A buried interface defect passivated transverse perovskite solar cell and a preparation method thereof

Abstract

The application discloses a kind of interface defect passivation of buried bottom reverse perovskite solar cell and preparation method thereof, belong to solar cell technical field, the interface modification layer between the hole transport layer and perovskite light-absorbing layer of the reverse perovskite solar cell of the present application, the material of the interface modification layer is the organic compound containing hydrophobic long carbon chain, positively charged amino group and negatively charged halogen functional group simultaneously, the hydrophobic long carbon chain in the interface modification layer material of the present application can enhance stability;Positively charged amino group can passivate vacancy by occupying cubic octahedral point, fixed on the grain boundary and surface of perovskite thin film, to compensate the loss on the surface of film, passivate negative defect in perovskite by ionic bond or hydrogen bond;Negatively charged halogen functional group can slow down crystallinity in film forming process, increase the size of perovskite, can improve the photoelectric performance of perovskite thin film and the energy conversion efficiency, humidity resistance and long-term stability of device as a whole.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solar cells, and particularly relates to a buried bottom interface defect passivation inverted perovskite solar cell and a preparation method thereof. BACKGROUND

[0002] Photovoltaic power generation technology has made significant progress in cost and photoelectric conversion efficiency after years of development. As the third generation of solar cells, perovskite solar cells have attracted widespread attention due to their low cost, low-temperature preparation, and high photoelectric conversion efficiency. Compared with traditional silicon-based solar cells, perovskite solar cells not only have low material cost, but also have a simple manufacturing process, which can be prepared at low temperature, thereby reducing production costs. These advantages make perovskite solar cells have great potential in the field of renewable energy. In addition, the excellent optical and electrical properties of perovskite materials give them a significant advantage in photoelectric conversion efficiency. Studies have shown that the photoelectric conversion efficiency of perovskite solar cells has reached a level comparable to or even higher than that of traditional silicon-based cells under laboratory conditions, with single-junction perovskite solar cell efficiency exceeding 26%. With the continuous progress and optimization of related technologies, the performance and stability of perovskite solar cells will be further improved, which will pave the way for their large-scale commercialization. Under the drive of the "double carbon" goal, the development of high-efficiency, low-cost photovoltaic technology represented by perovskite solar cells will not only help reduce dependence on fossil fuels, but also significantly reduce carbon dioxide emissions and achieve sustainable development goals. Therefore, perovskite solar cells have important strategic significance and application prospects in the future development of clean energy.

[0003] The quality of perovskite solar cells depends largely on the quality of the perovskite light-absorbing layer. As a method of defect passivation, interface engineering is often used to passivate surface defect states of the perovskite light-absorbing layer, reduce non-radiative recombination of carriers, passivate defects, and improve interface contact. The buried bottom interface is more difficult to adjust than the exposed top surface of the prepared perovskite layer, but it is of great importance. Perovskite grains grow from bottom to top. A simple and feasible processing method is developed to modify the buried bottom interface of the perovskite layer to obtain a perovskite light-absorbing layer with more perfect grain growth, fewer defect states, and more uniform film formation, and better quality perovskite layer. Based on this, it is crucial to develop a buried bottom interface modification method to optimize perovskite solar cells. SUMMARY

[0004] To solve the above technical problems, the application provides a buried bottom interface defect passivated anti-type perovskite solar cell and a preparation method thereof.

[0005] To achieve the above object, the application provides the following technical scheme.

[0006] One of the technical schemes of the application is as follows:

[0007] A buried bottom interface defect passivated anti-type perovskite solar cell, wherein an interface modification layer is arranged between a hole transport layer and a perovskite light absorption layer.

[0008] The material of the interface modification layer is an organic compound containing a hydrophobic long carbon chain, a positively charged amino group and a negatively charged halogen functional group.

[0009] Preferably, the material of the interface modification layer is hexadecyl trimethyl ammonium bromide (CTAB) or hexadecyl trimethyl ammonium chloride (CTAC).

[0010] The application introduces an interface modification layer between the hole transport layer and the perovskite light absorption layer of the perovskite solar cell, which not only enhances the conductivity of the hole transport layer, but also optimizes the lower interface of the perovskite light absorption layer, improves the perovskite crystallization process, reduces the surface roughness of the perovskite light absorption layer, and reduces the interface defects, so as to effectively enhance the photoelectric performance of the solar cell device and the long-term stability.

[0011] Preferably, the buried bottom interface defect passivated anti-type perovskite solar cell comprises, from bottom to top, a transparent conductive substrate, a hole transport layer, an interface modification layer, a perovskite light absorption layer, an electron transport layer, a BCP buffer layer and a top metal electrode.

[0012] Preferably, the transparent conductive substrate comprises indium tin oxide (ITO) or fluorine-doped tin oxide (FTO); and / or

[0013] The material of the hole transport layer comprises one of MeO-2PACz ((2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl) phosphonic acid), PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid)) and Me-4PACz ([4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl] phosphonic acid); and / or

[0014] The material structure of the perovskite light absorption layer is ABX3, wherein A is CH3NH3 + (MA +NH2CH=NH2 + (FA + ) and Cs + ; B is Pb 2+ and Sn 2+ ; X is Cl - , Br - and I - ; and / or

[0015] The material of the electron transport layer is one of PCBM and fullerene (such as C 60 ).

[0016] The transparent conductive substrate has the characteristics of high conductivity, high visible light transmittance, high mechanical hardness and good chemical stability; the hole transport layer material has the characteristics of good conductivity, high light transmittance, low-temperature annealing and good energy level matching with the perovskite layer material; the perovskite light-absorbing layer material has the characteristics of large absorption coefficient, adjustable band gap, simple synthesis method and high conversion efficiency; and the electron transport material has the characteristics of suitable energy level, high electron transport capacity, simple film forming process and reduced surface charge recombination. Compared with the prior art, the interface modification organic compound is used to enhance the conductivity of the hole transport layer and modify the lower surface of the perovskite light-absorbing layer, the perovskite crystallization process is improved, the surface roughness of the perovskite light-absorbing layer is reduced, and the interface defects are passivated and reduced, so as to enhance the photoelectric performance and long-term stability of the battery device. The cell efficiency, moisture resistance and long-term stability of the trans perovskite solar cell modified by the above organic compound are all significantly higher than those of the trans perovskite solar cell without the modification of the organic compound.

