Application of calixarene supermolecule in preparation of perovskite solar cell

Abstract

The invention discloses an application of calixarene supramolecules in preparation of a perovskite solar cell, and belongs to the technical field of perovskite solar cells. According to the invention, calixarene supermolecules are doped with a hole transport layer (HTL), and the calixarene supermolecules have a unique cavity structure and rich hydroxyl groups, can synchronously fix I-, CH (NH2) 2 +, Li + and Ag, improve the extraction and migration efficiency of holes, passivate the defects of a perovskite / HTL interface in situ, stabilize functional layers such as a metal electrode layer, HTL and a perovskite light absorption layer, and improve the photoelectric conversion efficiency. Therefore, the long-term operation stability of the device is remarkably improved, the controllable preparation of the efficient and stable perovskite solar cell is realized, and a foundation is laid for the commercial application of the perovskite photovoltaic technology.

Description

Technical Field

[0001] The invention relates to application of calixarene supramolecule in preparing perovskite solar cells, belonging to the technical field of preparation of perovskite solar cells. Background Art

[0002] Perovskite solar cells (PSCs) are one of the new solar cells with the greatest potential for commercial application due to their advantages such as low cost, high efficiency, and solution processing. They are also the fastest growing photovoltaic technology. At present, perovskite solar cells have achieved a certified power conversion efficiency (PCE) of 26.7%. Compared with the rapid development of PCE, the research on the working stability of devices is relatively lagging behind. The long-term operating stability of batteries is the main obstacle to the large-scale commercial application of perovskite photovoltaic technology. The intrinsic instability of ion migration and metal electrode diffusion is the biggest challenge to achieving long-term stable operation of devices.

[0003] Highly efficient inverse PSCs usually rely on 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) doped with lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) and 4-tert-butylpyridine (tBP) as an organic hole transport layer (HTL). + Due to their small size, they are very easy to migrate and diffuse. Moreover, the organic cations (CH(NH2)2 + / CH3NH3 + ) is volatile, causing the collapse and disintegration of the perovskite crystal structure. In addition, halogen ions also have the property of migration. Under the action of light or heat stress, the metal electrode (Ag / Au) will also diffuse and undergo irreversible chemical reactions with the halogen ions, seriously damaging the performance and stability of the perovskite light absorption layer, HTL and metal electrode layer. However, there are no related reports that can simultaneously solve the problems of I-, CH(NH2)2 + , Li + Due to the migration and diffusion problems of Ag (Au), it is necessary to develop effective co-dopants to simultaneously fix I - 、CH(NH2)2 + , Li + and Ag(Au) to simultaneously stabilize the perovskite light absorption layer, HTL, and metal electrode layer, thereby further improving the efficiency and long-term operation stability of perovskite solar cells. Summary of the invention

[0004] In order to solve the existing perovskite solar cells - 、CH(NH2)2 + , Li +The invention aims to solve the migration and diffusion problems of Ag (Au), and to provide an application of a calixarene supramolecule in the preparation of a perovskite solar cell. When preparing the perovskite solar cell, the calixarene supramolecule is doped in the hole transport layer of the cell.

[0005] Preferably, the structural formula of the calixarene supramolecule is as shown in Formula I, Formula II and Formula III, wherein Formula I is C4A, Formula II is C6A, and Formula III is C8A;

[0006]

[0007] Preferably, the preparation method of the hole transport layer is: adding 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene and calixarene supramolecules to chlorobenzene and mixing them evenly to obtain a mixed solution, mixing the mixed solution, 4-tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide solution to obtain a hole transport layer solution, and spin coating the hole transport layer solution on the perovskite light absorbing layer to form a hole transport layer.

[0008] Preferably, the amount of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene added to chlorobenzene is 70-75 mg / mL, and the amount of calixarene supramolecule added is 0.01-5.00 mg / mL; the volume ratio of the mixed solution, 4-tert-butylpyridine (tBP) and lithium bistrifluoromethanesulfonyl imide (Li-TFSI) solution is 1:(25-35):(15-25).

[0009] Preferably, the preparation method of the perovskite solar cell is as follows:

[0010] (1) Spin coating an electron transport layer solution on a pre-treated conductive substrate, and after annealing, performing ultraviolet ozone irradiation treatment or plasma treatment to form an electron transport layer on the conductive substrate.

[0011] (2) Spin-coating the perovskite precursor solution on the electron transport layer in step (1), dropping an anti-solvent, and performing annealing to form a perovskite light absorbing layer on the electron transport layer.

[0012] (3) Spin coating the hole transport layer solution on the perovskite light absorbing layer in step (2) to form a hole transport layer on the perovskite light absorbing layer.

