Perovskite solar cell based on composite hole transport layer and preparation method thereof

Abstract

The invention discloses a perovskite solar cell based on a composite hole transport layer and a preparation method thereof, and belongs to the technical field of perovskite solar cells. The perovskite solar cell based on the composite hole transport layer comprises an ITO substrate, the composite hole transport layer, a perovskite light absorption layer, an electron transport layer and a metal electrode layer which are stacked in sequence. The preparation materials of the composite hole transport layer comprise heteropolyacid salt and a small molecular hole material; the mass ratio of the heteropolyacid salt to the small molecular hole material is (0.5-1.5): 1. The heteropolyacid salt and the small molecule hole material are utilized to form the composite hole transport layer, the extraction process and the transport process of hole carriers are effectively improved, non-radiative recombination in the carrier transport process is reduced, the photoelectric conversion performance of the device is improved, and in addition, the thermal stability of the device is greatly improved due to the good thermal stability of the heteropolyacid salt.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite solar cells, and more specifically relates to a perovskite solar cell based on a composite hole transport layer and a preparation method thereof. Background Art

[0002] Perovskite solar cells have been widely studied in recent years due to their simple preparation process and high photoelectric conversion efficiency, bringing new opportunities to the photovoltaic field. At present, there is still a big gap between their photoelectric conversion efficiency and the Shockley-Queisser limit efficiency, so perovskites still have considerable research potential. Perovskite adopts a sandwich structure, and its internal photogenerated carriers are transmitted by means of different interface layers, among which the hole transport layer plays a vital role in the transmission of holes.

[0003] Currently, the commonly used hole transport layers are nickel oxide, small molecule holes, PEDOT:PSS, etc., but these hole materials all have certain problems. For example, there are a large number of O and Ni defect vacancies in nickel oxide, which leads to serious carrier recombination. Small molecule holes have the problem of poor wettability. PEDOT:PSS has the disadvantages of poor device stability due to its hygroscopic characteristics and corrosion of ITO, which affects the carrier transport of perovskite and causes the decline of device performance. Summary of the invention

[0004] The purpose of the present invention is to provide a perovskite solar cell based on a composite hole transport layer and a preparation method thereof, so as to solve the problems existing in the above-mentioned prior art and realize the preparation of a perovskite solar cell device with high light conversion efficiency and high thermal stability.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is to provide a perovskite solar cell based on a composite hole transport layer, wherein the raw materials of the composite hole transport layer include a heteropoly acid salt and a small molecule hole material in a mass ratio of 0.5 to 1.5:1.

[0007] Furthermore, the perovskite solar cell comprises an ITO substrate, a composite hole transport layer, a perovskite light absorption layer, an electron transport layer and a metal electrode layer which are stacked in sequence.

[0008] Preferably, the heteropolyacid salt includes one or more of zinc phosphomolybdate, copper phosphomolybdate, tin phosphomolybdate, silver phosphomolybdate and nickel phosphomolybdate.

[0009] Preferably, the small molecule hole material includes one or more of 2PACz, 3PACz, 4PACz, 6PACz, Me-2PACz, Me-3PACz, Me-4PACz, Me-6PACz, MeO-2PACz, MeO-3PACz, MeO-4PACz, MeO-6PAC, V1036, CbzNaph and MTPA-BA.

[0010] Furthermore, the structural formula of the small molecule hole material is as follows:

[0011]

[0012] The existing technology uses heteropoly acid as the hole transport layer, and adopts various methods such as spin coating and coating to prepare the corresponding perovskite battery. However, due to the excessive acidity, small specific surface area, poor thermal stability and strong oxidizing property of heteropoly acid, NiO x The above-mentioned perovskite solar cell device based on the composite hole transport layer still has the problem of low photoelectric conversion efficiency, which affects its application. The present invention prepares a composite hole transport layer by using a specific amount of heteropolyacid salt and a small molecule hole material, which can effectively solve the problems existing in the above-mentioned prior art.

[0013] Preferably, the composite hole transport layer is a composite hole transport layer with a single-layer structure or a composite hole transport layer with a double-layer structure.

[0014] Preferably, the preparation step of the composite hole transport layer comprises: mixing a heteropoly acid salt, a small molecule hole material and a solvent to obtain a mixed solution; spin coating the mixed solution on an ITO substrate to form a composite hole transport layer with a single-layer structure;

[0015] The preparation steps of the double-layer composite hole transport layer include: firstly spin-coating a first mixed solution of a heteropolyacid salt and a solvent on an ITO substrate to form a heteropolyacid salt layer, and then spin-coating a second mixed solution of a small molecule hole material and a solvent on the heteropolyacid salt layer to form a double-layer composite hole transport layer.

[0016] Preferably, the concentrations of the mixed solutions are independently 0.5 to 2 mg / mL; the concentration of the first mixed solution is 0.5 to 2 mg / mL; and the concentration of the second mixed solution is 0.5 to 2 mg / mL.

[0017] The present invention selects a composite hole transport layer containing a specific concentration of heteropolyacid salt and a small molecule hole material to ensure that the heteropolyacid salt or the small molecule hole has good dispersion in the solvent, so as to ensure good film quality of the hole transport layer after subsequent film formation.

[0018] Preferably, the general formula of the material used in the perovskite light absorption layer of the perovskite solar cell is ABX 3 ; Where A is selected from MA + , FA + and Cs + One or more of; B is selected from Pb 2+ and / or Sn 2+ , X is selected from Cl - Br - and I - One or more of .

[0019] Furthermore, the general formula of the material used in the perovskite light absorption layer of the perovskite solar cell is preferably Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 The perovskite light absorption layer obtained by the material of the preferred general formula can better cooperate with the composite hole transport layer, and play the role of the composite hole transport layer in extracting good holes in the wide-bandgap perovskite system.