[0017] Preferably, the BCP buffer layer is bathocuproin (BCP); and / or

[0018] The material of the top metal electrode is one of gold (Au), silver (Ag), copper (Cu) and aluminum (Al).

[0019] Preferably, the thickness of the transparent conductive substrate is 80-100 nm, the thickness of the hole transport layer is 10-20 nm, the thickness of the perovskite light absorption layer is 400-500 nm, the thickness of the electron transport layer is 20-40 nm, and the thickness of the top metal electrode is 80-100 nm. The transparent conductive substrate (such as ITO or FTO) needs to have high light transmittance to allow sunlight to pass through, and at the same time has good electrical conductivity to transmit current, the thickness of the substrate will affect its electrical conductivity and mechanical strength, too thick will increase the cost and reduce the light transmittance, too thin may affect the electrical conductivity and durability; the hole transport layer needs to form a good heterojunction contact interface with the perovskite light absorption layer to reduce the potential barrier in the hole transport process, the thickness of the hole transport layer will affect its electrical conductivity and the fill factor of the battery, too thick hole transport layer will increase optical and electrical losses, while too thin may lead to insufficient hole transport; the thickness of the perovskite light absorption layer directly affects the light absorption and carrier generation, increasing the thickness of the perovskite light absorption layer can enhance the absorption of incident light, but at the same time it will also increase the defects in the film, leading to increased non-radiative recombination, affecting the photoelectric conversion efficiency, therefore, a balance point needs to be found to achieve the best light absorption and carrier trapping ability; the electron transport layer needs to form an electron selective contact with the perovskite light absorption layer to improve the electron extraction efficiency and prevent holes from migrating towards the cathode, the thickness of the electron transport layer will affect the electron transport efficiency and the open-circuit voltage of the battery, too thick electron transport layer may increase the series resistance of the battery and reduce the performance; the thickness of the top metal electrode will affect its electrical conductivity and stability, too thick top metal electrode will increase the cost and block light, while too thin may affect its electrical conductivity and durability. The organic compound containing a hydrophobic long carbon chain, a positively charged amino group and a negatively charged halogen functional group is used for interface modification in the present application, which does not change the original device structure of the perovskite solar cell.

[0020] Technical solution two of the present application:

[0021] The present application also provides a preparation method of the buried bottom interface defect passivated transverse perovskite solar cell, comprising the following steps:

[0022] 1) preparing a hole transport layer on a transparent conductive substrate;

[0023] 2) preparing an interface modification layer on the hole transport layer;

[0024] 3) preparing a perovskite light absorption layer on the interface modification layer;

[0025] 4) preparing an electron transport layer on the perovskite light absorption layer;

[0026] 5) preparing a BCP buffer layer on the electron transport layer;

[0027] 6) preparing a top metal electrode on the BCP buffer layer.

[0028] Preferably, before preparing the hole transport layer on the transparent conductive substrate, the transparent conductive substrate is treated, and the specific method is as follows: the transparent conductive substrate is cleaned with a cleaning agent, dried, and subjected to ultraviolet ozone treatment.

[0029] Preferably, during the treatment of the transparent conductive substrate, the cleaning agent is at least one of deionized water, anhydrous ethanol, isopropyl alcohol (IPA), and acetone.

[0030] Preferably, in step 1), the method for preparing the hole transport layer on the transparent conductive substrate is to coat the material of the hole transport layer on the transparent conductive substrate and perform annealing treatment.

[0031] Preferably, in step 1), the annealing temperature is 100-140°C, and the time is 10-30 min.

[0032] More preferably, in step 1), the annealing temperature is 120°C, and the time is 20 min.

[0033] Preferably, in step 2), the method for preparing the interface modification layer on the hole transport layer is to dissolve the material of the interface modification layer in an organic solvent, coat it on the hole transport layer, and perform annealing treatment.

[0034] Preferably, in step 2), the annealing temperature is 50-70°C, and the time is 5-10 min.

[0035] More preferably, in step 2), the annealing temperature is 70°C, and the time is 5 min.

[0036] Preferably, in step 2), after the material of the interface modification layer is dissolved in the organic solvent, the concentration of the material of the interface modification layer in the obtained solvent is 0.4-2 mg / mL.

[0037] The organic solvent includes at least one of dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMF), isopropyl alcohol (IPA), and chlorobenzene (CB).

[0038] More preferably, in step 2), after the material of the interface modification layer is dissolved in the organic solvent, the concentration of the material of the interface modification layer in the obtained solution is 0.4 mg / mL, 0.7 mg / mL, 1 mg / mL, or 2 mg / mL.

[0039] Preferably, in step 3), the method for preparing the perovskite light-absorbing layer on the interface modification layer is: preparing a perovskite precursor solution by dissolving iodide or bromide and lead iodide in an organic solvent, spin-coating the prepared perovskite precursor solution on the interface modification layer, and performing annealing treatment; and / or

[0040] The organic solvent comprises at least one of DMSO, DMF, IPA and CB.

[0041] Preferably, in step 3), the annealing temperature is 100-120℃, and the time is 10-30min.

[0042] More preferably, in step 3), the annealing temperature is 100℃, and the time is 10min.

[0043] Preferably, in step 4), the method for preparing the electron transport layer on the perovskite light-absorbing layer is: dissolving the electron transport layer material in a solvent, and spin-coating or evaporating on the perovskite light-absorbing layer.