[0013] (4) Prepare a metal back electrode on the hole transport layer described in step (3).

[0014] Preferably, the material of the conductive substrate layer in step (1) is any one of ITO and FTO; the pretreatment is: the material of the conductive substrate layer is ultrasonically cleaned with detergent, deionized water, acetone, and anhydrous ethanol in sequence, then dried with nitrogen, and treated with ultraviolet ozone for 10 to 50 minutes.

[0015] Preferably, in step (1), the electron transport layer is one or more of SnO2, TiO2, ZnO, BaSnO3 or CeO2, or a mixture of them in any proportion; the ultraviolet ozone irradiation treatment or plasma treatment time is 20 to 100 minutes.

[0016] Preferably, in step (2), the perovskite light absorbing layer is ABX3, wherein A is CH3NH3 + or CH(NH2)2 + , B is Cs + , Rb + , Pb 2+ Sn 2+ Or Ge 2+ One of the following, X is Cl - Br - or I - The anti-solvent is any one of chlorobenzene, dichloromethane, dichlorobenzene, toluene, ethyl acetate, chloroform or ether or a mixture of them in any proportion.

[0017] Preferably, the metal back electrode in step (4) is any one of Au, Ag or a low-temperature carbon electrode.

[0018] Preferably, the spin coating conditions in all steps are a rotation speed of 2500-6500 rpm and a time of 20-60 s; and the annealing temperature in all steps is 80-150° C. and a time of 5-30 min.

[0019] Beneficial effects of the present invention

[0020] (1) The present invention discloses the application of calixarene supramolecules in perovskite solar cells, mainly using calixarene supramolecules to prepare the hole transport layer of the perovskite solar cell, and simultaneously regulating the HTL, the perovskite / HTL interface and the HTL / metal electrode interface to synchronously fix I - 、CH(NH2)2 + , Li + and Ag / Au, thereby stabilizing the perovskite light absorption layer, HTL and metal electrode layer at the same time, to significantly improve the long-term operation stability of the device.

[0021] (2) The present invention achieves an improvement in the power conversion efficiency (PCE) of the cell by co-doping the hole transport layer of the perovskite solar cell with a calixarene supramolecule, wherein the power conversion efficiency (PCE) of the cell prepared by the one-step method is improved from 22.05% to 25.30%, and the power conversion efficiency (PCE) of the cell prepared by the two-step method is improved from 24.48% to 25.27%.

[0022] (3) The battery prepared based on the one-step method showed a T90 life of 780 hours under continuous operation, and maintained an initial efficiency of more than 91.00% after aging for 1800 hours at 65°C in a nitrogen glove box, and maintained an initial efficiency of more than 90.00% after aging for 2800 hours under a relative humidity of 25% to 35%.

[0023] (4) The present invention improves the photoelectric conversion efficiency and long-term operating stability of the battery by co-doping the hole transport layer of the perovskite solar cell with calixarene supramolecules.

[0024] (5) The HTL co-doping method based on calixarene supramolecules in the present invention has simple process, good repeatability and universality, and is of great significance in promoting the industrialization process of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The calixarene supramolecular C8A, C6A and C4A in Examples 1 to 4 are respectively reacted with Li + Theoretical calculation of the chemical interaction between Ag and the perovskite surface.

[0026] Figure 2 The NMR spectrum of the calixarene supramolecular C8A interacting with Li-TFSI in Example 1 7 Li NMR and 1 H NMR.

[0027] Figure 3 The XPS spectra of N1s and I 3d of the perovskite light absorbing layer not coated with the calixarene supramolecule C8A in Comparative Example 1 and the perovskite light absorbing layer coated with the calixarene supramolecule C8A in Example 1.

[0028] Figure 4 TOF-SIMS spectra of the battery without calixarene supramolecule C8A doped in Comparative Example 1 and the battery with calixarene supramolecule C8A doped in Example 1.

[0029] Figure 5 These are cross-sectional SEM images of the battery without calixarene supramolecule C8A doped in Comparative Example 1 and the battery with calixarene supramolecule C8A doped in Example 1.

[0030] Figure 6 This is a high-resolution mass spectrum of the interaction between the calixarene supramolecule C8A and Li-TFSI in Example 1.

[0031] Figure 7 Schematic diagram of the doping mechanism of the calixarene supramolecule C8A on HTL in Example 1.

[0032] Figure 8 ESR spectra of the hole transport layer of pure Spiro (Spiro), the hole transport layer doped with calixarene supramolecular C8A (Spiro-C8A), the hole transport layer doped with Li-TFSI and tBP (Spiro@Li), and the hole transport layer doped with Li-TFSI, tBP and calixarene supramolecular C8A (Spiro@Li-C8A) in Example 1.

