Perovskite solar cell with alendronate sodium lower interface modification layer and preparation method thereof

Abstract

The invention discloses a perovskite solar cell with an alendronate sodium phosphate lower interface modification layer and a preparation method of the perovskite solar cell, and belongs to the technical field of photovoltaic device materials. The perovskite solar cell comprises a conductive substrate, an electron transport layer, an alendronate sodium phosphate lower interface modification layer, a perovskite layer, a hole transport layer and a metal electrode which are sequentially stacked from bottom to top, the preparation method comprises the following steps: preparing an electron transport layer on a pretreated conductive substrate, spin-coating an alendronate sodium aqueous solution on the electron transport layer, and annealing to prepare an alendronate sodium lower interface modification layer; and sequentially preparing a perovskite layer and a hole transport layer on the alendronate sodium phosphate lower interface modification layer, and evaporating a metal electrode on the hole transport layer. According to the perovskite solar cell, the distribution uniformity of the electron transport layer is improved, the perovskite crystallization process can be delayed, the perovskite thin film with larger crystal grains and fewer defects is obtained, and therefore the photoelectric conversion efficiency of the perovskite solar cell is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic device materials, and in particular to a perovskite solar cell with an alendronate lower interface modification layer and a preparation method thereof. Background Art

[0002] Organic-inorganic hybrid perovskite materials possess unique optoelectronic properties, such as a suitable band gap, high absorption coefficient, long carrier diffusion length and lifetime, small exciton binding energy, and bipolar charge transport properties. These materials have attracted widespread attention and are widely used in solar cells, lasers, light-emitting diodes, and other fields. Perovskite solar cells, constructed with organic-inorganic hybrid perovskites as the light-absorbing layer, have become a rising star in the photovoltaic field due to their rapid efficiency increases. Currently, the photoelectric conversion efficiency of single-junction perovskite cells has exceeded 27%, but still falls short of the theoretical maximum efficiency. This is primarily due to defects in the perovskite film, particularly at the interface between the perovskite and electron transport layers. The crystallization process of perovskite films often affects their defects. If the electron transport layer is unevenly distributed or the conditions are improperly controlled during the perovskite crystallization process, uneven crystal growth can occur, increasing the number of defects at the grain boundaries. These defects not only affect the transport and extraction of charge carriers, thereby affecting the photoelectric conversion efficiency of perovskite cells, but may also become adsorption sites for water and oxygen, accelerating the degradation of perovskite films. Therefore, interface defects in perovskite solar cells remain a key factor restricting their photoelectric conversion efficiency and device stability. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a perovskite solar cell with an alendronate lower interface modification layer to solve the problems of interface defects under the perovskite film and uneven distribution of the electron transport layer in the prior art.

[0004] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0005] A perovskite solar cell with an alendronate lower interface modification layer comprises a conductive substrate, an electron transport layer, an alendronate lower interface modification layer, a perovskite layer, a hole transport layer and a metal electrode which are sequentially stacked from bottom to top.

[0006] As a preferred embodiment of the present invention, the lower interface modification layer of sodium alendronate is prepared by spin-coating an aqueous solution of sodium alendronate onto the electron transport layer to form a thin film, followed by annealing. The chemical structure of sodium alendronate is as follows:

[0007]

[0008] More preferably, the concentration of the alendronate sodium aqueous solution is 0.5-2 mg / mL, preferably 0.5, 1, or 2 mg / mL.

[0009] As a preferred embodiment of the present invention, the electron transport layer is a tin oxide coating.

[0010] Further preferably, the tin oxide coating is prepared by forming a thin film of a SnO2 solution having a concentration of 2-4 mg / mL on a conductive substrate and annealing the film. Preferably, the concentration of SnO2 is 2, 3, or 4 mg / mL.

[0011] As a preferred embodiment of the present invention, the molar concentration of the precursor solution of the perovskite layer is 1.5-1.6 mol / L, the solute includes MAI, FABr, CsI, MACl, PbBr2, FAI and PbI2 in a molar ratio of 1: (2.5-3): (2-2.5): (11-12.5):, (2.5-3): (25-29): (30-34), and the solvent is a mixed solution of DMF and DMSO in a volume ratio of 3:1.