[0044] Preferably, in step 5), the method for preparing the BCP buffer layer on the electron transport layer is: dissolving BCP in a solvent, and spin-coating on the electron transport layer.

[0045] Preferably, in step 6), the top metal electrode is prepared on the BCP buffer layer by a vacuum evaporation method.

[0046] Preferably, the solvent in step 4) and step 5) is independently selected from one of ethanol (CH3CH2OH), isopropanol (IPA), n-butanol (CH3(CH2)3OH), chlorobenzene (CB), toluene (C7H8) and water (H2O).

[0047] The principle of the present application is:

[0048] Compared with the prior art, the present application has the following advantages and technical effects:

[0049] Compared with the existing interface modification perovskite thin film method, the present application uses an organic compound containing a hydrophobic long carbon chain, a positively charged amino group and a negatively charged halogen functional group to modify the interface between the upper surface of the hole transport layer and the lower surface of the perovskite light-absorbing layer.

[0050] The hydrophobic long carbon chain in the organic compound of the present application can enhance stability; the positively charged amino group can be fixed on the grain boundary and surface of the perovskite thin film by occupying cubic octahedral point to passivate vacancies, compensate for losses on the surface of the thin film, passivate negative defects in the perovskite through ionic bonds or hydrogen bonds; the negatively charged halogen functional group can slow down crystallinity during film formation and increase the size of the perovskite. In addition, the intervention of the negatively charged halogen functional group can modify the energy level to make the battery obtain a higher open-circuit voltage. Studies have shown that the perovskite thin film surface does not necessarily reach a thermodynamic stable state immediately after annealing. Due to the mismatch of the thermal expansion coefficient between the perovskite and the substrate, residual strain at the lower interface is generated, and when the perovskite thin film after annealing is cooled to room temperature, the lattice distortion occurs to increase the grain boundary defects, which can accelerate the degradation of the perovskite thin film, increase the non-radiative recombination, and reduce the photoelectric performance of the battery. The lattice mismatch between the perovskite and the substrate during the annealing process can cause residual stress, and the long carbon chain can improve the contact, thereby reducing the residual stress of the perovskite, which is helpful for the preparation of higher quality perovskite solar cells. Under this background, the zwitterionic structure CTAB / CTAC with positive and negative ion separation has the advantage of self-adapting to select defects with opposite charges for passivation, which is not limited by the complex composition or distribution of surface defects. In addition, the introduction of CTAB / CTAC can improve the roughness and conductivity of the hole transport layer. In summary, CTAB / CTAC plays a role in improving the perovskite light-absorbing layer and enhancing the conductivity of the hole transport layer.

[0051] The trans perovskite solar cell prepared by using the material and the preparation method of the present application improves the photoelectric performance of the perovskite thin film and the overall energy conversion efficiency, humidity resistance and long-term stability of the device.

[0052] The preparation method of the present application is simple, efficient and reliable, and has good stability, which meets the actual production needs. BRIEF DESCRIPTION OF DRAWINGS

[0053] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0054] Figure 1 The trans perovskite solar cell structure provided in Example 1 is shown in the schematic diagram, wherein 1 is a transparent conductive substrate, 2 is a hole transport layer, 3 is an interface modification layer, 4 is a perovskite light-absorbing layer, 5 is an electron transport layer, 6 is a BCP buffer layer, and 7 is a top metal electrode;

[0055] Figure 2 The structure formula of the buried bottom interface modification defect passivation material;

[0056] Figure 3J-V curve of the trans- perovskite solar cell obtained from Comparative Example 1 and Example 2;

[0057] Figure 4 SEM image of the trans- perovskite solar cell obtained from Comparative Example 1 and Example 2;

[0058] Figure 5 Water contact angle image of the hole transport layer of the trans- perovskite solar cell obtained from Comparative Example 1 and Example 2;

[0059] Figure 6 Comparison chart of long-term stability test results of the unpacked devices obtained from Comparative Example 1 and Example 5 under room temperature environment. DETAILED DESCRIPTION

[0060] Various illustrative embodiments of the present application are described in detail below. This detailed description is not intended to restrict the application unless so indicated, but merely to explain certain aspects, features and embodiments of the application.

[0061] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Additionally, the use of "including," "comprising," "having," "containing," and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless otherwise indicated, the use of the terms "or" and "and" herein is intended to indicate "inclusive or," so that "A or B" means "A, B, or both A and B." Further, unless otherwise indicated, the use of relational terms, such as "first," "second," "third," and the like, are used solely to distinguish one item from another, without necessarily giving these items any actual chronological, spatial or other order.

[0062] Unless otherwise indicated, 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. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All publications mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. In case of conflict, the content of the present specification will control.

[0063] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application.

[0064] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" or variants thereof are open-ended, and include one or more steps, integers, compositions or elements of any integer number of steps, integers, compositions or elements. It will be understood that the terms "comprise", "comprising", "include", "including", "have", "having" or variants thereof are to be construed as specifying the presence of what follows the term rather than to preclude additional, unrecited elements or steps. Where the change of an open-ended term or phrase to a

[0065] Unless otherwise specified, the room temperature in the present application is 25±2℃.

[0066] The raw materials used in the embodiments of the present application are all commercially available.

[0067] The present application provides a perovskite solar cell (see structure schematic diagram Figure 1 ), from bottom to top, including: a transparent conductive substrate 1, a hole transport layer 2, an interface modification layer 3, a perovskite light absorption layer 4, an electron transport layer 5, a BCP buffer layer 6 and a top metal electrode 7.

[0068] The structural formula of the buried bottom interface modification defect passivation material (i.e. the material of the interface modification layer) of the present application is as follows: Figure 2 .

[0069] It should be pointed out that the parts not described in detail in the present application are all conventional operation means in the art, for example, the specific methods such as spin coating, evaporation or vacuum evaporation are all completed by conventional methods.