[0033] Fig. 9 The electrical conductivity of the hole transport layer of pure Spiro (Spiro), the hole transport layer doped with calixarene supramolecular C8A (Spiro-C8A), the hole transport layer doped with Li-TFSI and tBP (Spiro@Li), and the hole transport layer doped with Li-TFSI, tBP and calixarene supramolecular C8A (Spiro@Li-C8A) in Example 1.

[0034] Fig.10 The XPS Pb 4f spectra of the perovskite light-absorbing layer of Comparative Example 1 not coated with the calixarene supramolecule C8A and the silver electrode layer coated with the calixarene supramolecule C8A in Example 1 are shown.

[0035] Fig.11 It is a dark state IV curve diagram of the ITO / PTAA / Spiro-OMeTAD@Li-TFSI / Ag perovskite structure device without calixarene supramolecule C8A in comparative example 1 and the ITO / PTAA / Spiro-OMeTAD@Li-TFSI-C8A / Ag doped with calixarene supramolecule C8A in example 1.

[0036] Fig.12 1 and 2 are current density-voltage curves of the perovskite solar cells prepared by the method in Comparative Example 1 and Example 1.

[0037] Fig.13 2 are the current density-voltage curves of the perovskite solar cells prepared in Comparative Example 1 and Example 2.

[0038] Fig.14 These are the MPP stability test results of the unencapsulated perovskite solar cells in Comparative Example 1 and Example 1.

[0039] Fig.15These are the thermal stability test results of the unencapsulated perovskite solar cells in Comparative Example 1 and Example 1.

[0040] Fig.16 These are the humidity stability test results of the unencapsulated perovskite solar cells in Comparative Example 1 and Example 1.

[0041] Fig.17 1 and 2 are current density-voltage curves of the perovskite solar cells prepared by the one-step method in Comparative Example 1 and Implementation Example 3.

[0042] Fig.18 1 and 2 are current density-voltage curves of the perovskite solar cells prepared by the one-step method in Comparative Example 1 and Implementation Example 4. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0044] Example 1

[0045] A method for preparing a perovskite solar cell. In this embodiment, a one-step method is used to prepare a perovskite light-absorbing layer. The specific preparation method includes the following steps:

[0046] (1) The ITO conductive substrate was cleaned with detergent, deionized water, acetone, and anhydrous ethanol in sequence, then dried with nitrogen, treated with ultraviolet ozone for 15 minutes, and cooled for later use.

[0047] (2) Add 750 μL of deionized water to 250 μL of a 15% SnO2 nanoparticle dispersion, filter through a 0.22 μm PVDF filter, take 40 μL and drop it onto the ITO conductive substrate pretreated in step (1), spin coat at 3000 rpm for 30 seconds, then anneal at 150°C for 30 minutes, and finally irradiate with ultraviolet ozone for 15 minutes to form an electron transport layer on the ITO conductive substrate.

[0048] (3) Preparation of perovskite light absorbing layer by one step: 248.16 mg of CH3NH3I, 19.73 mg of CsI, 6.58 mg of RbI, 682.73 mg of PbI2, 8.53 mg of PbBr2, 12.74 mg of PbCl2 and 35 mg of CH(NH2)2Cl were dissolved in 1 mL of a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO was 4:1). After oscillation for 10 min, a perovskite precursor solution with a concentration of 1.55 mol / L was obtained. After filtering through 0.22 μm PTFE, 40 μL was added dropwise to the electron transport layer in step (2). The solution was spin-coated at 4000 rpm for 30 s. 80 μL of chlorobenzene was added as an anti-solvent 15 to 16 s before the end of spin coating. The solution was then annealed at 130°C for 30 min to form a perovskite light absorbing layer on the electron transport layer.

[0049] (4) 72.3 mg of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) and 0.15 mg of calixarene supramolecular C8A were dissolved in 1 mL of chlorobenzene to obtain a mixed solution, 29 μL of 4-tert-butylpyridine (tBP) and 18 μL of lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) (the mass concentration of lithium bis(trifluoromethanesulfonyl)imide is 520 mg / mL, and the solvent is anhydrous acetonitrile) were added to the mixed solution, and 30 μL was added dropwise onto the perovskite light absorbing layer in step (4), and spin coated at a rotation speed of 3000 rpm for 30 s to form a hole transport layer on the perovskite light absorbing layer.

[0050] (5) In high vacuum (10 -4 Under the condition of 400 Å / min (200 Å / s), an Ag / Au electrode with a thickness of 80 nm is deposited on the hole transport layer in step (4) by thermal evaporation to obtain a normal perovskite solar cell in which the hole transport layer is doped with calixarene supramolecules (C8A).