[0020] Preferably, the electron transport layer of the perovskite solar cell comprises an electron transport material layer and a modification layer which are stacked in sequence; the material used for the electron transport material layer comprises C60; and the material used for the modification layer comprises BCP.

[0021] Preferably, the thickness of the electron transport material layer is 10 to 30 nm; the thickness of the modification layer is 5 to 20 nm.

[0022] Preferably, the thickness of the composite hole transport layer is 10-30 nm; the thickness of the electron transport layer of the perovskite solar cell is 15-30 nm; the thickness of the modified layer is 5-20 nm. The thickness of the metal electrode layer of the perovskite solar cell is 80-150 nm.

[0023] Regarding the thickness of the above-mentioned functional layer, its thickness is ensured to be within the above-mentioned specified range to ensure that it plays a good role in promoting the transmission of perovskite carriers and inhibits the composite recombination behavior during the carrier transmission process.

[0024] Furthermore, the metal material used for the metal electrode layer of the perovskite solar cell includes silver, gold, copper, etc.

[0025] Furthermore, the perovskite solar cell based on the composite hole transport layer is a single-cell device, specifically a full perovskite tandem cell, a perovskite-crystalline silicon tandem cell or a perovskite-organic tandem cell.

[0026] The second technical solution of the present invention is to provide a method for preparing the above-mentioned perovskite solar cell based on the composite hole transport layer, comprising the following steps:

[0027] A composite hole transport layer, a perovskite light absorption layer, an electron transport layer and a metal electrode layer are sequentially stacked on an ITO substrate to obtain the perovskite solar cell based on the composite hole transport layer.

[0028] Furthermore, the configuration of the composite hole transport layer, perovskite light absorption layer, electron transport layer and metal electrode layer includes but is not limited to spin coating, scraping, atomic deposition or thermal evaporation; the spin coating speed is independently 1000-6000 r / min, and the time is independently 20-45 s.

[0029] Furthermore, the composite hole transport layer, the perovskite light absorption layer, the electron transport layer and the metal electrode layer further include an annealing step after the arrangement of each layer is completed; the annealing temperature is independently 60 to 150° C., and the time is independently 10 to 30 minutes.

[0030] Whether or not an annealing step is required depends on the inherent properties of the materials used to form each layer.

[0031] The technical mechanism of the present invention is as follows:

[0032] The present invention is aimed at the problems of poor wettability, serious non-radiative recombination and serious thermal stability attenuation of the hole transport layer materials of the current perovskite, and discloses a perovskite battery based on a composite hole transport layer of a heteropolyacid salt, the main function of which is that the composite hole transport layer of the heteropolyacid salt and the small molecule hole material can ensure efficient hole extraction and block the reverse transmission of electrons, reducing carrier recombination. It forms a gentle energy level gradient with the perovskite, reducing the energy level. It also forms a built-in electric field to accelerate the transmission of holes to the electrode, thereby effectively improving the extraction and transmission process of hole carriers, reducing the non-radiative recombination of the carrier transmission process, thereby improving the photoelectric conversion performance of the device, and the good thermal stability of the heteropolyacid salt greatly improves the thermal stability of the device.

[0033] The present invention uses zinc phosphomolybdate in heteropolyacid salts and small molecule hole materials to jointly construct the hole transport layer of perovskite, and uses heteropolyacid salts to improve the aggregation behavior of small molecules, optimize the film-forming behavior of small molecules during the small molecule film-forming process, break the orderly arrangement between molecules, increase the surface free energy, and thus improve the wettability. The adhesion between perovskite and the hole transport layer can be enhanced, thereby improving the problem of poor wettability in the prior art of preparing the hole transport layer using small molecule hole materials.

[0034] The present invention adopts zinc phosphomolybdate and small molecule hole materials in heteropolyacid salts to jointly construct the hole transport layer of perovskite. Compared with heteropolyacids, heteropolyacid salts exist in the form of salts and will not release hydrogen ions like heteropolyacids. Therefore, the acidity of the solution is weaker, thereby effectively solving the problems of heteropolyacid substances such as excessive acidity, small specific surface area, and poor thermal stability.

[0035] The present invention limits the mass ratio of the heteropolyacid salt and the small molecule hole material to 0.5-1.5:1. Within this range, good dispersion of the small molecule hole material and the heteropolyacid salt blend system can be achieved, or the small molecule hole material can form a good single-layer self-assembled structure on the heteropolyacid salt hole layer. Exceeding the upper limit of this range will cause the heteropolyacid salt to become turbid and precipitate due to poor solubility, resulting in poor film morphology of the composite layer and a serious decrease in battery performance.

[0036] The present invention discloses the following technical effects:

[0037] 1. The present invention uses zinc phosphomolybdate in heteropolyacid salts and small molecule hole materials to jointly construct the hole transport layer of perovskite, which can enhance the adhesion between the perovskite and the hole transport layer and improve the poor wettability of the small molecule hole material.

[0038] 2. The present invention can significantly improve the extraction and transmission rate of hole carriers in perovskite solar cell devices, inhibit the non-radiative recombination of perovskite, and reduce the defect density.

[0039] 3. The present invention can effectively improve the photoelectric conversion efficiency of perovskite solar cell devices by optimizing the carrier transmission path, and can improve the thermal stability of perovskite by utilizing the high stability of heteropolyacid salts. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the structure of the perovskite solar cell device described in Example 1 and Example 2;

[0041] Figure 2 The voltage-current density curves of the perovskite solar cell devices prepared in Examples 1 to 4 and Comparative Examples 1 to 6;

[0042] Figure 3 Steady-state fluorescence spectra of the perovskite solar cell devices prepared in Example 1, Example 2, Comparative Example 1 and Comparative Example 2;

[0043] Figure 4 These are the contact angle test results of the perovskite precursor solution and the hole transport layer described in Example 1, Example 2, Comparative Example 1 and Comparative Example 2. DETAILED DESCRIPTION

[0044] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0045] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0046] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0047] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0048] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0049] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in the art and are not the focus of the present invention.