[0070] The technical solutions of the present application are further described below through examples.

[0071] Example 1

[0072] 1) The transparent conductive substrate 1 was treated: the ITO transparent conductive electrode with a thickness of 90 nm was ultrasonically cleaned with a detergent (Tide detergent, the same below), deionized water and IPA in turn for 20 min, and then treated with ultraviolet ozone for 15 min, and then waited for subsequent use;

[0073] 2) Preparation of the hole transport layer 2: the PEDOT:PSS solution was spin-coated on the surface of the ITO substrate previously treated with ultraviolet ozone to form a uniform film, wherein the spin-coating speed was 3000 rpm, the spin-coating time was 30 s, and then annealing treatment was carried out to completely remove the remaining solution, wherein the annealing temperature was 120℃, the annealing time was 20 min, and after cooling to room temperature, it was transferred to a nitrogen-filled glove box to obtain a hole transport layer 2 with a thickness of 15 nm;

[0074] 3) Preparation of the interface modification layer 3: 50 μL of CTAB solution dissolved in IPA was uniformly added on the hole transport layer 2, wherein the solution concentration was 0.4 mg / mL (denoted as 0.4-CTAB), and then spin-coated on the hole transport layer 2 at 4000 rpm for 30 s, and then annealed at 70℃ for 5 min to remove residual solvent to obtain the interface modification layer 3;

[0075] 4) Preparation of perovskite light absorbing layer 4: 65 μΐ of MAPbI3perovskite precursor solution was prepared by dissolving 1.2 M of lead iodide (PbI2) and 1.2 M of methylammonium iodide (MAI) in a mixed solution of 900 μΐ of DMF and 100 μΐ of DMSO, and spin-coated on the interface modification layer 3 at a speed of 4000 rpm for 30 s. During the spin-coating process, 200 μΐ of CB was quickly dropped on the surface before it became turbid. Finally, the prepared film was annealed on a hot plate at a temperature of 100 °C for 10 min, and a perovskite light absorbing layer 4 with a thickness of 450 nm was obtained;

[0076] 5) Preparation of electron transport layer 5: After the device was cooled to room temperature, a PCBM solution (20 mg / mL) dissolved in CB was spin-coated on the prepared perovskite light absorbing layer 4 at a speed of 3000 rpm for 30 s, and an electron transport layer 5 with a thickness of 30 nm was obtained;

[0077] 6) Preparation of BCP buffer layer 6: A BCP solution (0.5 mg / mL) dissolved in IPA was spin-coated on the prepared electron transport layer 5 at a speed of 8000 rpm for 30 s, and a BCP buffer layer 6 was obtained;

[0078] 7) Preparation of top metal electrode 7: Ag was vacuum deposited on the prepared BCP buffer layer 6 under a pressure of 2 x 10 -4 pa to obtain a top metal electrode 7 (the thickness of the top metal electrode 7 was 100 nm), and a buried bottom interface defect passivated trans-form perovskite solar cell was obtained.

[0079] Example 2

[0080] 1) Treatment of transparent conductive substrate 1: The ITO transparent conductive electrode with a thickness of 90 nm was ultrasonically cleaned with a detergent, deionized water and IPA for 20 min, and then treated with ultraviolet ozone for 15 min for subsequent use;

[0081] 2) Preparation of hole transport layer 2: A PEDOT:PSS solution was spin-coated on the surface of the ITO transparent conductive substrate previously treated with ultraviolet ozone to form a uniform film, wherein the spin-coating speed was 3000 rpm and the spin-coating time was 30 s, and then annealed to completely remove the remaining solution, wherein the annealing temperature was 120 °C and the annealing time was 20 min. After cooling to room temperature, it was transferred to a nitrogen-filled glove box to obtain a hole transport layer 2 with a thickness of 15 nm;

[0082] 3) Preparation of interface modification layer 3: 50 μL of CTAB solution dissolved in IPA was uniformly dropped on the hole transport layer 2, wherein the solution concentration was 0.7 mg / mL (denoted as 0.7-CTAB), and then spin-coated on the hole transport layer 2 at 4000 rpm for 30 s, followed by annealing at 70 °C for 5 min to remove residual solvent, to obtain the interface modification layer 3;

[0083] 4) Preparation of perovskite light-absorbing layer 4: MAPbI3 perovskite precursor solution was prepared by dissolving 1.2 M of PbI2 and 1.2 M of MAI in a mixed solution of 900 μL of DMF and 100 μL of DMSO, 65 μL of the perovskite precursor solution was dropped on the interface modification layer 3, wherein the spin-coating speed was 4000 rpm and the spin-coating time was 30 s, 200 μL of CB was quickly dropped during the spin-coating process before the surface became turbid, and finally the prepared film was placed on a hot plate for annealing treatment, wherein the annealing temperature was 100 °C and the annealing time was 10 min, to obtain a perovskite light-absorbing layer 4 with a thickness of 450 nm;

[0084] 5) Preparation of electron transport layer 5: after the device was cooled to room temperature, PCBM solution (20 mg / mL) dissolved in CB was spin-coated on the prepared perovskite light-absorbing layer 4 at a speed of 3000 rpm, and the spin-coating time was 30 s, to obtain an electron transport layer 5 with a thickness of 30 nm;

[0085] 6) Preparation of BCP buffer layer 6: BCP solution (0.5 mg / mL) dissolved in IPA was spin-coated on the prepared electron transport layer 5 at a speed of 8000 rpm, and the spin-coating time was 30 s, to obtain a BCP buffer layer 6;

[0086] 7) Preparation of top metal electrode 7: Ag was vacuum deposited on the prepared BCP buffer layer 6 under a pressure of 2 x 10 -4 pa, to obtain a top metal electrode 7 (the thickness of the top metal electrode 7 was 100 nm), thereby obtaining a buried bottom interface defect passivated trans-form perovskite solar cell.