[0051] Example 2

[0052] A method for preparing a perovskite solar cell. In this embodiment, a two-step method is used to prepare a perovskite light-absorbing layer. The specific preparation method includes the following steps:

[0053] (1) The FTO conductive substrate was cleaned with detergent, deionized water, acetone, and anhydrous ethanol in sequence, then dried with nitrogen, treated with ultraviolet ozone for 15 minutes, and cooled for later use.

[0054] (2) Add 750 μL of deionized water to 250 μL of a 15% SnO2 nanoparticle dispersion, filter through a 0.22 μm PVDF, take 40 μL and drop it onto the ITO conductive substrate pretreated in step (1), spin coat at 3000 rpm for 30 seconds, then anneal at 150°C for 30 minutes, and then irradiate with ultraviolet ozone for 15 minutes to form an electron transport layer on the ITO conductive substrate.

[0055] (3) Preparation of perovskite light-absorbing layer by two-step method: 0.06 mol of RbCl and 1.5 mol of PbI2 were dissolved in 1 mL of a mixture of DMF and DMSO (the volume ratio of DMF to DMSO was 9:1). After filtering through 0.22 μm PTFE, 40 μL was added dropwise to the electron transport layer in step (2). The mixture was spin-coated at 1500 rpm for 30 s. The mixture was annealed at 70 °C for 1 min in a N2 glove box to obtain a PbI2 thin film on the electron transport layer. Then, CH(NH2)2I was added at 90 mg / ml in isopropanol, and CH3NH3Cl was added at 13 mg / ml. After the solid was completely dissolved, it was filtered through 0.22 μm PTFE, and 40 μL was added dropwise to the above-mentioned cooled PbI2 film. It was spin-coated at 1800 rpm for 30 seconds, and then the film was annealed at 150°C for 15 minutes in an ambient air condition with a relative humidity of about 40%, thereby forming a perovskite light absorbing layer on the electron transport layer.

[0056] (4) 75 mg of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) and 5 mg of calixarene supramolecular C8A were dissolved in 1 mL of chlorobenzene to obtain a mixed solution, 25 μL of 4-tert-butylpyridine (tBP) and 25 μL of lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) (the mass concentration of lithium bis(trifluoromethanesulfonyl)imide is 630 mg / mL, and the solvent is anhydrous acetonitrile) were added to the mixed solution, and 30 μL was added dropwise onto the perovskite light absorbing layer in step (4), and the mixture was spin-coated at a speed of 3000 rpm for 30 s to form a hole transport layer on the perovskite light absorbing layer.

[0057] (5) In high vacuum (10 -4 Under the condition of 400 Å / min (200 Å / s), an Ag / Au electrode with a thickness of 80 nm is deposited on the hole transport layer in step (4) by thermal evaporation to obtain a normal perovskite solar cell in which the hole transport layer is doped with calixarene supramolecules (C8A).

[0058] Example 3

[0059] A normal perovskite solar cell doped with calixarene supramolecule (C6A) in the hole transport layer. The specific preparation method refers to Example 1, that is, replacing "calixarene supramolecule C8A" in Example 1 with "calixarene supramolecule C6A", and keeping the other conditions unchanged.

[0060] Example 4

[0061] A normal perovskite solar cell doped with calixarene supramolecule (C4A) in the hole transport layer. The specific preparation method refers to Example 1, that is, replacing "calixarene supramolecule C8A" in Example 1 with "calixarene supramolecule C4A", and keeping the other conditions unchanged.

[0062] Comparative Example 1

[0063] A perovskite solar cell. The specific preparation method refers to Example 1, that is, not adding "calixarene supramolecule C8A" in Example 1, and keeping the other conditions unchanged.

[0064] Performance Test

[0065] Figure 1 Theoretical calculations of the chemical interactions between calixarene supramolecules C8A, C6A, and C4A and the surfaces of Li + , Ag, and perovskite in Examples 1-4; it can be seen from Figure 1 that the atoms or groups in the calixarene supramolecule are not in a plane, and there is a cavity structure in the middle of the molecule, which can encapsulate Li + and Ag; the larger the cavity size of the calixarene supramolecule, the more Li + it can accommodate. The binding energies between the calixarene supramolecule and Li + are in the order of C4A < C6A < C8A. An 8-cup calixarene supramolecule C8A can encapsulate 4 Li + . Each calixarene supramolecule can only encapsulate one or two silver atoms, and its binding energy is relatively low. The binding energy between the calixarene supramolecule C8A and Ag is the highest, 0.646 eV; therefore, compared with other calixarene molecules of smaller sizes, C8A can more effectively prevent the diffusion of Ag; the binding energies between the calixarene supramolecules C4A, C6A, and C8A and the perovskite surface are 1.449 eV, 1.742 eV, and 2.114 eV, respectively; obviously, among all the doped calixarene supramolecules, the binding energy between C8A and the perovskite surface is the highest, indicating that C8A has the best effect in passivating surface defects and suppressing the migration of CH(NH2) 2+ and I.