[0012] The present invention also provides a method for preparing the above-mentioned perovskite solar cell having an alendronate lower interface modification layer, which comprises the following steps:

[0013] S1. Pre-treating the conductive substrate;

[0014] S2. preparing an electron transport layer on a conductive substrate;

[0015] S3, spin-coating an aqueous solution of sodium alendronate on the electron transport layer and annealing the layer to obtain a lower interface modification layer of sodium alendronate;

[0016] S4, preparing a perovskite layer on the lower interface modification layer of sodium alendronate;

[0017] S5. preparing a hole transport layer on the perovskite layer;

[0018] S6. Vapor-depositing a metal electrode on the hole transport layer.

[0019] As a preferred embodiment of the present invention, step S1 specifically includes the following steps:

[0020] S11, after scrubbing the conductive substrate with a detergent, placing the conductive substrate in water for ultrasonic cleaning for 15-20 minutes; preferably, the ultrasonic cleaning treatment time is preferably 17 minutes;

[0021] S12, placing the conductive substrate in ethanol and isopropanol in sequence and ultrasonically cleaning for 15-20 minutes; preferably, the ultrasonic cleaning treatment time is preferably 17 minutes;

[0022] S13. Ultrasonic cleaning the conductive substrate in a 5-15% by mass hydrogen peroxide solution for 10-15 minutes, followed by drying and plasma cleaning for 15-20 minutes. The concentration of the hydrogen peroxide solution is preferably 5%, 10%, or 15%. The ultrasonic cleaning time is preferably 12 minutes, and the plasma cleaning time is preferably 15 minutes.

[0023] As a preferred embodiment of the present invention, the hole transport layer in step S5 is prepared by spin coating a Spiro-OMeTAD solution on the perovskite layer, wherein the Spiro-OMeTAD solution is a solution in which Spiro-OMeTAD is dissolved in a mixed solvent and has a concentration of 0.05-0.08 mol / L; wherein the mixed solvent is composed of chlorobenzene, a Li-TFSI acetonitrile solution with a concentration of 1.75-2 mol / L, and a 4-tert-butylpyridine solution with a concentration of 0.4-0.6 mol / L in a volume ratio of 1: (0.015-0.02): (0.025-0.03).

[0024] As a preferred embodiment of the present invention, the conductive substrate is FTO or ITO.

[0025] As a preferred embodiment of the present invention, the metal electrode is Ag or Au, preferably the metal electrode is Ag.

[0026] As a preferred embodiment of the present invention, the thickness of the metal electrode is 100-120 nm, preferably 100 nm.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention forms an interface modification layer under alendronate by adding a crystallization / passivation regulator alendronate between the electron transport layer and the perovskite layer, which plays a double interface modification role: alendronate can produce a chemical interaction with SnO2, inhibiting the formation of defects in the SnO2 film; at the same time, the P=O and -OH of alendronate can react with Pb 2+ , FA + Lewis acid-base coordination and hydrogen bonding occur between ions. The interaction between the above functional groups can effectively reduce the uncoordinated Pb in the perovskite. 2+ ions while stabilizing the perovskite octahedral framework. This shows that compared to traditional perovskite solar cells, the present invention's use of sodium alendronate as a lower interface modification layer can make the surface of the SnO2 electron transport layer smoother and denser, while also passivating the perovskite's lower interface defects. This effectively reduces the holes formed during the growth of the perovskite film, thereby improving the quality of the perovskite film.

[0029] In summary, the perovskite solar cell of the present invention not only improves the distribution uniformity of the electron transport layer, but also can delay the perovskite crystallization process, thereby obtaining a perovskite film with larger grains and fewer defects, greatly improving the quality of the perovskite film, thereby making the perovskite solar cell have higher photoelectric conversion efficiency and better long-term stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 Steady-state photoluminescence images (a) and visible light absorption spectra (b) of Experimental Examples 1-4 of the present invention;

[0032] Figure 2 The electron microscope scanning images of Experimental Examples 1 and 3 of the present invention are shown in FIG. Figure 2 a and Figure 2 c are the electron microscope scanning images of the top and bottom of the electron transport layer of Experimental Example 1, Figure 2 b and Figure 2 d are scanning electron microscope images of the top and bottom of the electron transport layer of Experimental Example 3;

[0033] Figure 3 The AFM images of SnO2 and perovskite films in Experimental Examples 1 and 3 of the present invention are shown. Figure 3 (a) Perovskite AFM of Experimental Example 1; Figure 3 (b) Perovskite AFM of Experimental Example 3; Figure 3 (c) is the SnO2AFM image of Experimental Example 1; Figure 3 (d) is the SnO2AFM image of Experimental Example 3;

