, the measurement parameters of raw material components may, if not otherwise specified, have slight deviations within the weighing accuracy range. The temperature and time parameters allow for acceptable deviations caused by the instrument testing accuracy or operation accuracy. "Normal temperature" refers to 25℃; "normal pressure" refers to 100KPa or 101KPa.

[0059] The technical features of the above examples can be combined in any manner. In order to make the description concise, not all possible combinations of the technical features in the above examples are described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0060] Example 1

[0061] Step one, substrate pretreatment

[0062] The commercial ITO conductive glass was sequentially cleaned in deionized water, anhydrous ethanol, acetone and isopropanol for 10 minutes each time. After washing, it was dried with nitrogen and irradiated for 15 minutes using a UV ozone treatment device to completely remove surface organic residues and improve the surface hydrophilicity and SAM assembly efficiency.

[0063] Step two, SAM layer deposition

[0064] MeO-2PACz (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid) was dissolved in anhydrous methanol with a concentration of 0.8 mg / mL as a phosphonic acid anchoring type self-assembly precursor, and 0.1 μmol guanine powder was added to 1 mL of SAM solution. The prepared SAM / guanine blended solution was dropped onto the treated ITO surface, and an ultrathin self-assembled composite molecular layer was formed by spin coating (2800 rpm for 40 s). After spin coating, the sample was annealed on a 100 °C hot stage for 8 minutes to promote the fixation of adsorbed molecules and drive out solvent residues.

[0065] Step three, perovskite layer deposition

[0066] Cs 0.05 MA 0.10 FA 0.85 PbI3 as perovskite composition configuration, with a concentration of 1.6 M, using DMF:DMSO = 4:1 as the solvent system, and adding 10 mol% MACl to promote perovskite film morphology optimization. The solution was stirred at room temperature for 4 hours and filtered through a 0.22 μm polytetrafluoroethylene filter. Then the perovskite precursor solution was spin-coated on the above-mentioned treated SAM layer. The deposition method was two-stage spin coating: first stage: 2000 rpm for 10 seconds, second stage: 5000 rpm for 40 seconds. At the last 15 seconds (i.e. 35 seconds) of spin coating, 160 μL of chlorobenzene (CB) was quickly added as an anti-solvent to induce instantaneous crystallization, forming a smooth and dense precursor film. Immediately after spin coating, it was transferred to a 100 °C hot stage for annealing for 30 minutes to achieve complete crystallization of the perovskite layer and solvent removal.

[0067] Step four, interface passivation layer deposition

[0068] A solution of piperazine dihydroiodide (PDI, 0.2 mg / mL) in isopropanol was dropped onto the surface of the perovskite film cooled to room temperature, and spin-coated at 5000 rpm for 30 seconds to form an extremely thin interface passivation layer to further passivate the perovskite surface vacancies and trap states, followed by annealing on an 80 °C hot stage for 10 minutes.

[0069] Step five, electron transport layer, buffer layer and metal electrode deposition

[0070] In a vacuum chamber (working pressure 5×10 -4 Pa), the following structure was deposited in sequence using the hot evaporation method:

[0071] C60 layer: evaporation rate 0.3 Å / s, thickness controlled at 25 nm;

[0072] Bathocuproin (BCP) layer: evaporation rate 0.8 Å / s, thickness 8 nm, as a buffer layer to adjust the energy level buffer between C60 and Ag;

[0073] Ag electrode: evaporation rate 1 Å / s, total thickness 100 nm.

[0074] Example 2

[0075] The preparation method of the perovskite solar cell in Example 2 is basically the same as that in Example 1, and the only difference is that in step two, 0.1 μmol guanine is replaced by 0.3 μmol.

[0076] Example 3

[0077] The preparation method of the perovskite solar cell in Example 2 is basically the same as that in Example 1, and the only difference is that in step two, 0.1 μmol guanine is replaced by 0.5 μmol.

[0078] Example 4

[0079] Step one, substrate pretreatment

[0080] The commercial ITO conductive glass is sequentially ultrasonically cleaned in deionized water, anhydrous ethanol, acetone and isopropanol, each for 10 minutes. After washing, dry it with nitrogen and irradiate it for 15 minutes using a UV ozone treatment device to completely remove surface organic residues and improve surface hydrophilicity and SAM assembly efficiency.