[0066] Figure 2 The NMR spectra of the interaction between calixarene supramolecule C8A and Li-TFSI in Example 1 7 Li NMR and 1 H NMR; from Figure 2 a It can be seen that after the calixarene supramolecular C8A is mixed with Li-TFSI, the peak position of the Li element in the Li-TFSI molecule shifts significantly toward the low field direction; Figure 2 b It can be seen that after the calixarene supramolecular C8A is mixed with Li-TFSI, the peak position of the H element on the hydroxyl group in the C8A molecule shifts significantly toward the high field direction. The above shows that the calixarene supramolecular C8A can react with Li + The molecules react chemically through coordination bonds to form a C8A-Li host-guest complex, which effectively inhibits the Li + migration.

[0067] Figure 3 The XPS spectra of N1s and I3d of the perovskite light absorbing layer of the comparative example without coating of the calixarene supramolecule C8A and the perovskite light absorbing layer coated with the calixarene supramolecule C8A in Example 1 are shown; Figure 3 It can be seen that after the perovskite light-absorbing layer in the perovskite battery in Comparative Example 1 is modified by the calixarene supramolecular C8A, the peak positions of the N1s element and the I 3d element in the perovskite are shifted, indicating that the calixarene supramolecular C8A binds to the CH(NH2) in the perovskite through hydrogen bonds. 2+ and I - Interaction, thus fixing CH(NH2) 2+ and I - , stabilize the perovskite light-absorbing layer.

[0068] Figure 4 The TOF-SIMS spectra of the battery without calixarene supramolecular C8A doped in Comparative Example 1 and the battery doped with calixarene supramolecular C8A in Example 1 (aged for 10 days under the conditions of one sun irradiation and heating at 85°C); Figure 4 It can be seen that after aging, the battery without calixarene supramolecular C8A doped in Comparative Example 1, CH(NH2) 2+ ,I - , Li + and Ag undergo serious migration and diffusion, while the CH(NH2) 2+ There is no migration and diffusion of Ag. - and Li + Although migration occurred in the device, its migration degree was weak. The above results show that the calixarene supramolecular C8A can 2+ ,I - , Li + It forms a host-guest complex with Ag, effectively preventing or inhibiting CH(NH2) 2+ 、I-、Li +and the migration and diffusion of Ag, effectively stabilizing the perovskite light-absorbing layer, HTL, and metal electrode layer.

[0069] Figure 5 The cross-sectional SEM images of the battery without calixarene supramolecular C8A doped in Comparative Example 1 and the battery with calixarene supramolecular C8A doped in Example 1; Figure 5 It can be seen that in the battery without calixarene supramolecular C8A doped in Comparative Example 1, after aging, the functional layers such as the perovskite light absorption layer, HTL and metal electrode layer collapsed and degraded seriously, while the battery doped with calixarene supramolecular C8A in Example 1 remained intact, indicating that the use of calixarene supramolecular C8A can effectively inhibit CH(NH2) through host-guest complexation. 2+ 、I-、Li + The cross-migration and diffusion of Ag between various functional layers improve the stability of the perovskite light-absorbing layer, HTL, metal electrode layer and the complete device.

[0070] Figure 6 is a high-resolution mass spectrum of the interaction between the calixarene supramolecular C8A and Li-TFSI in Example 1; Figure 6 It can be seen that the molecular mass of the calixarene supramolecular C8A is 1297.85. After reacting with Li-TFSI, the molecular mass is 1303.85, which is exactly the molecular mass of the calixarene supramolecular C8A after losing a proton and adding Li + The sum of the molecular masses indicates that a proton was removed during the reaction of the calixarene supramolecular C8A with Li-TFSI.

[0071] Figure 7 Schematic diagram of the doping mechanism of the calixarene supramolecular C8A on HTL in Example 1. Figure 7 It can be seen that the calixarene supramolecular C8A has two doping mechanisms for HTL. The first is the direct P-type doping of HTL by the calixarene supramolecular C8A. + , free H + The neutral Spiro-OMeTAD is oxidized; the second is indirect doping, where the calixarene supramolecular C8A is doped with Li + Formation of C8A-Li host-guest complex promotes the dissociation of Li-TFSI into Li + and TFSI-, thereby promoting the oxidation of neutral Spiro-OMeTAD by TFSI-.