[0034] Figure 4 (a) TRPL images of the perovskite films of Experimental Examples 1 and 3 of the present invention; Figure 4 (b) XRD patterns of the perovskite films of Experimental Examples 1 and 3 of the present invention;

[0035] Figure 5 This is the infrared spectrum of the reaction between sodium alendronate and the perovskite component in 1.2 of the present invention. Figure 5 (a) is the infrared spectrum of the reaction of alendronate sodium with FAI; Figure (5b) is the infrared spectrum of the reaction of alendronate sodium with PbI2;

[0036] Figure 6The photoelectron spectra of SnO2 and SnO2-Alds in 1.3 of the present invention;

[0037] Figure 7 This is a comparison chart of the photoelectric efficiency of devices measured in Comparative Examples 1-4 of the present invention;

[0038] Figure 8 This is a comparison chart of the photoelectric efficiency of the devices measured in Examples 1-3 of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] The method for preparing a perovskite solar cell with an alendronate lower interface modification layer provided by the present invention comprises the following steps:

[0041] S1. Pre-treating the conductive substrate, specifically comprising the following steps:

[0042] S11, after scrubbing the conductive substrate with a detergent, the conductive substrate is placed in water for ultrasonic cleaning for 15-20 minutes;

[0043] S12, placing the conductive substrate in ethanol for ultrasonic cleaning for 15-20 minutes, and then placing it in isopropyl alcohol for ultrasonic cleaning for 15-20 minutes;

[0044] S13, placing the conductive substrate in a 5-15% hydrogen peroxide solution and ultrasonically cleaning it for 10-15 minutes, drying it, and plasma cleaning it for 15-20 minutes;

[0045] S2. Spin-coating a SnO2 solution with a concentration of 2-4 mg / mL on the pretreated conductive substrate, first keeping it at 90-120°C, and then annealing it at 180-220°C for 30-50 min to prepare an electron transport layer;

[0046] S3, spin coating an aqueous solution of sodium alendronate with a concentration of 0.5-2 mg / mL on the electron transport layer at 3500-4500 rpm for 25-35 seconds, and annealing at 80-120° C. for 10-20 minutes to prepare a lower interface modification layer of sodium alendronate;

[0047] S4. Spin-coating a perovskite precursor solution on the lower interface modification layer of sodium alendronate, and annealing after the spin coating is completed to obtain a perovskite layer; wherein the molar concentration of the precursor solution of the perovskite layer is 1.5-1.6 mol / L, the solutes include MAI, FABr, CsI, MACl, PbBr2, FAI and PbI2 in a molar ratio of 1:(2.5-3):(2-2.5):(11-12.5):, (2.5-3):(25-29):(30-34), and the solvent is a mixed solution of DMF and DMSO in a volume ratio of 3:1;

[0048] S5. Spin-coat a Spiro-OMeTAD solution on the perovskite layer to prepare a hole transport layer; wherein the Spiro-OMeTAD solution is a solution in which Spiro-OMeTAD is dissolved in a mixed solvent with a concentration of 0.05-0.08 mol / L; wherein the mixed solvent is composed of chlorobenzene, a Li-TFSI acetonitrile solution with a concentration of 1.75-2 mol / L, and a 4-tert-butylpyridine solution with a concentration of 0.4-0.6 mol / L in a volume ratio of 1:(0.015-0.02):(0.025-0.03).

[0049] S6. Vapor-deposit a metal electrode with a thickness of 100-120 nm on the hole transport layer.

[0050] In the above method, the conductive substrate is FTO or ITO; and the metal electrode is Ag or Au.

[0051] The perovskite solar cell structure prepared by the above method includes a conductive substrate, an electron transport layer, an alendronate lower interface modification layer, a perovskite layer, a hole transport layer and a metal electrode stacked in sequence from bottom to top.