[0081] Step two, SAM layer deposition

[0082] Dissolve MeO-2PACz (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid) in anhydrous methanol, control the concentration to be 0.8 mg / mL, as a phosphonic acid anchor type self-assembled precursor, and add 0.3 μmol of adenine powder to 1 mL of SAM solution. Drop the above prepared SAM / adenine blended solution on the treated ITO surface, and form an ultrathin self-assembled composite molecular layer by spin coating (2800 rpm, for 40 s). After spin coating, the sample is annealed on a 100°C hot stage for 8 minutes to promote the fixation of the adsorbed molecules and drive out the solvent residues.

[0083] Step three, perovskite layer deposition

[0084] Cs 0.05 MA 0.10 FA 0.85PbI3 is a perovskite composition with a concentration of 1.6 M, using DMF:DMSO = 4:1 as the solvent system, with the addition of 10 mol% MACI to promote perovskite film morphology optimization. The solution was stirred at room temperature for 4 hours and filtered through a 0.22 μm polytetrafluoroethylene filter membrane. Then the perovskite precursor solution was spin-coated on the above-mentioned treated SAM layer. The deposition method was two-stage spin coating: the first stage was 2000 rpm for 10 seconds, and the second stage was 5000 rpm for 40 seconds. At the last 15 seconds of spin coating (i.e. the 35th second), 160 μL of chlorobenzene (CB) was quickly added as an anti-solvent to induce instantaneous crystallization, forming a smooth and dense precursor film. After spin coating, it was immediately transferred to a 100°C hot stage for annealing for 30 minutes to achieve complete crystallization of the perovskite layer and solvent removal.

[0085] Step four, interfacial passivation layer deposition

[0086] A solution of piperazine dihydroiodide (PDI, 0.2 mg / mL) in isopropanol was dropped onto the surface of the perovskite film cooled to room temperature, and spin-coated at 5000 rpm for 30 seconds to form an extremely thin interfacial passivation layer to further passivate the perovskite surface vacancies and trap states, followed by annealing on a 80°C hot stage for 10 minutes.

[0087] Step five, electron transport layer, buffer layer and metal electrode deposition

[0088] In a vacuum chamber (working pressure 5x10 -4 Pa), the following structure was deposited in turn using the thermal evaporation method:

[0089] C60 layer: evaporation rate 0.3 Å / s, thickness controlled to 25 nm;

[0090] Bathocuproin (BCP) layer: evaporation rate 0.8 Å / s, thickness 8 nm, as a buffer layer to adjust the energy level buffer between C60 and Ag;

[0091] Ag electrode: evaporation rate 1 Å / s, total thickness 100 nm.

[0092] Comparative Example 1

[0093] Step one, substrate pretreatment

[0094] Commercial ITO conductive glass was sequentially ultrasonically cleaned in deionized water, anhydrous ethanol, acetone and isopropanol, each step lasting 10 minutes. After washing, it was blown dry with nitrogen and irradiated for 15 minutes using a UV ozone treatment device to completely remove surface organic residues and improve surface hydrophilicity and SAM assembly efficiency.

[0095] Step two, SAM layer deposition

[0096] MeO-2PACz (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid) was dissolved in anhydrous methanol with a concentration of 0.8 mg / mL as the phosphonic acid anchoring type self-assembly precursor. The prepared SAM solution was dropped onto the treated ITO surface by spin-coating (2800 rpm for 40 s). After spin-coating, the sample was annealed on a hot stage at 100 °C for 8 minutes to promote the fixation of the adsorbed molecules and remove the solvent residues.

[0097] Step three, perovskite layer deposition

[0098] Cs 0.05 MA 0.10 FA 0.85 PbI3 was used as the perovskite composition with a concentration of 1.6 M in a solvent system of DMF:DMSO = 4:1, with the addition of 10 mol% MACl to promote the morphology optimization of the perovskite film. The solution was stirred at room temperature for 4 hours and filtered through a 0.22 μm polytetrafluoroethylene filter membrane. Then the perovskite precursor solution was spin-coated on the above-mentioned treated SAM layer. The deposition method was two-stage spin-coating: the first stage was 2000 rpm for 10 seconds, and the second stage was 5000 rpm for 40 seconds. At the last 15 seconds (i.e., the 35th second) of spin-coating, 160 μL of chlorobenzene (CB) was quickly added as an anti-solvent to induce instantaneous crystallization, forming a smooth and dense precursor film. After spin-coating, the sample was immediately transferred to a hot stage at 100 °C for annealing for 30 minutes to achieve complete crystallization of the perovskite layer and solvent removal.