[0050] Unless otherwise specified, the raw materials used in the following examples and comparative examples of the present invention are all commercially available products, and the sources of the commercially available products do not affect the technical effects of the present invention.

[0051] The room temperature involved in the present invention is 25±5°C unless otherwise specified.

[0052] Example 1

[0053] Step 1: Use an ITO substrate with a size of 1.5 cm×1.5 cm to clean the ITO substrate to remove dust and oil stains on the surface of the substrate. After the substrate is cleaned, use ozone ultraviolet treatment to further remove impurities from the surface of the substrate.

[0054] Step 2, Preparation of zinc molybdate and small molecule composite hole transport layer: Weigh 1 mg of zinc molybdate and 1 mg of 4PACz and dissolve them in 1 mL of ethanol. After stirring overnight at room temperature until completely dissolved, a precursor solution of zinc molybdate and small molecule composite hole transport layer is obtained. Use a pipette to measure 50 μL of the precursor solution of zinc molybdate and small molecule composite hole transport layer and spin-coat it on the ITO substrate obtained in Step 1 at a spin-coating speed of 3000 r / min. Then, perform annealing treatment at an annealing temperature of 100 °C for 10 min to form a composite hole transport layer of zinc molybdate and small molecules with a thickness of 25 nm.

[0055] Step 3, Preparation of 1.7 M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 Perovskite precursor preparation: Weigh 233.88 mg of FAI, 28.55 mg of MABr, 22.08 mg of CsI, 607.38 mg of PbI 2 , 140.38 mg of PbBr 2 and dissolve them in 1 mL of a mixed solvent of DMF and DMSO with a volume ratio of 4:1. Stir at room temperature for more than 4 h until the solid materials are completely dissolved. Then, filter using a 0.22 μm PTFE filter head and set aside for later use.

[0056] Step 4, Preparation of perovskite light-absorbing layer: The preparation of the perovskite active layer film is carried out in a nitrogen glove box. The specific steps are as follows: Use a pipette to measure 80 μL of 1.7 M Cs 0.0.5 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 perovskite precursor solution and spin-coat it on the formed composite hole transport layer of zinc molybdate and small molecules. The perovskite light-absorbing layer is prepared by a stepwise spin-coating method. Add 200 μL of chlorobenzene as an anti-solvent for perovskite crystallization 10 s before the end of stepwise spin-coating. After spin-coating, perform annealing treatment at an annealing temperature of 100 °C for 10 min to form a perovskite light-absorbing layer with a thickness of 600 nm.

[0057] Step 5, Preparation of electron transport layer: By means of vacuum evaporation, C60 and BCP are sequentially stacked on the formed perovskite light-absorbing layer to form an electron transport layer. The thickness of C60 is 20 nm, and the thickness of BCP is controlled to be 10 nm.

[0058] Step 6, preparation of a metal electrode layer: a silver electrode layer with a thickness of 120 nm is provided on the formed electron transport layer by vacuum evaporation.

[0059] Example 2

[0060] The difference from Example 1 is that step 2 is different from Example 1, and the other steps are the same as Example 1.

[0061] Specifically:

[0062] Step 1: Use an ITO substrate with a size of 1.5 cm×1.5 cm to clean the ITO substrate to remove dust and oil stains on the surface of the substrate. After the substrate is cleaned, use ozone ultraviolet treatment to further remove impurities from the surface of the substrate.

[0063] Step 2, preparation of the composite hole transport layer of the upper small molecule hole and the lower zinc phosphomolybdate: weigh 1 mg zinc phosphomolybdate and dissolve it in 1 mL ethanol, weigh 1 mg 4PACz and dissolve it in 1 mL ethanol, stir the two mixed solutions at room temperature overnight, and after the two mixed solutions are completely dissolved, the zinc phosphomolybdate precursor solution and the small molecule hole precursor solution can be obtained. Use a pipette to measure 50 μL of the zinc phosphomolybdate precursor solution, spin-coat it on the ITO substrate obtained in step 1, and the spin-coating speed is 5000 r / min to form a single zinc phosphomolybdate hole transport layer; then measure 30 μL of the small molecule hole precursor solution, and use a dynamic shaking method to spin-coat it on the single zinc phosphomolybdate hole transport layer at a spin-coating speed of 5000 r / min, and then anneal it, the annealing temperature is 100 ° C, and the time is 10 min, so that the composite hole transport layer of the upper small molecule hole and the lower zinc phosphomolybdate can be formed, with a thickness of 30 nm.

[0064] Step 3, 1.7M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 Preparation of perovskite precursor: weigh 233.88 mg FAI, 28.55 mg MABr, 22.08 mg CsI, 607.38 mg PbI 2 、140.38mg PbBr 2 The solid material was dissolved in 1 mL of a mixed solvent of DMF and DMSO in a volume ratio of 4:1, stirred at room temperature for more than 4 h until the solid material was completely dissolved, and then filtered through a 0.22 μm PTFE filter head for later use.

[0065] Step 4, preparation of perovskite light absorbing layer: Preparation of perovskite active layer film in a nitrogen glove box, the specific steps are as follows: 80 μL of 1.7 M Cs0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 The perovskite precursor solution is spin-coated on the formed upper small molecule holes and the lower zinc phosphomolybdate composite hole transport layer, and the perovskite light absorption layer is prepared by step-by-step spin coating. 200 μL of chlorobenzene is added 10 seconds before the end of the step-by-step spin coating as an anti-solvent for the crystallization of the perovskite. After the spin coating, annealing treatment is performed at 100°C for 10 minutes to form a perovskite light absorption layer with a thickness of 600 nm.