[0052] 1. Investigation of the impact of sodium alendronate on performance

[0053] 1.1 Effect of Alendronate Interface Modification Layer on Optical Properties and Morphology

[0054] In order to investigate the effect of alendronate sodium concentration on device performance, different concentrations of alendronate sodium were used as a single variable to prepare the semi-finished devices of Experimental Examples 1 to 4 as follows. The specific preparation process is as follows:

[0055] S1. Pre-treating the conductive substrate: After scrubbing the FTO with a detergent, immerse the FTO in deionized water, 75% ethanol, and isopropanol solutions for ultrasonic cleaning for 17 minutes each; ultrasonically clean the FTO in a 10% hydrogen peroxide solution for 12 minutes, then dry it, and treat it with plasma bombardment for 15 minutes before use;

[0056] S2. 40 μL of a 1 mg / mL SnO2 solution was added to the pretreated FTO and spin-coated at 4000 rpm for 30 s. After spin-coating, the solution was kept at 100°C for 30 min and then annealed at 200°C for 40 min to prepare an electron transport layer.

[0057] S3, drop 60 μL of an aqueous solution of sodium alendronate of different concentrations onto the electron transport layer and spin-coat at 4000 rpm for 30 seconds, followed by annealing at 100°C for 10 minutes to prepare a lower interface modification layer of sodium alendronate;

[0058] S4. Take 3.2mg MAI, 6.8mg FABr, 12.3mg CsI, 16mg MACI, 19.8mg PbBr2, 95.2mg FAI and 295.6mg PbI2 and add them to a solvent composed of 100uL DMF and 400uL DMSO. After they are completely dissolved, a perovskite precursor solution is obtained. 45uL of the perovskite precursor solution is spin-coated on the sodium alendronate lower interface modification layer in multiple steps: the spin-coating speed of the first stage is 1000rpm for 10s and the acceleration is 500rpm / s. The spin-coating speed of the second stage is 4000rpm for 30s and the acceleration is 1000rpm / s. At the 30th second, 200uL EA of the anti-solvent is added dropwise. After the spin coating is completed, annealing is carried out at 100°C for 40min to obtain the perovskite layer.

[0059] Table 1 Alendronate sodium concentrations in Experimental Examples 1 to 4

[0060] project Alendronate sodium concentration (mg / mL) Experimental Example 1 0 Experimental Example 2 0.5 Experimental Example 3 1 Experimental Example 4 2

[0061] 1.1.1 The semi-finished device was tested for steady-state photoluminescence and absorption spectrum at wavelengths of 700-850nm and 500-850nm, respectively. The results are as follows: Figure 1 shown.

[0062] Figure 1 (a) is the steady-state photoluminescence image, Figure 1 (b) is the visible light absorption spectrum. In the visible light range, the weaker the photoluminescence intensity, the faster the migration speed of the carriers in the perovskite layer; the smaller the visible light absorption spectrum intensity, the stronger the perovskite layer's ability to absorb visible light. Figure 1 It can be seen that the photoluminescence intensity is smaller and the visible light absorption intensity is weaker with the interface modification layer under sodium alendronate, indicating that the Alds modification layer can significantly improve the optical properties of perovskite, among which the device semi-finished product prepared with a concentration of 1 mg / mL performs best.

[0063] 1.1.2 The semi-finished devices obtained in Experimental Examples 1 and 3 were tested by top and bottom scanning electron microscopes. For the bottom interface test, the top interface was glued to FTO coated with UV curable adhesive, and then the bottom interface was separated after UV curing. The results are shown in the figure. Figure 2 shown.

[0064] Figure 2 The electron microscope scanning images of Experimental Example 1 and Experimental Example 3 are shown in FIG. Figure 2 a and Figure 2 c are the electron microscope scanning images of the top and bottom of the electron transport layer of Experimental Example 1, Figure 2 b and Figure 2 d are the electron microscope scanning images of the top and bottom of the electron transport layer of Experimental Example 3. Figure 2 By comparison, it can be seen that in Experimental Example 3, sodium alendronate is used as the lower interface modification layer. Sodium alendronate can produce a chemical interaction with SnO2, which can make the surface of the SnO2 electron transport layer smoother and denser, and effectively inhibit the formation of defects in the SnO2 film; while in Experimental Example 1, there are many defects at the bottom of the electron transport layer.

[0065] 1.1.3 The semi-finished devices obtained in Experimental Example 1 and Experimental Example 3 were tested by AFM, TRPL and XRD respectively. The results were as follows: Figure 3 and Figure 4 shown.