[0087] Example 3

[0088] 1) Treatment of transparent conductive substrate 1: the ITO transparent conductive electrode with a thickness of 90 nm was ultrasonically cleaned with detergent, deionized water and isopropyl alcohol (IPA) for 20 min, and then treated with ultraviolet ozone for 15 min, and then waited for subsequent use;

[0089] 2) Preparation of hole transport layer 2: spin-coat PEDOT:PSS solution on the surface of pre-UV-ozone treated ITO transparent conductive substrate to form a uniform film, wherein the spin-coating speed is 3000 rpm, the spin-coating time is 30 s, and then annealing treatment is performed to completely remove the remaining solution, wherein the annealing temperature is 120 °C, the annealing time is 20 min, and after cooling to room temperature, it is transferred to a nitrogen-filled glove box to obtain a hole transport layer 2 with a thickness of 15 nm;

[0090] 3) Preparation of interface modification layer 3: uniformly drop 50 μL of CTAB solution dissolved in IPA on the hole transport layer 2, wherein the solution concentration is 1 mg / mL (denoted as 1-CTAB), and then spin-coat on the hole transport layer 2 at 4000 rpm for 30 s, and then anneal at 70 °C for 5 min to remove residual solvent to obtain interface modification layer 3;

[0091] 4) Preparation of perovskite light-absorbing layer 4: prepare a MAPbI3 perovskite precursor solution by dissolving 1.2 M of PbI2 and 1.2 M of MAI in a mixed solution of 900 μL of DMF and 100 μL of DMSO, drop 65 μL of perovskite precursor solution on the interface modification layer 3, wherein the spin-coating speed is 4000 rpm, the spin-coating time is 30 s, and during the spin-coating process, 200 μL of CB is quickly dropped before the surface becomes turbid, and finally the prepared thin film is placed on a hot plate for annealing treatment, wherein the annealing temperature is 100 °C, the annealing time is 10 min, to obtain a perovskite light-absorbing layer 4 with a thickness of 450 nm;

[0092] 5) Preparation of electron transport layer 5: after the device is cooled to room temperature, spin-coat PCBM solution (20 mg / mL) dissolved in CB on the prepared perovskite light-absorbing layer 4 at a speed of 3000 rpm, and the spin-coating time is 30 s, to obtain an electron transport layer 5 with a thickness of 30 nm;

[0093] 6) Preparation of BCP buffer layer 6: spin-coat BCP solution (0.5 mg / mL) dissolved in IPA on the prepared electron transport layer 5 at a speed of 8000 rpm, and the spin-coating time is 30 s, to obtain a BCP buffer layer 6;

[0094] 7) Preparation of top metal electrode 7: vacuum deposit Ag on the prepared BCP buffer layer 6 under a pressure of 2 x 10 -4 Pa to obtain a top metal electrode 7 (the thickness of the top metal electrode 7 is 100 nm), to obtain a buried bottom interface defect passivated transverse perovskite solar cell.

[0095] Example 4

[0096] 1) Treatment of transparent conductive substrate 1: ITO transparent conductive electrode with thickness of 100 nm was cleaned by ultrasonic washing with detergent, anhydrous ethanol and acetone successively for 20 min, followed by ozone treatment for 15 min, and waiting for subsequent use;

[0097] 2) Preparation of hole transport layer 2: In a nitrogen-filled glove box, MeO-2PACz solution (2 mg / mL MeO-2PACz dissolved in anhydrous ethanol) was spin-coated on the surface of ITO transparent conductive substrate pre-treated by UV-ozone, to form a uniform film, wherein the spin-coating speed was 4000 rpm, the spin-coating time was 30 s, followed by annealing treatment to completely remove the residual anhydrous ethanol, wherein the annealing temperature was 100°C, the annealing time was 10 min, and after cooling to room temperature, the hole transport layer 2 with a thickness of 10 nm was obtained;

[0098] 3) Preparation of interface modification layer 3: 50 μL of CTAC solution dissolved in IPA was uniformly added on the hole transport layer 2, wherein the solution concentration was 2 mg / mL, followed by spin-coating on the hole transport layer 2 at 4000 rpm for 30 s, followed by annealing at 70°C for 3 min to remove residual solvent, to obtain the interface modification layer 3;

[0099] 4) Preparation of perovskite light-absorbing layer 4: 1.2 M of PbI2 and 1.2 M of MAI were dissolved in a mixed solution of 900 μL of IPA and 100 μL of CB to prepare a MAPbI3 perovskite precursor solution, 50 μL of the perovskite precursor solution was spin-coated on the interface modification layer 3, wherein the spin-coating speed was 3500 rpm, and the spin-coating time was 30 s. During the spin-coating (i.e. spin-coating), 200 μL of CB was quickly added before the surface became turbid, and finally the prepared film was placed on a hot plate for annealing treatment, wherein the annealing temperature was 110°C, and the annealing time was 10 min, to obtain the perovskite light-absorbing layer 4 with a thickness of 500 nm;

[0100] 5) Preparation of electron transport layer 5: After the device was cooled to room temperature, PCBM solution (20 mg / mL) dissolved in CB was spin-coated on the prepared perovskite light-absorbing layer 4 at a speed of 4000 rpm, and the spin-coating time was 30 s, to obtain the electron transport layer 5 with a thickness of 20 nm;

[0101] 6) Preparation of BCP buffer layer 6: BCP solution (0.5 mg / mL) dissolved in CH3CH2OH was spin-coated on the prepared electron transport layer 5 at a speed of 8000 rpm, and the spin-coating time was 30 s, to obtain the BCP buffer layer 6;

[0102] 7) Preparation of top metal electrode 7: 2×10 -4Under the pressure of pa, Au was vacuum deposited on the prepared BCP buffer layer 6 to obtain a top metal electrode 7 (the thickness of the top metal electrode 7 is 100 nm), thereby obtaining an inverted perovskite solar cell with buried bottom interface defect passivation.