[0066] Step 5, preparation of electron transport layer: C60 and BCP are sequentially stacked on the formed perovskite light-absorbing layer by vacuum evaporation to form an electron transport layer, with the thickness of C60 being 20 nm and the thickness of BCP being controlled to be 10 nm.

[0067] Step 6, preparation of a metal electrode layer: a silver electrode layer with a thickness of 120 nm is provided on the formed electron transport layer by vacuum evaporation.

[0068] Example 3

[0069] The difference from Example 1 is that step 2 is different from Example 1, and the other steps are the same as Example 1.

[0070] Specifically:

[0071] Step 1: Use an ITO substrate with a size of 1.5 cm×1.5 cm to clean the ITO substrate to remove dust and oil stains on the surface of the substrate. After the substrate is cleaned, use ozone ultraviolet treatment to further remove impurities from the surface of the substrate.

[0072] Step 2, preparation of zinc phosphomolybdate and small molecule composite hole transport layer: weigh 1 mg zinc phosphomolybdate and 1 mg Me-2PACz respectively, blend and dissolve in 1 mL ethanol, stir overnight at room temperature to completely dissolve, and obtain a precursor solution of the phosphomolybdic acid and small molecule composite hole transport layer. Use a pipette to measure 50 μL of the precursor solution of zinc phosphomolybdate and small molecule composite hole transport layer, spin-coat on the ITO substrate obtained in step 1, the spin-coating speed is 3000 r / min, and then annealing is performed at an annealing temperature of 100°C for 10 minutes to form a composite hole transport layer of zinc phosphomolybdate and small molecules with a thickness of 25 nm.

[0073] Step 3, 1.7M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3Preparation of perovskite precursor: weigh 233.88 mg FAI, 28.55 mg MABr, 22.08 mg CsI, 607.38 mg PbI 2 、140.38mg PbBr 2 The solid material was dissolved in 1 mL of a mixed solvent of DMF and DMSO in a volume ratio of 4:1, stirred at room temperature for more than 4 h until the solid material was completely dissolved, and then filtered using a 0.22 μm PTFE filter head for later use.

[0074] Step 4, preparation of perovskite light absorbing layer: Preparation of perovskite active layer film was carried out in a nitrogen glove box. The specific steps are as follows: 80 μL of 1.7 M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 The perovskite precursor solution is spin-coated on the formed upper small molecule holes and the lower zinc phosphomolybdate composite hole transport layer, and the perovskite light absorption layer is prepared by step-by-step spin coating. 200 μL of chlorobenzene is added 10 seconds before the end of the step-by-step spin coating as an anti-solvent for the crystallization of the perovskite. After the spin coating, annealing treatment is performed at 100°C for 10 minutes to form a perovskite light absorption layer with a thickness of 600 nm.

[0075] Step 5, preparation of electron transport layer: C60 and BCP are sequentially stacked on the formed perovskite light-absorbing layer by vacuum evaporation to form an electron transport layer, with the thickness of C60 being 20 nm and the thickness of BCP being controlled to be 10 nm.

[0076] Step 6, preparation of a metal electrode layer: a silver electrode layer with a thickness of 120 nm is provided on the formed electron transport layer by vacuum evaporation.

[0077] Example 4

[0078] The difference from Example 1 is that step 2 is different from Example 1, and the other steps are the same as Example 1.

[0079] Specifically:

[0080] Step 1: Use an ITO substrate with a size of 1.5 cm×1.5 cm to clean the ITO substrate to remove dust and oil stains on the surface of the substrate. After the substrate is cleaned, use ozone ultraviolet treatment to further remove impurities from the surface of the substrate.

[0081] Step 2, preparation of tin phosphomolybdic acid and small molecule composite hole transport layer: weigh 1 mg tin phosphomolybdic acid and 1 mg 4PACz respectively, dissolve them in 1 mL ethanol, stir overnight at room temperature to dissolve completely, and obtain the precursor solution of phosphomolybdic acid and small molecule composite hole transport layer. Use a pipette to measure 50 μL of the precursor solution of zinc phosphomolybdic acid and small molecule composite hole transport layer, spin-coat it on the ITO substrate obtained in step 1, the spin-coating speed is 3000 r / min, and then annealing is performed at an annealing temperature of 100°C for 10 minutes to form a composite hole transport layer of zinc phosphomolybdic acid and small molecules with a thickness of 25 nm.

[0082] Step 3, 1.7M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 Preparation of perovskite precursor: weigh 233.88 mg FAI, 28.55 mg MABr, 22.08 mg CsI, 607.38 mg PbI 2 、140.38mg PbBr 2 The solid material was dissolved in 1 mL of a mixed solvent of DMF and DMSO in a volume ratio of 4:1, stirred at room temperature for more than 4 h until the solid material was completely dissolved, and then filtered using a 0.22 μm PTFE filter head for later use.

[0083] Step 4, preparation of perovskite light absorbing layer: Preparation of perovskite active layer film was carried out in a nitrogen glove box. The specific steps are as follows: 80 μL of 1.7 M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 The perovskite precursor solution is spin-coated on the formed upper small molecule holes and the lower zinc phosphomolybdate composite hole transport layer, and the perovskite light absorption layer is prepared by step-by-step spin coating. 200 μL of chlorobenzene is added 10 seconds before the end of the step-by-step spin coating as an anti-solvent for the crystallization of the perovskite. After the spin coating, annealing treatment is performed at 100°C for 10 minutes to form a perovskite light absorption layer with a thickness of 600 nm.

[0084] Step 5, preparation of electron transport layer: C60 and BCP are sequentially stacked on the formed perovskite light-absorbing layer by vacuum evaporation to form an electron transport layer, with the thickness of C60 being 20 nm and the thickness of BCP being controlled to be 10 nm.

[0085] Step 6, Preparation of the metal electrode layer: By means of vacuum evaporation, a silver electrode layer with a thickness of 120 nm is provided on the formed electron transport layer.