[0066] Figure 3 For Experimental Example 1 ( Figure 3 (a) and Figure 3 (b)) and Experimental Example 3 ( Figure 3 (c) and Figure 3 (d) AFM surface topography of the SnO2 and perovskite layers. Compared to Experimental Example 1, the roughness of the perovskite and SnO2 films in Experimental Example 3 is reduced from 21.6 and 10.5 nm to 18.5 and 9.61 nm, respectively. This directly reflects the uniformity and flatness of the film formation, indicating that Alds facilitates the uniform nucleation and growth of the perovskite film, resulting in a perovskite film with larger grains and fewer defects.

[0067] Figure 4 TRPL diagrams of Experimental Example 1 and Experimental Example 3 ( Figure 4 (a)) and XRD patterns ( Figure 4 (b)). Compared with Experimental Example 1, the TRPL fluorescence lifetime in Experimental Example 3 is shorter, indicating that the Alds-modified SnO2 in Experimental Example 3 has excellent carrier transport ability, which is consistent with the Figure 1 The steady-state photoluminescence intensity of (a) is consistent, and the (001) crystal plane diffraction intensity of XRD is stronger, indicating that Alds can make the SnO2 crystal quality better.

[0068] 1.2 Interface defect passivation ability of the sodium alendronate interface modification layer

[0069] In order to verify the interface defect passivation ability of the sodium alendronate interface modification layer, the following experiment was conducted: pure Alds and FAI solutions with a concentration of 1 mg / mL and Alds-FAI and Alds-PbI2 mixed solutions with a concentration of 1 mg / mL were respectively prepared, and the above solutions were spin-coated onto FTO at 4000 rpm for 30 seconds and annealed at 100°C for 20 minutes before Fourier transform infrared transform testing. The results are shown in Figure 2. Figure 5 shown.

[0070] Figure 5 The following are the Fourier transform infrared spectroscopy test results of the interaction between Alds and the components FAI and PbI2 in the perovskite precursor solution. Figure 5 It can be seen that after adding Alds to FAI solution, FA + The amino wave number of Alds is significantly shifted, which is because the hydroxyl functional group of Alds can react with FA. + The addition of PbI2 to Alds causes the P=O bond of Alds to shift due to the interaction between the P=O bond and Pb 2+ The ions form stronger chemical bonds through Lewis acid-base interactions. This interaction effectively reduces the uncoordinated Pb in the perovskite. 2+ ions, thereby reducing the interface defect density, so the Alds modification layer can stabilize the perovskite lattice and effectively passivate the interface defects under the perovskite.

[0071] 1.3 Effect of sodium alendronate on the properties of SnO2 thin films

[0072] In order to investigate the effect of sodium alendronate on the performance of SnO2 thin films, the following experiment was conducted: pure SnO2 solution and SnO2-Alds mixed solution with a concentration of 1 mg / mL were respectively prepared and spin-coated onto FTO at 4000 rpm for 30 seconds. After the spin coating, the film was kept at 100°C for 30 minutes, then annealed at 200°C for 40 minutes, and then the photoelectron spectroscopy test was performed. The results are shown in Figure 2. Figure 6 shown.

[0073] Figure 6The following are the results of SnO2-Alds and SnO2 photoelectron spectroscopy (XPS) tests. Compared with the unmodified SnO2 film, the binding energies of Sn 3d5 / 2 and Sn 3d3 / 2 of Alds-SnO2 shifted from 486.31eV and 494.48eV to 486.24eV and 494.59eV, respectively. In the O1s XPS spectra of the SnO2 film and the Alds-SnO2 film, the peak positions shifted, indicating that the introduction of the Alds modification layer changed the distribution of oxygen atoms on the surface of the SnO2 film. The appearance of the Na 1s peak further indicates that the Alds modification layer interacts with the SnO2 film. Therefore, the Alds modification layer can interact with SnO2, improve the distribution uniformity, and inhibit the formation of oxygen vacancies.

[0074] The technical solution of this application will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0075] Example 1

[0076] A method for preparing a perovskite solar cell having an alendronate lower interface modification layer comprises the following steps:

[0077] S1. Pre-treating the conductive substrate: After scrubbing the FTO with a detergent, immerse the FTO in deionized water, 75% ethanol, and isopropanol solutions for ultrasonic cleaning for 17 minutes each; ultrasonically clean the FTO in a 10% hydrogen peroxide solution for 12 minutes, then dry it, and treat it with plasma bombardment for 15 minutes before use;

[0078] S2. 40 μL of a 1 mg / mL SnO2 solution was added to the pretreated FTO and spin-coated at 4000 rpm for 30 s. After spin-coating, the solution was kept at 100°C for 30 min and then annealed at 200°C for 40 min to prepare an electron transport layer.