[0103] Example 5

[0104] 1) Treatment of the transparent conductive substrate 1: The FTO transparent conductive electrode with a thickness of 80 nm was ultrasonically cleaned for 20 min using a detergent, anhydrous ethanol and acetone in turn, and then treated with ultraviolet ozone for 15 min, and then waited for subsequent use;

[0105] 2) Preparation of the hole transport layer 2: In a nitrogen-filled glove box, a Me-4PACz solution (2 mg / mL Me-4PACz dissolved in anhydrous ethanol) was spin-coated on the surface of the FTO transparent conductive substrate previously treated with ultraviolet ozone to form a uniform film, wherein the spin-coating speed was 4000 rpm, the spin-coating time was 30 s, and then annealing treatment was performed to completely remove the remaining anhydrous ethanol, wherein the annealing temperature was 100°C, the annealing time was 10 min, and after cooling to room temperature, the hole transport layer 2 with a thickness of 15 nm was obtained;

[0106] 3) Preparation of the interface modification layer 3: 50 μL of a CTAC solution dissolved in IPA was uniformly added to the hole transport layer 2, wherein the solution concentration was 2 mg / mL, and then spin-coated on the hole transport layer 2 at 4000 rpm for 30 s, and then annealed at 70°C for 3 min to remove residual solvents, thereby obtaining the interface modification layer 3;

[0107] 4) Preparation of the perovskite light-absorbing layer 4: 1.2M of PbI2 and 1.2M of MAI were dissolved in a mixed solution of 900 μL of DMF and 100 μL of DMSO to prepare a MAPbI3 perovskite precursor solution, and 50 μL of the perovskite precursor solution was spin-coated on the interface modification layer 3, wherein the spin-coating speed was 3500 rpm, and the spin-coating time was 30 s. During the spin-coating (i.e. spin-coating), 200 μL of CB was quickly added before the surface became turbid, and finally the prepared thin film was placed on a hot plate for annealing treatment, wherein the annealing temperature was 100°C, and the annealing time was 10 min, thereby obtaining the perovskite light-absorbing layer 4 with a thickness of 500 nm;

[0108] 5) Preparation of the electron transport layer 5: After the device was cooled to room temperature, C 60 60 solution (20 mg / mL) dissolved in CB was spin-coated on the prepared perovskite light-absorbing layer 4 at a speed of 4000 rpm, and the spin-coating time was 30 s, thereby obtaining the electron transport layer 5 with a thickness of 20 nm;

[0109] 6) Preparation of BCP buffer layer 6: BCP solution (0.5 mg / mL) dissolved in CB was spin-coated on the prepared electron transport layer 5 at a speed of 8000 rpm for 30 s to obtain the BCP buffer layer 6;

[0110] 7) Preparation of top metal electrode 7: The top metal electrode 7 Cu was vacuum deposited on the prepared BCP buffer layer 6 (the thickness of the top metal electrode 7 was 100 nm) under a pressure of 2 x 10 -4

[0111] Example 6

[0112] 1) Preparation of transparent conductive substrate 1: The ITO transparent conductive electrode with a thickness of 80 nm was ultrasonically cleaned with detergent, deionized water and IPA in turn for 20 min, and then treated with ultraviolet ozone for 15 min, and then waited for subsequent use;

[0113] 2) Preparation of hole transport layer 2: PEDOT:PSS solution was spin-coated on the surface of the ITO transparent conductive substrate previously treated with ultraviolet ozone to form a uniform film, wherein the spin-coating speed was 2500 rpm and the spin-coating time was 30 s, and then annealing treatment was performed to completely remove the remaining solution, wherein the annealing temperature was 100°C and the annealing time was 30 min, and after cooling to room temperature, it was transferred to a nitrogen-filled glove box to obtain a hole transport layer 2 with a thickness of 20 nm;

[0114] 3) Preparation of interface modification layer 3: 50 μL of CTAB solution dissolved in IPA was uniformly added to the hole transport layer 2, wherein the solution concentration was 1 mg / mL (denoted as 1-CTAB), and then spin-coated on the hole transport layer 2 at 4000 rpm for 30 s, and then annealed at 50°C for 10 min to remove residual solvent to obtain the interface modification layer 3;

[0115] 4) Preparation of perovskite light-absorbing layer 4: 1.2 M SnI2 (tin iodide) and 1.2 M MAI were dissolved in a mixed solution of 900 μL DMF and 100 μL DMSO to prepare a MASnI3 perovskite precursor solution, and 65 μL of the perovskite precursor solution was dropped on the interface modification layer 3, wherein the spin-coating speed was 3500 rpm and the spin-coating time was 30 s, and during the spin-coating process, 200 μL of CB was quickly added before the surface became turbid, and finally the prepared film was placed on a hot plate for annealing treatment, wherein the annealing temperature was 120°C and the annealing time was 10 min, to obtain a perovskite light-absorbing layer 4 with a thickness of 500 nm;

[0116] ​5) Preparation of electron transport layer 5: After the device is cooled to room temperature, a PCBM solution (20 mg / mL) dissolved in CB is spin-coated on the prepared perovskite light-absorbing layer 4 at a speed of 2000 rpm, and the spin-coating time is 30 s, to obtain an electron transport layer 5 with a thickness of 40 nm;

[0117] 6) Preparation of BCP buffer layer 6: A BCP solution (0.5 mg / mL) dissolved in IPA is spin-coated on the prepared electron transport layer 5 at a speed of 8000 rpm, and the spin-coating time is 30 s, to obtain a BCP buffer layer 6;

[0118] 7) Preparation of top metal electrode 7: Ag is vacuum-deposited on the prepared BCP buffer layer 6 under a pressure of 2 x 10 -4 pa, to obtain a top metal electrode 7 (the thickness of the top metal electrode 7 is 80 nm), thereby obtaining a bottom-embedded interface defect passivated trans- perovskite solar cell.