[0086] Comparative Example 1

[0087] The difference from Example 2 is that the small molecule holes in the composite hole transport layer are omitted, and the others are the same as in Example 2.

[0088] Specifically:

[0089] Step 1, Use an ITO substrate with a size of 1.5 cm × 1.5 cm. Clean the ITO substrate to remove dust, oil, etc. on the substrate surface. After cleaning the substrate, use ozone ultraviolet treatment to further remove impurities on the surface of the substrate.

[0090] Step 2, Preparation of the zinc molybdate single hole transport layer: Weigh 1 mg of zinc molybdate and dissolve it in 1 mL of ethanol. Stir overnight at room temperature. After complete dissolution, a zinc molybdate precursor solution can be obtained. Use a pipette to measure 50 μL of the zinc molybdate precursor solution and spin-coat it on the ITO substrate obtained in Step 1 at a spin-coating speed of 5000 r / min to form a zinc molybdate single hole transport layer. Then perform annealing treatment at an annealing temperature of 100 °C for 10 min to form a zinc molybdate single hole transport layer with a thickness of 15 nm.

[0091] Step 3, Preparation of 1.7 M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 Perovskite precursor: Weigh 233.88 mg of FAI, 28.55 mg of MABr, 22.08 mg of CsI, 607.38 mg of PbI 2 and 140.38 mg of PbBr 2 Dissolve in 1 mL of a mixed solvent of DMF and DMSO with a volume ratio of 4:1. Stir at room temperature for more than 4 h until the solid materials are completely dissolved. Then filter with a 0.22 μm PTFE filter head and set aside.

[0092] Step 4, Preparation of the perovskite light-absorbing layer: The preparation of the perovskite active layer film is carried out in a nitrogen glove box. The specific steps are as follows: Use a pipette to measure 80 μL of 1.7 M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3The perovskite precursor solution was spin-coated on the formed zinc phosphomolybdate single hole transport layer, and the perovskite light absorption layer was prepared by step-by-step spin coating. 200 μL of chlorobenzene was added 10 seconds before the end of the step-by-step spin coating as an anti-solvent for the crystallization of the perovskite. After the spin coating, an annealing treatment was performed at a temperature of 100°C for 10 minutes to form a perovskite light absorption layer with a thickness of 600 nm.

[0093] Step 5, preparation of electron transport layer: C60 and BCP are sequentially stacked on the formed perovskite light-absorbing layer by vacuum evaporation to form an electron transport layer, with the thickness of C60 being 20 nm and the thickness of BCP being controlled to be 10 nm.

[0094] Step 6, preparation of a metal electrode layer: a silver electrode layer with a thickness of 120 nm is provided on the formed electron transport layer by vacuum evaporation.

[0095] Comparative Example 2

[0096] The difference from Example 2 is that zinc phosphomolybdate in the composite hole transport layer is omitted, and the rest is the same as Example 2.

[0097] Specifically:

[0098] Step 1: Use an ITO substrate with a size of 1.5 cm×1.5 cm to clean the ITO substrate to remove dust and oil stains on the surface of the substrate. After the substrate is cleaned, use ozone ultraviolet treatment to further remove impurities from the surface of the substrate.

[0099] Step 2, preparation of a small molecule hole single hole transport layer: Weigh 1 mg of 4PACz and dissolve it in 1 mL of ethanol, stir it at room temperature overnight, and after it is completely dissolved, a small molecule hole precursor solution can be obtained. Measure 30 μL of the small molecule hole precursor solution, and spin-coat it on the ITO substrate obtained in step 1 at a spin coating speed of 5000 r / min by dynamic spinning, and then anneal it at a temperature of 100°C for 10 minutes to form a small molecule hole single hole transport layer with a thickness of 5 nm.

[0100] Step 3, 1.7M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 Preparation of perovskite precursor: weigh 233.88 mg FAI, 28.55 mg MABr, 22.08 mg CsI, 607.38 mg PbI 2 、140.38mg PbBr 2The solid material was dissolved in 1 mL of a mixed solvent of DMF and DMSO in a volume ratio of 4:1, stirred at room temperature for more than 4 h until the solid material was completely dissolved, and then filtered through a 0.22 μm PTFE filter head for later use.

[0101] Step 4, preparation of perovskite light absorbing layer: Preparation of perovskite active layer film in a nitrogen glove box, the specific steps are as follows: 80 μL of 1.7 M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 The perovskite precursor solution was spin-coated on the formed small molecule hole single hole transport layer, and the perovskite light absorption layer was prepared by step-by-step spin coating. 200 μL of chlorobenzene was added 10 seconds before the end of the step-by-step spin coating as an anti-solvent for the crystallization of the perovskite. After the spin coating, an annealing treatment was performed at a temperature of 100°C for 10 minutes to form a perovskite light absorption layer with a thickness of 600 nm.

[0102] Step 5, preparation of electron transport layer: C60 and BCP are sequentially stacked on the formed perovskite light-absorbing layer by vacuum evaporation to form an electron transport layer, with the thickness of C60 being 20 nm and the thickness of BCP being controlled to be 10 nm.

[0103] Step 6, preparation of a metal electrode layer: a silver electrode layer with a thickness of 120 nm is provided on the formed electron transport layer by vacuum evaporation.

[0104] Comparative Example 3

[0105] The difference from Example 1 is that step 2 is different from Example 1, and the other steps are the same as Example 1.

[0106] Specifically:

[0107] Step 1: Use an ITO substrate with a size of 1.5 cm×1.5 cm to clean the ITO substrate to remove dust and oil stains on the surface of the substrate. After the substrate is cleaned, use ozone ultraviolet treatment to further remove impurities from the surface of the substrate.