[0072] Figure 8ESR spectra of the pure Spiro hole transport layer (Spiro), the hole transport layer doped with calixarene supramolecular C8A (Spiro-C8A), the hole transport layer doped with Li-TFSI and tBP (Spiro@Li), and the hole transport layer doped with Li-TFSI, tBP and calixarene supramolecular C8A (Spiro@Li-C8A) in Example 1; Figure 8 It can be seen that under a magnetic field of ~3360G, the ESR signal of the hole transport layer (HTL) is enhanced after being doped with calixarene supramolecular C8A, but the signal intensity is weaker than that of the hole transport layer doped with Li-TFSI (Spiro@Li), while the hole transport layer co-doped with calixarene supramolecular C8A, Li-TFSI and tBP (Spiro@Li-C8A) has the strongest ESR signal intensity, indicating that after co-doping with calixarene supramolecular C8A, due to the dual doping effect of calixarene supramolecular C8A, there are more Spiro-OMeTAD in the HTL. ·+ The free radical cation indicates that the calixarene supramolecular C8A promotes the oxidation of neutral Spiro-OMeTAD.

[0073] Fig. 9 The conductivity of the hole transport layer of pure Spiro (Spiro), the hole transport layer doped with calixarene supramolecular C8A (Spiro-C8A), the hole transport layer doped with Li-TFSI and tBP (Spiro@Li), and the hole transport layer doped with Li-TFSI, tBP and calixarene supramolecular C8A (Spiro@Li-C8A) in Example 1; Fig. 9 It can be seen that after co-doping with the calixarene supramolecular C8A, the hole transport layer (Spiro@Li-C8A) shows the best conductivity, indicating that the dual doping effect of the calixarene supramolecular C8A on Spiro-OMeTAD improves the conductivity of the hole transport layer (Spiro@Li-C8A).

[0074] Fig.10 The XPS Pb 4f spectra of the silver electrode layer of the comparative example not coated with the calixarene supramolecular C8A and the perovskite light absorbing layer coated with the calixarene supramolecular C8A in Example 1 are shown; Fig.10 It can be seen that after the perovskite light-absorbing layer in the perovskite battery in Comparative Example 1 is modified by the calixarene supramolecular C8A, the peak position of the Pb 4f element in the perovskite light-absorbing layer is significantly shifted, indicating that the calixarene supramolecular C8A can effectively passivate the uncoordinated Pb on the surface of the perovskite. + / Halogen vacancy defect.

[0075] Fig.11The dark state IV curves of the ITO / PTAA / Spiro-OMeTAD@Li-TFSI / Ag perovskite structure device not doped with the calixarene supramolecule C8A in Comparative Example 1 and the ITO / PTAA / Spiro-OMeTAD@Li-TFSI-C8A / Ag doped with the calixarene supramolecule C8A in Example 1; Fig.11 It can be seen that after the perovskite light-absorbing layer of the perovskite battery in Comparative Example 1 is modified by the calixarene supramolecule C8A, the defect density is significantly reduced, indicating that the calixarene supramolecule C8A effectively passivates the perovskite defects.

[0076] Fig.12 is the current density-voltage curve of the perovskite solar cell prepared in Comparative Example 1 and Example 1; Fig.12 The photovoltaic parameters of the perovskite solar cells prepared in Comparative Example 1 and the Examples were obtained, and the results are shown in Table 1.

[0077] Table 1 Photovoltaic parameters of perovskite solar cells prepared in Comparative Example 1 and Example 1

[0078] <![CDATA[Short-circuit current density (mA / cm 2 )]]> Open circuit voltage(V) Fill factor (%) PCE(%) Comparative Example 1 23.94 1.152 79.91 22.05 Example 1 24.91 1.195 85.00 25.30

[0079] from Fig.12 As can be seen from Table 1, compared with the solar cell formed by the hole transport layer of undoped calixarene supramolecular C8A in Comparative Example 1, the short-circuit current density, open-circuit voltage and fill factor of the perovskite solar cell formed by the hole transport layer doped with calixarene supramolecular C8A in Example 1 are significantly improved, and the power conversion efficiency is increased from 22.05% in Comparative Example 1 to 25.30%. Compared with the solar cell in Comparative Example 1, the PCE is greatly improved.

[0080] Fig.13 is the current density-voltage curve of the perovskite solar cell prepared in Comparative Example 1 and Example 2; Fig.13 The photovoltaic parameters of the perovskite solar cells prepared in Comparative Example 1 and Example 2 were obtained, and the results are shown in Table 2.