[0119] Example 7

[0120] 1) Preparation of transparent conductive substrate 1: The ITO transparent conductive electrode with a thickness of 90 nm is ultrasonically cleaned with a detergent, deionized water and IPA for 20 min, and then treated with ultraviolet ozone for 15 min, and then left for subsequent use;

[0121] 2) Preparation of hole transport layer 2: A PEDOT:PSS solution is spin-coated on the surface of the ITO transparent conductive substrate previously treated with ultraviolet ozone to form a uniform film, wherein the spin-coating speed is 4500 rpm, and the spin-coating time is 30 s, and then annealing treatment is performed to completely remove the remaining solution, wherein the annealing temperature is 140°C, and the annealing time is 10 min, and after cooling to room temperature, it is transferred to a nitrogen-filled glove box, to obtain a hole transport layer 2 with a thickness of 10 nm;

[0122] 3) Preparation of interface modification layer 3: 50 μL of CTAB solution dissolved in IPA is uniformly dropped on the hole transport layer 2, wherein the solution concentration is 1 mg / mL (denoted as 1-CTAB), and then spin-coated on the hole transport layer 2 at 4000 rpm for 30 s, and then annealed at 60°C for 8 min to remove residual solvent, to obtain an interface modification layer 3;

[0123] 4) Preparation of perovskite light-absorbing layer 4: FAI (formamidinium hydroiodide) 260.02 mg, MACI (methylammonium chloride) 5.72 mg, MABr (potassium-based ammonium bromide) 8.22 mg, Csl (cesium iodide) 15.59 mg, PbI2(lead iodide) 497.89 mg, PbCl2(lead chloride) 16.69 mg, PbBr2(lead bromide) 22.02 mg were weighed into a mixed solution of 900 μL DMF and 100 μL DMSO to prepare a FA 0.90 MA 0.05 CS 0.05 Pb(I 0.90 Cl 0.05 Br 0.05 )3 perovskite precursor solution, 65 μL of the perovskite precursor solution was dropped on the interface modification layer 3, wherein the spin coating speed was 4500 rpm and the spin coating time was 30 s, 200 μL of CB was quickly dropped during the spin coating process before the surface became turbid, and finally the prepared film was placed on a hot plate for annealing treatment, wherein the annealing temperature was 100°C and the annealing time was 30 min, to obtain a perovskite light-absorbing layer 4 with a thickness of 400 nm;

[0124] 5) Preparation of electron transport layer 5: after the device was cooled to room temperature, a PCBM solution (20 mg / mL) dissolved in CB was spin-coated on the prepared perovskite light-absorbing layer 4 at a speed of 4000 rpm, and the spin coating time was 30 s, to obtain an electron transport layer 5 with a thickness of 20 nm;

[0125] 6) Preparation of BCP buffer layer 6: a BCP solution (0.5 mg / mL) dissolved in IPA was spin-coated on the prepared electron transport layer 5 at a speed of 8000 rpm, and the spin coating time was 30 s, to obtain a BCP buffer layer 6;

[0126] 7) Preparation of top metal electrode 7: Al was vacuum deposited on the prepared BCP buffer layer 6 under a pressure of 2 x 10 -4 Pa to obtain a top metal electrode 7 (the thickness of the top metal electrode 7 was 100 nm), thereby obtaining a buried bottom interface defect passivated trans-form perovskite solar cell.

[0127] Comparative Example 1: No interface modification layer between hole transport layer and perovskite light-absorbing layer

[0128] The structure of the trans-form perovskite solar cell of this comparative example was the same as that of Example 2, except that there was no interface modification layer between the hole transport layer and the perovskite light-absorbing layer, and the preparation method was as follows:

[0129] 1) Treatment of transparent conductive substrate 1: ITO transparent conductive electrode with a thickness of 90 nm was cleaned by ultrasonic cleaning with cleaning agent, deionized water and IPA for 20 min, followed by UV ozone treatment for 15 min, and then waiting for subsequent use;

[0130] 2) Preparation of hole transport layer 2: PEDOT:PSS solution was spin-coated on the surface of the ITO substrate pre-treated by ozone to form a uniform film, wherein the spin-coating speed was 3000 rpm, the spin-coating time was 30 s, and then annealing treatment was performed to completely remove the remaining solution, wherein the annealing temperature was 120°C, and the annealing time was 20 min. After cooling to room temperature, it was transferred to a nitrogen-filled glove box to obtain a hole transport layer 2 with a thickness of 15 nm;

[0131] 3) 50 μL of IPA was dispersed on the hole transport layer 2, followed by spin coating at a speed of 4000 rpm for 30 s, and finally annealing treatment was performed to remove the residual solvent, wherein the annealing temperature was 70°C, and the annealing time was 5 min;

[0132] 4) Preparation of perovskite light-absorbing layer 4: MAPbI3 perovskite precursor solution was prepared by dissolving 1.2 M of PbI2 and 1.2 M of MAI in a mixed solution of 900 μL of DMF and 100 mL of DMSO, 65 μL of the perovskite precursor solution was dropped on the product obtained in step 3), wherein the spin-coating speed was 4000 rpm, the spin-coating time was 30 s, and during the spin-coating process, 200 μL of CB was quickly dropped before the surface became turbid, and finally the prepared thin film was placed on a hot plate for annealing treatment, wherein the annealing temperature was 100°C, and the annealing time was 10 min, to obtain a perovskite light-absorbing layer 4 with a thickness of 450 nm;

[0133] 5) Preparation of electron transport layer 5: After the device was cooled to room temperature, PCBM solution (20 mg / mL) dissolved in CB was spin-coated on the prepared perovskite layer 4 at a speed of 3000 rpm for 30 s to obtain an electron transport layer 5 with a thickness of 30 nm;

[0134] 6) Preparation of BCP buffer layer 6: BCP solution (0.5 mg / mL) dissolved in IPA was spin-coated on the prepared electron transport layer 5 at a speed of 8000 rpm for 30 s to obtain a BCP buffer layer 6;

[0135] 7) Preparation of top metal electrode 7: Ag was vacuum deposited on the prepared BCP buffer layer 6 under a pressure of 2 x 10 -4 Pa to obtain a top metal electrode 7 (the thickness of the top metal electrode 7 was 100 nm), thereby obtaining a trans-perovskite solar cell.