[0108] Step 2, preparation of zinc phosphomolybdate and small molecule composite hole transport layer: weigh 2 mg zinc phosphomolybdate and 1 mg 4PACz respectively, blend and dissolve in 1 mL ethanol, stir overnight at room temperature to completely dissolve, and obtain a precursor solution of phosphomolybdic acid and small molecule composite hole transport layer. Use a pipette to measure 50 μL of the precursor solution of zinc phosphomolybdate and small molecule composite hole transport layer, spin-coat on the ITO substrate obtained in step 1, the spin-coating speed is 3000 r / min, and then annealing is performed at an annealing temperature of 100°C for 10 minutes to form a composite hole transport layer of zinc phosphomolybdate and small molecules with a thickness of 30 nm.

[0109] Step 3, 1.7M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 Preparation of perovskite precursor: weigh 233.88 mg FAI, 28.55 mg MABr, 22.08 mg CsI, 607.38 mg PbI 2 、140.38mg PbBr 2 The solid material was dissolved in 1 mL of a mixed solvent of DMF and DMSO in a volume ratio of 4:1, stirred at room temperature for more than 4 h until the solid material was completely dissolved, and then filtered through a 0.22 μm PTFE filter head for later use.

[0110] Step 4, preparation of perovskite light absorbing layer: Preparation of perovskite active layer film in a nitrogen glove box, the specific steps are as follows: 80 μL of 1.7 M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 The perovskite precursor solution is spin-coated on the formed upper small molecule holes and the lower zinc phosphomolybdate composite hole transport layer, and the perovskite light absorption layer is prepared by step-by-step spin coating. 200 μL of chlorobenzene is added 10 seconds before the end of the step-by-step spin coating as an anti-solvent for the crystallization of the perovskite. After the spin coating, annealing treatment is performed at 100°C for 10 minutes to form a perovskite light absorption layer with a thickness of 600 nm.

[0111] Step 5, preparation of electron transport layer: C60 and BCP are sequentially stacked on the formed perovskite light-absorbing layer by vacuum evaporation to form an electron transport layer, with the thickness of C60 being 20 nm and the thickness of BCP being controlled to be 10 nm.

[0112] Step 6, preparation of a metal electrode layer: a silver electrode layer with a thickness of 120 nm is provided on the formed electron transport layer by vacuum evaporation.

[0113] Comparative Example 4

[0114] The difference from Example 1 is that step 2 is different from Example 1, and the other steps are the same as Example 1.

[0115] Specifically:

[0116] Step 1: Use an ITO substrate with a size of 1.5 cm×1.5 cm to clean the ITO substrate to remove dust and oil stains on the surface of the substrate. After the substrate is cleaned, use ozone ultraviolet treatment to further remove impurities from the surface of the substrate.

[0117] Step 2, preparation of zinc phosphomolybdate and small molecule composite hole transport layer: weigh 1 mg zinc phosphomolybdate and 2 mg 4PACz respectively, blend and dissolve in 1 mL ethanol, stir overnight at room temperature to dissolve completely, and obtain a precursor solution of phosphomolybdic acid and small molecule composite hole transport layer. Use a pipette to measure 50 μL of the precursor solution of zinc phosphomolybdate and small molecule composite hole transport layer, spin-coat on the ITO substrate obtained in step 1, the spin-coating speed is 3000 r / min, and then annealing is performed at an annealing temperature of 100 ° C for 10 minutes to form a composite hole transport layer of zinc phosphomolybdate and small molecules with a thickness of 30 nm.

[0118] Step 3, 1.7M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 Preparation of perovskite precursor: weigh 233.88 mg FAI, 28.55 mg MABr, 22.08 mg CsI, 607.38 mg PbI 2 、140.38mg PbBr 2 The solid material was dissolved in 1 mL of a mixed solvent of DMF and DMSO in a volume ratio of 4:1, stirred at room temperature for more than 4 h until the solid material was completely dissolved, and then filtered using a 0.22 μm PTFE filter head for later use.

[0119] Step 4, preparation of perovskite light absorbing layer: Preparation of perovskite active layer film was carried out in a nitrogen glove box. The specific steps are as follows: 80 μL of 1.7 M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3The perovskite precursor solution is spin-coated on the formed upper small molecule holes and the lower zinc phosphomolybdate composite hole transport layer, and the perovskite light absorption layer is prepared by step-by-step spin coating. 200 μL of chlorobenzene is added 10 seconds before the end of the step-by-step spin coating as an anti-solvent for the crystallization of the perovskite. After the spin coating, annealing treatment is performed at 100°C for 10 minutes to form a perovskite light absorption layer with a thickness of 600 nm.

[0120] Step 5, preparation of electron transport layer: C60 and BCP are sequentially stacked on the formed perovskite light-absorbing layer by vacuum evaporation to form an electron transport layer, with the thickness of C60 being 20 nm and the thickness of BCP being controlled to be 10 nm.

[0121] Step 6, preparation of a metal electrode layer: a silver electrode layer with a thickness of 120 nm is provided on the formed electron transport layer by vacuum evaporation.

[0122] Comparative Example 5

[0123] The difference from Example 1 is that step 2 is different from Example 1, and the other steps are the same as Example 1.

[0124] Specifically:

[0125] Step 1: Use an ITO substrate with a size of 1.5 cm×1.5 cm to clean the ITO substrate to remove dust and oil stains on the surface of the substrate. After the substrate is cleaned, use ozone ultraviolet treatment to further remove impurities from the surface of the substrate.

[0126] Step 2, preparation of zinc phosphomolybdate and small molecule composite hole transport layer: weigh 0.5 mg zinc phosphomolybdate and 1 mg 4PACz respectively, blend and dissolve in 1 mL ethanol, stir overnight at room temperature to dissolve completely, and obtain a precursor solution of phosphomolybdic acid and small molecule composite hole transport layer. Use a pipette to measure 50 μL of the precursor solution of zinc phosphomolybdate and small molecule composite hole transport layer, spin-coat on the ITO substrate obtained in step 1, the spin-coating speed is 3000 r / min, and then annealing is performed at an annealing temperature of 100 ° C for 10 minutes to form a composite hole transport layer of zinc phosphomolybdate and small molecules with a thickness of 20 nm.