[0079] S3, drop 60 μL of 1 mg / mL alendronate aqueous solution onto the electron transport layer and spin-coat 60 μL of the solution at 4000 rpm for 30 seconds, followed by annealing at 100° C. for 10 minutes to prepare the alendronate lower interface modification layer;

[0080] S4. 3.2 mg MAI, 6.8 mg FABr, 12.3 mg CsI, 16 mg MACI, 19.8 mg PbBr2, 95.2 mg FAI, and 295.6 mg PbI2 were added to a solvent consisting of 100 uL DMF and 400 uL DMSO. After the mixture was completely dissolved, a perovskite precursor solution was prepared. 45 uL of the perovskite precursor solution was spin-coated on the lower alendronate interface modification layer in multiple steps: the first stage of the spin coating was at a speed of 1000 rpm for 10 s and an acceleration of 500 rpm / s; the second stage of the spin coating was at a speed of 4000 rpm for 30 s and an acceleration of 1000 rpm / s. 200 uL of antisolvent EA was added dropwise at the 30th second. After the spin coating was completed, the mixture was annealed at 100°C for 40 min to prepare a perovskite layer.

[0081] S5. Dissolve 0.0289 g of Spiro-OMeTAD in a mixed solvent consisting of 400 μL of chlorobenzene, 7 μL of Li-TFSI acetonitrile solution (1.75-2 mol / L), and 11.4 μL of 4-tert-butylpyridine solution (0.5 mol / L), and stir for 6 hours to prepare a Spiro-OMeTAD solution. Spin-coat 45 μL of the Spiro-OMeTAD mixed solution on the perovskite layer at 4000 rpm for 30 seconds to prepare a hole transport layer.

[0082] S6. Using a vacuum evaporation machine, a metal electrode with a thickness of 100 nm is evaporated on the hole transport layer.

[0083] Comparative Example 1

[0084] This comparative example provides a method for preparing a perovskite solar cell. This method differs from Example 1 in that step S1 is different and step S3 is not included. Step S1 is as follows: a conductive substrate is pretreated: after scrubbing the FTO with a detergent, the FTO is ultrasonically cleaned in deionized water, 75% ethanol, and isopropanol for 17 minutes each, dried, and treated with plasma bombardment for 15 minutes before use. The remaining steps are identical to those in Example 1.

[0085] Comparative Example 2

[0086] This comparative example provides a method for preparing a perovskite solar cell, which differs from comparative example 1 in that step S1 is different, specifically as follows: pretreating the conductive substrate: after scrubbing the FTO with a detergent, immersing the FTO in deionized water, 75% ethanol, and isopropanol solutions for ultrasonic cleaning for 17 minutes each; placing the FTO in a 5% by mass hydrogen peroxide solution for ultrasonic cleaning for 12 minutes, drying it, and treating it with plasma bombardment for 15 minutes for later use.

[0087] Comparative Example 3

[0088] This comparative example provides a method for preparing a perovskite solar cell, which differs from comparative example 2 in that the mass fraction of the hydrogen peroxide solution in step S1 is 10%.

[0089] Comparative Example 4

[0090] This comparative example provides a method for preparing a perovskite solar cell, which differs from comparative example 2 in that the mass fraction of the hydrogen peroxide solution in step S1 is 15%.

[0091] Example 2

[0092] A method for preparing a perovskite solar cell with an alendronate lower interface modification layer is different from Example 1 in that the concentration of the alendronate aqueous solution in step S3 is 0.5 mg / mL.

[0093] Example 3

[0094] A method for preparing a perovskite solar cell with an alendronate lower interface modification layer is different from Example 1 in that the concentration of the alendronate aqueous solution in step S3 is 2 mg / mL.

[0095] 2. Photovoltaic efficiency test of perovskite solar cell devices

[0096] The photoelectric conversion efficiency (PCE) of the perovskite solar cells prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was tested. Figure 7 and Figure 8 .