[0081] Table 2 Photovoltaic parameters of perovskite solar cells prepared in Comparative Example 1 and Example 2

[0082] <![CDATA[Short-circuit current density (mA / cm 2 )]]> Open circuit voltage(V) Fill factor (%) PCE(%) Comparative Example 1 25.45 1.174 81.97 24.48 Example 2 26.19 1.187 81.29 25.27

[0083] from Fig.13As can be seen from Table 2, compared with the solar cell formed by the hole transport layer of undoped calixarene supramolecule C8A in Comparative Example 1, the short-circuit current density and open-circuit voltage of the perovskite solar cell formed by the hole transport layer doped with calixarene supramolecule C8A in Example 2 are significantly improved, and the power conversion efficiency is increased from 24.48% in Comparative Example 1 to 25.27%. Compared with the solar cell in Comparative Example 1, the PCE is greatly improved, indicating that the doping of calixarene supramolecule C8A is suitable for cells of different perovskite types.

[0084] Fig.14 The MPP stability test results of the unencapsulated perovskite solar cells in Comparative Example 1 and Example 1 are shown. Fig.14 It can be seen that after the unpackaged device was continuously operated for 1015 hours under 1 sun irradiation in the N2 glove box, the battery in Example 1 retained ~81.4% of the initial PCE through the tracking of the maximum power point, while the efficiency of the device in Comparative Example 1 has tended to 0, indicating that after the co-doping of the calixarene supramolecular C8A in the hole transport layer, due to the simultaneous fixation of CH(NH 2 ) 2+ ,I - , Li + and Ag, which greatly improves the operating stability of solar cells.

[0085] Fig.15 The thermal stability test results of the unpackaged perovskite solar cells in Comparative Example 1 and Example 1 are shown in FIG. Fig.15 It can be seen that the unencapsulated perovskite solar cell in Example 1 maintains ~91.00% of the initial efficiency after heat aging at 65°C for 1750h. Compared with the solar cell in Comparative Example 1, the thermal stability of the cell in Example 1 is greatly improved.

[0086] Fig.16 The humidity stability test results of the unencapsulated perovskite solar cells in Comparative Example 1 and Example 1 are shown; Fig.16 It can be seen that the unpackaged perovskite solar cell in the embodiment maintains 90.00% of the initial efficiency after aging for 2800 hours under a relative humidity condition of 25%-35%, which has a significant improvement in moisture resistance compared to the solar cell in Comparative Example 1.

[0087] Fig.17 The current density v voltage curve of the perovskite solar cell prepared by the one-step method in Comparative Example 1 and Example 3; Fig.17 The photovoltaic parameters of the perovskite solar cells prepared in Comparative Example 1 and Example 3 are obtained, and the results are shown in Table 3. Fig.17As shown in Table 3, compared with Comparative Example 1, the open circuit voltage of the perovskite solar cell prepared in Example 3 is improved, and the power conversion efficiency is increased from 22.05% in Comparative Example 1 to 24.80%.

[0088] Table 3 Photovoltaic parameters of perovskite solar cells prepared by one-step method in Comparative Example 1 and Example 3

[0089] <![CDATA[Short-circuit current density (mA / cm 2 )]]> Open circuit voltage(V) Fill factor (%) PCE(%) Example 3 24.83 1.186 84.21 24.80

[0090] Fig.18 The current density-voltage curves of the perovskite solar cells prepared by the one-step method in Comparative Example 1 and Example 4; Fig.18 The photovoltaic parameters of the perovskite solar cells prepared in Comparative Example 1 and Example 4 are obtained, and the results are shown in Table 4. Fig.18 As shown in Table 4, compared with Comparative Example 1, the open circuit voltage of the perovskite solar cell prepared in Example 4 is improved, and the power conversion efficiency is increased from 22.05% in Comparative Example 1 to 24.00%.

[0091] Table 4 Photovoltaic parameters of perovskite solar cells prepared by one-step method in Comparative Example 1 and Example 4

[0092] <![CDATA[Short-circuit current density (mA / cm 2 )]]> Open circuit voltage(V) Fill factor (%) PCE(%) Example 4 24.64 1.172 83.14 24.00

[0093] Similarly, after analysis, it can be found that in the hole transport layer, the action mechanism between the calixarene supramolecule (C6A) and the calixarene supramolecule (C4A) and 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro OMeTAD), p-tert-butylpyridine (tBP) and lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) is the same as that of the calixarene supramolecule (C8A) in Example 1; therefore, the three calixarene supramolecules C4A, C6A and C8A can be doped in the hole transport layer of the perovskite to modify its performance.

[0094] The calixarene supramolecule has relevant properties and application effects similar to those of the products prepared in Examples 1 to 4.