[0127] Step 3, 1.7M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 Preparation of perovskite precursor: weigh 233.88 mg FAI, 28.55 mg MABr, 22.08 mg CsI, 607.38 mg PbI 2 、140.38mg PbBr2 The solid material was dissolved in 1 mL of a mixed solvent of DMF and DMSO in a volume ratio of 4:1, stirred at room temperature for more than 4 h until the solid material was completely dissolved, and then filtered using a 0.22 μm PTFE filter head for later use.

[0128] Step 4, preparation of perovskite light absorbing layer: Preparation of perovskite active layer film was carried out in a nitrogen glove box. The specific steps are as follows: 80 μL of 1.7 M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 The perovskite precursor solution is spin-coated on the formed upper small molecule holes and the lower zinc phosphomolybdate composite hole transport layer, and the perovskite light absorption layer is prepared by step-by-step spin coating. 200 μL of chlorobenzene is added 10 seconds before the end of the step-by-step spin coating as an anti-solvent for the crystallization of the perovskite. After the spin coating, annealing treatment is performed at 100°C for 10 minutes to form a perovskite light absorption layer with a thickness of 600 nm.

[0129] Step 5, preparation of electron transport layer: C60 and BCP are sequentially stacked on the formed perovskite light-absorbing layer by vacuum evaporation to form an electron transport layer, with the thickness of C60 being 20 nm and the thickness of BCP being controlled to be 10 nm.

[0130] Step 6, preparation of a metal electrode layer: a silver electrode layer with a thickness of 120 nm is provided on the formed electron transport layer by vacuum evaporation.

[0131] Comparative Example 6

[0132] The difference from Example 1 is that step 2 is different from Example 1, and the other steps are the same as Example 1.

[0133] Specifically:

[0134] Step 1: Use an ITO substrate with a size of 1.5 cm×1.5 cm to clean the ITO substrate to remove dust and oil stains on the surface of the substrate. After the substrate is cleaned, use ozone ultraviolet treatment to further remove impurities from the surface of the substrate.

[0135] Step 2, preparation of zinc phosphomolybdate and small molecule composite hole transport layer: weigh 1 mg zinc phosphomolybdate and 0.5 mg 4PACz respectively, blend and dissolve in 1 mL ethanol, stir overnight at room temperature to dissolve completely, and obtain a precursor solution of phosphomolybdic acid and small molecule composite hole transport layer. Use a pipette to measure 50 μL of the precursor solution of zinc phosphomolybdate and small molecule composite hole transport layer, spin-coat on the ITO substrate obtained in step 1, the spin-coating speed is 3000 r / min, and then annealing is performed at an annealing temperature of 100 ° C for 10 minutes to form a composite hole transport layer of zinc phosphomolybdate and small molecules with a thickness of 22 nm.

[0136] Step 3, 1.7M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 Preparation of perovskite precursor: weigh 233.88 mg FAI, 28.55 mg MABr, 22.08 mg CsI, 607.38 mg PbI 2 、140.38mg PbBr 2 The solid material was dissolved in 1 mL of a mixed solvent of DMF and DMSO in a volume ratio of 4:1, stirred at room temperature for more than 4 h until the solid material was completely dissolved, and then filtered using a 0.22 μm PTFE filter head for later use.

[0137] Step 4, preparation of perovskite light absorbing layer: Preparation of perovskite active layer film was carried out in a nitrogen glove box. The specific steps are as follows: 80 μL of 1.7 M Cs 0.05 FA 0.8 MA 0.15 Pb(I 0.8 Br 0.2 ) 3 The perovskite precursor solution is spin-coated on the formed upper small molecule holes and the lower zinc phosphomolybdate composite hole transport layer, and the perovskite light absorption layer is prepared by step-by-step spin coating. 200 μL of chlorobenzene is added 10 seconds before the end of the step-by-step spin coating as an anti-solvent for the crystallization of the perovskite. After the spin coating, annealing treatment is performed at 100°C for 10 minutes to form a perovskite light absorption layer with a thickness of 600 nm.

[0138] Step 5, preparation of electron transport layer: C60 and BCP are sequentially stacked on the formed perovskite light-absorbing layer by vacuum evaporation to form an electron transport layer, with the thickness of C60 being 20 nm and the thickness of BCP being controlled to be 10 nm.

[0139] Step 6, preparation of a metal electrode layer: a silver electrode layer with a thickness of 120 nm is provided on the formed electron transport layer by vacuum evaporation.

[0140] Performance Test:

[0141] The photoelectric conversion efficiency of the perovskite solar cell devices prepared in Examples 1 to 4 and Comparative Examples 1 to 6 was tested using AAA-level steady-state solar simulation and corresponding IV test system. The test results of each example and comparative example are based on the optimal device performance and average device performance of 6 groups of devices. The specific open circuit voltage (V OC ), short-circuit current density (J SC The test results of ), fill factor (FF) and photoelectric conversion efficiency (PCE) are shown in Table 1.

[0142] Table 1 Performance test results of perovskite solar cell devices prepared in Examples 1 to 4 and Comparative Examples 1 to 6

[0143]

[0144] As can be seen from Table 1, the performance of the perovskite solar cell device of the composite hole transport layer of zinc phosphomolybdate and small molecule hole material provided by the present invention is better than that of the perovskite solar cell device composed of a single zinc phosphomolybdate or a small molecule hole material, which is mainly manifested in the improvement of the filling factor and voltage. This shows that the composite hole transport layer composed of zinc phosphomolybdate and small molecule hole material has greatly improved the adhesion between the hole transport layer and the perovskite light absorbing layer, and there is better contact between the interfaces, which provides a better channel for the transmission of internal carriers and suppresses non-radiative recombination. The corresponding IV test curve is as follows: Figure 2 shown.