[0097] Figure 7 This is a comparison chart of the PCE of devices in comparative examples 1 to 4. Figure 7 The results show that from the comparison of comparative examples 1 to 4, it can be seen that the photoelectric conversion performance of perovskite can be effectively improved after soaking in hydrogen peroxide aqueous solution of various concentrations. The reason is that hydroxyl groups are effectively introduced into the conductive substrate, and the best performance is achieved at a concentration of 10%.

[0098] Figure 8 2 is a comparison chart of the PCE of the devices of Examples 1 to 3. Figure 8 The results show that compared with comparative examples 1 to 4, the PCE values ​​of examples 1 to 3 are significantly improved, which is due to the double passivation effect of Alds at the buried interface, and the device performance is best when the Alds concentration is 1 mg / mL.

[0099] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A perovskite solar cell having an alendronate lower interface modification layer, characterized in that: The invention comprises a conductive substrate, an electron transport layer, an alendronate lower interface modification layer, a perovskite layer, a hole transport layer and a metal electrode which are stacked in sequence from bottom to top.

2. The perovskite solar cell with an alendronate lower interface modification layer according to claim 1, characterized in that: The alendronate lower interface modification layer is prepared by forming a thin film of an alendronate aqueous solution on an electron transport layer through a spin coating method and then annealing.

3. The perovskite solar cell with an alendronate lower interface modification layer according to claim 2, characterized in that: The concentration of the alendronate sodium aqueous solution is 0.5-2 mg / mL.

4. The perovskite solar cell with an alendronate lower interface modification layer according to any one of claims 1 to 3, characterized in that: The electron transport layer is a tin oxide coating.

5. The perovskite solar cell having an alendronate lower interface modification layer according to any one of claims 1 to 3, characterized in that: The tin oxide coating is prepared by forming a thin film of a SnO2 solution with a concentration of 2-4 mg / mL on a conductive substrate and then annealing the thin film.

6. The perovskite solar cell with an alendronate lower interface modification layer according to any one of claims 1 to 3, characterized in that: The molar concentration of the precursor solution of the perovskite layer is 1.5-1.6 mol / L, the solutes include MAI, FABr, CsI, MACl, PbBr2, FAI and PbI2 in a molar ratio of 1: (2.5-3): (2-2.5): (11-12.5):, (2.5-3): (25-29): (30-34), and the solvent is a mixed solution of DMF and DMSO in a volume ratio of 3:

1.

7. A method for preparing a perovskite solar cell having an alendronate lower interface modification layer according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Pre-treating the conductive substrate; S2. preparing an electron transport layer on a conductive substrate; S3, spin-coating an aqueous solution of sodium alendronate on the electron transport layer and annealing the layer to obtain a lower interface modification layer of sodium alendronate; S4, preparing a perovskite layer on the lower interface modification layer of sodium alendronate; S5. preparing a hole transport layer on the perovskite layer; S6. Vapor-depositing a metal electrode on the hole transport layer.

8. The method for preparing a perovskite solar cell having an alendronate lower interface modification layer according to claim 7, characterized in that: The step S1 specifically includes the following steps: S11, after scrubbing the conductive substrate with a detergent, the conductive substrate is placed in water for ultrasonic cleaning for 15-20 minutes; S12, placing the conductive substrate in ethanol and isopropanol for ultrasonic cleaning for 15-20 minutes; S13. Place the conductive substrate in a hydrogen peroxide solution with a mass fraction of 5-15%, ultrasonically clean it for 10-15 minutes, dry it, and then plasma clean it for 15-20 minutes.

9. The method for preparing a perovskite solar cell having an alendronate lower interface modification layer according to claim 7, characterized in that: The hole transport layer in step S5 is prepared by spin-coating a Spiro-OMeTAD solution on the perovskite layer, wherein the Spiro-OMeTAD solution is a solution in which Spiro-OMeTAD is dissolved in a mixed solvent and has a concentration of 0.05-0.08 mol / L; wherein the mixed solvent is composed of chlorobenzene, a Li-TFSI acetonitrile solution with a concentration of 1.75-2 mol / L, and a 4-tert-butylpyridine solution with a concentration of 0.4-0.6 mol / L in a volume ratio of 1:(0.015-0.02):(0.025-0.03).

10. The method for preparing a perovskite solar cell having an alendronate lower interface modification layer according to claim 7, characterized in that: The conductive substrate is FTO or ITO; the metal electrode is Ag or Au, and the thickness of the metal electrode is 100-120 nm.

Images