[0095] In addition, in the process of preparing solar cells with the prepared calixarene supramolecules, the rotation speed during spin coating can be between 2500 and 6500 rpm and the spin coating time can be between 20 and 60 s; the annealing process is specifically annealing at 80 to 150° C. for 5 to 30 min; the anti-solvent used is one or more of chlorobenzene, dichloromethane, dichlorobenzene, toluene, ethyl acetate, chloroform or ether; the concentration of the calixarene supramolecule solution is 0.01 to 5.0 mg / mL; the electron transport layer material in the electron transport layer solution is any one or more of SnO2, TiO2, ZnO, BaSnO3 or CeO2. Since the interaction between the calixarene supramolecules doped in the hole transport layer and 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro OMeTAD), LiTFSI and tBP is not affected, the changes in the above parameters do not affect the performance of the prepared solar cell.

[0096] In summary, the present invention simultaneously fixes CH(NH 2 ) 2+ ,I - , Li + and Ag, passivating interface defects, improving the conductivity of the hole transport layer with Spiro-OMeTAD as the hole material, and stabilizing the perovskite light absorption layer, hole transport layer and metal electrode layer, thereby simultaneously improving the power conversion efficiency and stability of the device, and realizing the controllable preparation of efficient and stable perovskite solar cells. The process of doping HTL with calixarene supramolecular in the present invention is simple and has good repeatability, which is of great significance in promoting the industrialization process of perovskite solar cells.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. Application of a calixarene supramolecule in the preparation of a perovskite solar cell, characterized in that: Preparation of hole transport layers for perovskite solar cells using calixarene supramolecules.

2. The use of the calixarene supramolecule according to claim 1 in the preparation of perovskite solar cells, characterized in that: The structural formulas of the calixarene supramolecule are shown in Formula I, Formula II and Formula III, wherein Formula I is C4A, Formula II is C6A, and Formula III is C8A; 3. The use of the calixarene supramolecule according to claim 1 in the preparation of perovskite solar cells, characterized in that: The preparation method of the hole transport layer is as follows: 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene and calixarene supramolecules are added to chlorobenzene and mixed evenly to obtain a mixed solution; the mixed solution, 4-tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide solution are mixed to obtain a hole transport layer solution; and the hole transport layer solution is spin-coated on a perovskite light absorption layer to form a hole transport layer.

4. The use of the calixarene supramolecule according to claim 3 in the preparation of perovskite solar cells, characterized in that: The amount of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene added in chlorobenzene is 70-75 mg / mL, and the amount of calixarene supramolecule added is 0.01-5.00 mg / mL; the volume ratio of the mixed solution, 4-tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide solution is 1:(25-35):(15-25).

5. The use of the calixarene supramolecule according to any one of claims 1 to 4 in the preparation of perovskite solar cells, characterized in that: The specific preparation steps of the perovskite solar cell are as follows: (1) spin coating an electron transport layer solution on a pretreated conductive substrate, and after annealing, performing ultraviolet ozone irradiation or plasma treatment to form an electron transport layer on the conductive substrate; (2) spin coating the perovskite precursor solution on the electron transport layer in step (1), adding an anti-solvent, and annealing to form a perovskite light absorbing layer on the electron transport layer; (3) spin coating the hole transport layer solution on the perovskite light absorbing layer in step (2) to form a hole transport layer on the perovskite light absorbing layer; (4) Prepare a metal back electrode on the hole transport layer described in step (3).

6. The use of the calixarene supramolecule according to claim 5 in preparing a perovskite solar cell, characterized in that: The material of the conductive substrate layer in step (1) is any one of ITO and FTO; the pretreatment is: the material of the conductive substrate layer is ultrasonically cleaned with detergent, deionized water, acetone, and anhydrous ethanol in sequence, then dried with nitrogen, and treated with ultraviolet ozone for 10 to 50 minutes.

7. The method for preparing a perovskite solar cell according to claim 1, characterized in that: In step (1), the electron transport layer is one or more of SnO2, TiO2, ZnO, BaSnO3 or CeO2, or a mixture of them in any proportion; the ultraviolet ozone irradiation treatment or plasma treatment time is 20 to 100 minutes.

8. The method for preparing a perovskite solar cell according to claim 1, characterized in that: In step (2), the perovskite light absorbing layer is ABX3, where A is CH3NH3 + or CH(NH2)2 + , B is Cs + , Rb + , Pb 2+ Sn 2+ Or Ge 2+ One of the following, X is Cl - Br - or one of I-; the anti-solvent is any one of chlorobenzene, dichloromethane, dichlorobenzene, toluene, ethyl acetate, chloroform or ether or a mixture of any two or more thereof in any proportion.

9. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The metal back electrode in step (4) is any one of Au, Ag or low-temperature carbon electrode.

10. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The spin coating conditions in all steps are a rotation speed of 2500-6500 rpm and a time of 20-60 s; the annealing temperature in all steps is 80-150° C. and a time of 5-30 min.

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