[0145] Figure 2 The voltage-current density curves of the perovskite solar cell devices prepared in Examples 1 to 4 and Comparative Examples 1 to 6 are shown in FIG. Figure 2 It can be seen that the device performance of Examples 1 to 4 is better than that of Comparative Examples 1 to 6, among which the best performance is Example 3 (composite hole transport layer of Me-2PACz and zinc phosphomolybdate), in which J SC =22.56mA / cm 2 , V OC =1.14V, FF=82.85%, PCE=21.37%. In addition, the performance of Example 4 (4PACz and tin phosphomolybdate composite transport layer) is J SC =22.37mA / cm 2 , V OC=1.13V, FF=81.82%, PCE=20.62%, which shows the universality of the composite hole transport layer of heteropolyacid salt and small molecule hole. In addition, the device performance based on different concentrations of zinc phosphomolybdate and 4PACz shows that the performance of the composite hole based on 1mg zinc phosphomolybdate and 1mg 4PACz blend is the best.

[0146] Figure 3 The steady-state fluorescence spectra of the perovskite solar cell devices prepared in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 are shown in Figure 1. The steady-state fluorescence spectra are used to investigate the transport of hole carriers. Figure 3 It can be seen that Example 1 and Example 2 show lower fluorescence intensity than Comparative Example 1 and Comparative Example 2, indicating that the internal defect density is low and the transport and recombination of carriers are suppressed. It can be seen that the composite hole transport layer of the present invention can effectively improve the transport of carriers, thereby improving device performance.

[0147] Figure 4 The contact angle test results of the perovskite solution and the hole transport layer described in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 are shown. The wettability of the perovskite precursor was tested using the contact angle test. Example 1 showed the smallest contact angle of 19.75°, and the contact angles of Example 2, Comparative Example 1 and Comparative Example 2 were 35.67°, 23.74° and 40.32° respectively. Among them, the contact angle of the single hole transport layer based on small molecule holes was the largest, indicating that its wettability was poor. The above results show that zinc phosphomolybdate can improve the wettability of small molecule holes, thereby improving device performance.

[0148] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0149] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A perovskite solar cell based on a composite hole transport layer, characterized in that: The raw materials of the composite hole transport layer include heteropoly acid salt and small molecule hole material in a mass ratio of 0.5 to 1.5:

1.

2. The perovskite solar cell based on a composite hole transport layer according to claim 1, characterized in that: The heteropoly acid salt includes one or more of zinc phosphomolybdate, copper phosphomolybdate, tin phosphomolybdate, silver phosphomolybdate and nickel phosphomolybdate.

3. The perovskite solar cell according to claim 1, characterized in that The small molecule hole material includes one or more of 2PACz, 3PACz, 4PACz, 6PACz, Me-2PACz, Me-3PACz, Me-4PACz, Me-6PACz, MeO-2PACz, MeO-3PACz, MeO-4PACz, MeO-6PAC, V1036, CbzNaph and MTPA-BA.

4. The perovskite solar cell based on a composite hole transport layer according to claim 1, characterized in that: The composite hole transport layer is a composite hole transport layer of a single-layer structure or a composite hole transport layer of a double-layer structure; and / or, the preparation steps of the composite hole transport layer of the single-layer structure include: mixing a heteropoly acid salt, a small molecule hole material and a solvent to obtain a mixed solution; spin coating the mixed solution on an ITO substrate to form a composite hole transport layer of a single-layer structure; The preparation steps of the double-layer composite hole transport layer include: firstly spin-coating a first mixed solution of a heteropolyacid salt and a solvent on an ITO substrate to form a heteropolyacid salt layer, and then spin-coating a second mixed solution of a small molecule hole material and a solvent on the heteropolyacid salt layer to form a double-layer composite hole transport layer.

5. The perovskite solar cell based on a composite hole transport layer according to claim 4, characterized in that: The concentration of the mixed solution is 0.5 to 2 mg / mL; and / or, the concentration of the first mixed solution is 0.5 to 2 mg / mL; and / or, the concentration of the second mixed solution is 0.5 to 2 mg / mL.

6. The perovskite solar cell based on a composite hole transport layer according to claim 1, characterized in that: The electron transport layer of the perovskite solar cell comprises an electron transport material layer and a modification layer which are stacked in sequence; the material used in the electron transport material layer comprises C60; and the material used in the modification layer comprises BCP.

7. The perovskite solar cell based on a composite hole transport layer according to claim 6, characterized in that: The thickness of the electron transport material layer is 10 to 30 nm; the thickness of the modification layer is 5 to 20 nm.

8. The perovskite solar cell based on a composite hole transport layer according to claim 1, characterized in that: The general formula of the material used for the perovskite light absorption layer of the perovskite solar cell is ABX3; wherein A is selected from MA + , FA + and Cs + One or more of; B is selected from Pb 2+ and / or Sn 2+ ; X is selected from Cl - Br - and I - One or more of .

9. The perovskite solar cell based on a composite hole transport layer according to claim 1, characterized in that: The thickness of the composite hole transport layer is 10 to 30 nm; and / or the thickness of the electron transport layer of the perovskite solar cell is 15 to 30 nm; and / or the thickness of the metal electrode layer of the perovskite solar cell is 80 to 150 nm.

10. The method for preparing a perovskite solar cell based on a composite hole transport layer according to any one of claims 1 to 9, characterized in that: The steps include: A composite hole transport layer, a perovskite light absorption layer, an electron transport layer and a metal electrode layer are sequentially stacked on an ITO substrate to obtain the perovskite solar cell based on the composite hole transport layer.

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