[0099] Step four, interface passivation layer deposition

[0100] A solution of piperazine dihydroiodide (PDI, 0.2 mg / mL) in isopropanol was dropped onto the surface of the perovskite film cooled to room temperature, and spin-coated at 5000 rpm for 30 seconds to form an extremely thin interface passivation layer to further passivate the surface vacancies and trap states of the perovskite, followed by annealing on a hot stage at 80 °C for 10 minutes.

[0101] Step five, electron transport layer, buffer layer and metal electrode deposition

[0102] In a vacuum chamber (working pressure 5×10 -4 Pa), the following structure was deposited in sequence using the thermal evaporation method:

[0103] C60 layer: evaporation rate 0.3 Å / s, thickness controlled at 25 nm;

[0104] Bathocuproin (BCP) layer: evaporation rate 0.8 Å / s, thickness 8 nm, as a buffer layer to adjust the energy level buffer between C60 and Ag;

[0105] Ag electrode: evaporation rate 1 Å / s, total thickness 100 nm.

[0106] Comparative Example 2

[0107] Step one, substrate pretreatment

[0108] Commercial ITO conductive glass was sequentially cleaned in deionized water, anhydrous ethanol, acetone and isopropanol for 10 minutes each. After washing, it was dried with nitrogen and irradiated for 15 minutes using a UV ozone treatment device to completely remove surface organic residues and improve surface hydrophilicity and SAM assembly efficiency.

[0109] Step two, SAM layer deposition

[0110] MeO-2PACz (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid) was dissolved in anhydrous methanol, with a concentration of 0.8 mg / mL. The prepared SAM solution was added dropwise to the treated ITO surface, and spin coating was used (2800 rpm for 40 s). After spin coating, the sample was annealed on a 100°C hot stage for 8 minutes to promote the fixation of adsorbed molecules and remove solvent residues.

[0111] Step three, perovskite layer deposition

[0112] Cs 0.05 MA 0.10 FA 0.85 PbI3 was configured as the perovskite composition, with a concentration of 1.6 M, using DMF:DMSO = 4:1 as the solvent system, adding 10 mol% MACl to promote perovskite film morphology optimization, and adding 0.3 μmol guanine powder to 1 mL of perovskite solution. The solution was stirred at room temperature for 4 hours and filtered through a 0.22 μm polytetrafluoroethylene filter. The perovskite precursor solution was then spin-coated on the above-mentioned treated SAM layer. The deposition method was two-stage spin coating: first stage: 2000 rpm for 10 seconds, second stage: 5000 rpm for 40 seconds. At the last 15 seconds of spin coating (i.e. 35 seconds), 160 μL of chlorobenzene (CB) was quickly added as an anti-solvent to induce instantaneous crystallization, forming a smooth and dense precursor film. After spin coating, it was immediately transferred to a 100°C hot stage for annealing for 30 minutes to achieve complete crystallization of the perovskite layer and solvent removal.

[0113] Step four, interface passivation layer deposition

[0114] A thin layer of interfacial passivation layer was formed on the perovskite film surface by dropping piperazine dihydroiodide (PDI, 0.2 mg / mL) in isopropanol solution at room temperature, spin-coating at 5000 rpm for 30 seconds, to further passivate the surface vacancies and trap states of perovskite, followed by annealing on a hot plate at 80°C for 10 minutes.

[0115] Step five, deposition of electron transport layer, buffer layer and metal electrode

[0116] In a vacuum chamber (working pressure 5x10 -4 Pa), the following structure was sequentially deposited by using the thermal evaporation method:

[0117] C60 layer: evaporation rate 0.3 Å / s, thickness control 25 nm;

[0118] Bathocuproin (BCP) layer: evaporation rate 0.8 Å / s, thickness 8 nm, as a buffer layer, used to adjust the energy level buffer between C60 and Ag;

[0119] Ag electrode: evaporation rate 1 Å / s, total thickness 100 nm.

[0120] Device performance test

[0121] The prepared device was tested for J-V under AM1.5G standard solar light simulator, with a scanning rate of 10 mV / s. The ultraviolet photoelectron spectrometer (UPS) measurement was carried out on a STARPES (SPECS) system with a He I (21.22 eV) ultraviolet light source, and the work function of the substrate / SAM sample was measured and analyzed. The stability test was carried out by continuously testing the maximum power point (MPP) of the encapsulated perovskite solar cell under 1 sun equivalent light intensity in an atmosphere with a relative humidity of 70-80%. The devices obtained in the above examples and comparative examples were tested for J-V under calibrated AM1.5G standard solar light simulator, with a starting voltage of 1.2V, a cutoff voltage of -0.1V, and a scanning rate of 10 mV / s. The test parameters included open circuit voltage (Voc), short circuit current (Jsc), fill factor (FF) and photoelectric conversion efficiency (PCE), and the test results are shown in Table 1:

[0122] Table 1

[0123]

[0124] Comparative Example 1 is a device without the addition of guanine, and the efficiency is only 23.35%, and Voc, Jsc and FF are all relatively low. After the addition of guanine in Example 1, it can be seen that Voc, Jsc and FF have all been improved, and the efficiency reaches 24.18%. This is attributed to the fact that the introduction of guanine into SAM can induce the ordered arrangement of SAM, improve the orientation consistency of SAM layer, because guanine has strong π-π stacking ability, can occur π-π face-to-face stacking with the carbazole backbone of MeO-2PACz, and the carbonyl group of guanine can occur hydrogen bonding with the amine group of the adjacent MeO-2PACz tail, thereby enhancing the consistency of SAM dipole direction, improving the SAM work function regulation ability, making the substrate work function closer to the valence band top of perovskite. It can be seen from the adjustment of different proportions of guanine and SAM in Examples 1-3 that the efficiency of Example 2 (0.3 μmol guanine) is the best, reaching 25.03%. The numerical value of the substrate work function adjusted by different concentrations of guanine is also different, thereby reflecting the difference in device efficiency. Under the concentration of 0.3 μmol guanine, the substrate work function is closer to the valence band top of perovskite, and the hole extraction ability is further improved, and the energy barrier is further reduced, thereby improving the efficiency. In addition, guanine itself has carbonyl, amine and N heterocyclic groups that can coordinate with uncoordinated Pb 2+ , FA + , etc. on the surface of perovskite, further reducing the interface trap state density and improving Voc. Example 4 is a device after introducing adenine into the SAM solution. The structure of adenine also has amine groups and multiple nitrogen heteroaromatic sites, and the overall polarity is moderately symmetrical. Its blending with MeO-2PACz mainly depends on π-π stacking and a small amount of hydrogen bonding, and can also assist the SAM layer to form a more vertical and ordered arrangement, thereby improving the consistency of the dipole direction and the interface flatness. However, the interface passivation effect is limited, especially in terms of treating uncoordinated metal or halogen ions on the surface of perovskite, and its binding force is not as good as that of molecules containing carbonyl groups. In contrast, guanine, in addition to having the same purine skeleton as adenine, also contains a strongly polar carbonyl group, which makes it have stronger affinity and chemical passivation ability in forming hydrogen bond networks and coordinating with defect ions such as Pb 2+ , etc. on the surface of perovskite. When guanine is blended in MeO-2PACz, not only can it be arranged cooperatively with the main chain of MeO-2PACz through π-π stacking, but its carbonyl and amino groups can also form a stable multi-point hydrogen bond network with adjacent molecules or perovskite crystal surfaces, thereby improving the interface density and dipole sequence. This effect makes guanine generally better than adenine in terms of improving work function, enhancing open-circuit voltage (Voc), and reducing non-radiative recombination loss. Details of the J-V curve are shown in Figure 1Comparative Example 2 is a method of adding biomolecular material into the perovskite solution, taking the optimal 0.3 μmol concentration of guanine and adding it into the perovskite solution, and comparing it with Comparative Example 1 in terms of J-V, the improvement is not obvious, the main reason being that the guanine molecules themselves are not fixed by face-to-face stacking and hydrogen bonding with SAM, the substrate work function is not adjusted, and only part of the carbonyl and amine groups in guanine coordinate with part of the Pb 2+ defect ions in perovskite, so that the open voltage is only slightly improved, and the efficiency is only 23.79%, while the efficiency of guanine added to the SAM solution at the same concentration can reach 25.03%.

[0125] Taking the optimal ITO substrate on which SAM is prepared in Example 2 and Comparative Example 1, ultraviolet photoelectron spectroscopy (UPS measurement) is performed, as shown in Figure 2 and Figure 3 It can be seen that the secondary electron cutoff region of the ITO / MeO-2PACz substrate of the comparative example is 16.59 eV, and the calculated work function is 4.63 eV, while the secondary electron cutoff region of the ITO / MeO-2PACz+guanine substrate in Example 2 is 16.27 eV, and the calculated work function is 4.95 eV. The carbonyl and amine groups of guanine can be fixed by hydrogen bonding with adjacent MeO-2PACz tail ends, thereby enhancing the consistency of the SAM dipole direction, so that Example 2 exhibits a larger surface work function, thereby significantly improving the hole extraction efficiency.