[0136] Performance test

[0137] The photoelectric conversion performance of the perovskite solar cells obtained in Comparative Example 1 and Examples 1-7 under sunlight irradiation was tested (according to GB / T 34160-2017), and the results are shown in Table 1.

[0138] Table 1. Performance parameters of perovskite solar cells corresponding to comparative examples and embodiments.

[0139]

[0140]

[0141] The JV curves of the inverted perovskite solar cells obtained in Comparative Example 1 and Example 2 are shown in the figure. Figure 3 Through Table 1 and Figure 3 It can be seen that the J values ​​of each device after optimization using CTAB and CTAC are... SC and V OC All achieved varying degrees of improvement, with a significant increase in PCE. Among them, the 0.7-CTAB, as a champion device, showed J... SC Increased to 22.50 mA / cm 2 V OC With an increase to 0.95V, the FF is 81.12%, and the optimal PCE is 17.30%.

[0142] SEM images of the inverted perovskite solar cells obtained in Comparative Example 1 and Example 2 are shown below. Figure 4 It can be understood that the present invention uses interface-modified organic compounds to enhance the conductivity of the hole transport layer and modify the lower surface of the perovskite light-absorbing layer, which can improve the perovskite crystallization process, reduce the surface roughness of the perovskite light-absorbing layer, and passivate and reduce interface defects, so as to enhance the photoelectric performance and long-term stability of the battery device.

[0143] Images of the water contact angle of the hole transport layer in the inverse perovskite solar cells obtained in Comparative Example 1 and Example 2 are shown below. Figure 5 As can be seen, the water contact angle of the hole transport layer after CTAB modification is significantly increased, and its hydrophobicity is enhanced. Therefore, the enhanced hydrophobicity facilitates the nucleation and growth of perovskite thin films, promotes overall performance improvement, and also inhibits the corrosive effect of water vapor on the device.

[0144] The unpackaged devices obtained in Comparative Example 1 and Example 2 were placed in an indoor environment with a humidity of 60-70% RH and a temperature of 25°C. Efficiency tests were performed every 50 hours, and normalized graphs were plotted. A comparison of the long-term stability test results of the unpackaged devices obtained in Comparative Example 1 and Example 2 at room temperature is shown in the graph. Figure 6It can be seen that the CTAC modified device shows enhanced stability under 60-70% RH and 25°C, maintaining 80% of the initial efficiency after 400 h storage, indicating an improvement in the long-term stability of the battery device.

[0145] The above merely provides the preferred embodiment of the present application, and the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for fabricating an inverted perovskite solar cell with passivated underlying interface defects, characterized in that, Includes the following steps: 1) Fabrication of a hole transport layer on a transparent conductive substrate; 2) An interface modification layer is prepared on the hole transport layer; 3) A perovskite light-absorbing layer is prepared on the interface modification layer; 4) An electron transport layer is prepared on the perovskite light-absorbing layer; 5) Prepare a BCP buffer layer on the electron transport layer; 6) Fabricate a top metal electrode on the BCP buffer layer; An interface modification layer is present between the upper surface of the hole transport layer and the lower surface of the perovskite light-absorbing layer in the inverted perovskite solar cell with buried interface defect passivation. The material of the interface modification layer is hexadecyltrimethylammonium bromide or hexadecyltrimethylammonium chloride; The inverted perovskite solar cell with buried interface defect passivation includes, from bottom to top: a transparent conductive substrate, a hole transport layer, an interface modification layer, a perovskite light-absorbing layer, an electron transport layer, a BCP buffer layer, and a top metal electrode. The thickness of the transparent conductive substrate is 80-100 nm, the thickness of the hole transport layer is 10-20 nm, the thickness of the perovskite light-absorbing layer is 400-500 nm, the thickness of the electron transport layer is 20-40 nm, and the thickness of the top metal electrode is 80-100 nm. The method for preparing the interface modification layer on the hole transport layer is as follows: dissolving the material of the interface modification layer in an organic solvent, coating it on the hole transport layer, and then performing an annealing treatment. After the material of the interface modification layer is dissolved in an organic solvent, the concentration of the material of the interface modification layer in the resulting solution is 0.7 mg / mL; The transparent conductive substrate includes indium tin oxide or fluorine-doped tin oxide; The hole transport layer is made of one of MeO-2PACz, PEDOT:PSS and Me-4PACz. The perovskite light-absorbing layer has a material structure of ABX3, where A is CH3NH3. + NH2CH=NH2 + and Cs + One of them; B is Pb 2+ and Sn 2+ One of them; X is Cl - ,Br - and I - One of them; The electron transport layer is made of either PCBM or fullerene. The BCP buffer layer is copper bath solution; The material of the top metal electrode is one of gold, silver, copper and aluminum.

2. The method for fabricating an inverted perovskite solar cell with buried interface defect passivation according to claim 1, characterized in that, In step 1), the method for preparing the hole transport layer on the transparent conductive substrate is as follows: the material of the hole transport layer is coated on the transparent conductive substrate and then annealed.

3. The method for fabricating an inverse perovskite solar cell with buried interface defect passivation according to claim 1, characterized in that, In step 2), the organic solvent includes one of dimethyl sulfoxide, N,N-dimethylacetamide, isopropanol, and chlorobenzene.

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