[0126] The optimal cells of Example 2 and Comparative Example 1 are encapsulated, and the maximum power point (MPP) of the encapsulated perovskite solar cells is tested under a relative humidity of 70-80% in an atmospheric environment for 1 sun equivalent light intensity. The test results are as shown in Figure 4 , compared with the initial efficiency, the efficiency of Example 2 decreases to 94.52% after 2000h, but the efficiency of Comparative Example 1 decreases to 76.19% after 700h. The SAM without guanine added in Comparative Example 1 is arranged unevenly, which is easy to produce uneven electric field between ITO and perovskite, form local band bending, cause charge accumulation, stress accumulation and perovskite structure distortion. The addition of guanine in Example 2 can form a stable hydrogen bond network and π-π stacking structure, making the SAM interface layer more dense and ordered, thereby effectively passivating the surface defects of perovskite, inhibiting the intrusion of ions and water and oxygen, relieving the interface electric field and stress accumulation, improving the interface energy level matching and chemical stability, and finally significantly enhancing the long-term running stability of perovskite solar cells under multiple stress conditions.

[0127] In this document, where a method comprising multiple steps is described, unless specifically stated otherwise, the order of the steps is not strictly limited to the order described, and the steps can be performed in any order. Also, any step can comprise multiple sub-steps or stages, which do not necessarily have to be performed at the same time, but can be performed at different times, and the order of the sub-steps or stages does not necessarily have to be sequential, but can be performed in rotation or alternation or simultaneously with other steps or sub-steps or stages of other steps.

[0128] Any combination of the technical features of the above embodiments can be made, and for brevity, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combination of the technical features does not contradict, it shall be considered within the scope of the present disclosure.

[0129] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it shall not be understood as a limitation on the scope of the patent right of the present application. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent right of the present application shall be subject to the appended claims, and the description and the drawings can be used to explain the scope of the claims.

Claims

1. A perovskite solar cell, characterized in that, It includes a first electrode, a hole transport layer, a perovskite layer, an electron transport layer, and a second electrode stacked in sequence; The hole transport layer material includes self-assembled monolayer materials and biomolecular materials fixed to the self-assembled monolayer materials by intermolecular forces. The biomolecular materials include one or more of guanine, adenine, thymine, uracil, cytosine, hydroxymethylcytosine, xanthine, hypoxanthine, 6-mercaptopurine, and gurnorline.

2. The perovskite solar cell as described in claim 1, characterized in that, The anchoring groups in the self-assembled monolayer material include one or more of phosphonates, carboxylates, and silanes.

3. The perovskite solar cell as described in claim 1 or 2, characterized in that, The self-assembled monolayer material includes one or more of the following: [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid, [4-(9H-carbazole-9-yl)butyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid, [4-(7H-dibenzocarbazole-7-yl)butyl]phosphonic acid, 4-fluorobenzoic acid, 3,4,5-trifluorobenzoic acid, and 3-mercaptopropyltrimethoxysilane.

4. The perovskite solar cell according to claim 1 or 2, characterized in that, The material of the perovskite layer includes one or both of CsFAMAPbI3-based perovskite materials and CsFAPbI3-based perovskite materials.

5. The perovskite solar cell according to claim 1 or 2, characterized in that, The hole transport layer comprises the self-assembled monolayer material in a molar ratio of (3 ~ 25):1 and the biomolecular material.

6. The perovskite solar cell according to claim 1 or 2, characterized in that, The first electrode is a transparent conductive electrode.

7. A method for fabricating a perovskite solar cell, characterized in that, Includes the following steps: A first electrode is provided, and a hole transport material solution is coated on the surface of the first electrode. The hole transport material solution includes a self-assembled monolayer material and a biomolecular material. Annealing is performed to prepare a hole transport layer. A perovskite layer, an electron transport layer, and a second electrode are sequentially fabricated on the surface of the hole transport layer. The biomolecular materials include one or more of guanine, adenine, thymine, uracil, cytosine, hydroxymethylcytosine, xanthine, hypoxanthine, 6-mercaptopurine, and gorolin.

8. The method for preparing a perovskite solar cell as described in claim 7, characterized in that, The annealing temperature is 80℃~120℃.

9. The method for preparing a perovskite solar cell as described in claim 7, characterized in that, Annealing time is 5 to 40 minutes.

10. A photovoltaic module, characterized in that, This includes perovskite solar cells as described in any one of claims 1 to 6 or perovskite solar cells prepared by the preparation method described in any one of claims 7 to 9.

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