A perovskite solar cell and a method for preparing the same

Abstract

The present invention provides a perovskite solar cell and a preparation method thereof, wherein the perovskite solar cell comprises a conductive substrate, a hole transport layer, a perovskite light absorption layer, an interface passivation layer, an electron transport layer and an electrode arranged in sequence; the interface passivator of the interface passivation layer comprises at least one compound having a structure shown in general formula I. The perovskite solar cell has a high conversion efficiency and a long service life by arranging a specific interface passivation layer between the perovskite light absorption layer and the electron transport layer, and is particularly suitable for wide bandgap perovskite solar cells, solving the problem of large opening voltage loss in wide bandgap perovskite solar cells due to non-radiative recombination at the interface between the perovskite and the electron transport layer in the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and in particular relates to a perovskite solar cell and a preparation method thereof. Background Art

[0002] Traditional non-renewable energy is drying up, and solar energy, as an inexhaustible clean energy source, has become the focus of human attention. Solar energy has a wide coverage and is pollution-free, making it the most promising new energy source. The working principle of solar cells is to convert sunlight into electrical energy. Among them, organic-inorganic hybrid perovskite solar cells are currently a popular new battery technology. In just a few years, the energy conversion efficiency has been greatly improved. In addition, this type of material has the advantages of high light absorption rate, long carrier lifetime, adjustable band gap, low cost, simple preparation process, etc., and is widely used.

[0003] The band gap of perovskite materials can be adjusted in the range of 1.2~3.0 eV, making it very advantageous as a wide bandgap top cell in stacking technology. Among them, the theoretical efficiency of perovskite crystalline silicon stacked cells is as high as 45.1%, and the laboratory has currently achieved an efficiency of 33.9%. However, wide bandgap perovskite cells face serious open circuit voltage loss problems. The open circuit voltage loss of perovskite cells with a band gap of 1.5 eV is usually 0.3 V, while the open circuit voltage loss of perovskite cells with a band gap of 1.68~1.75 eV is usually greater than 0.5 V. Studies have shown that once a wide bandgap perovskite cell directly contacts the charge transport layer, its photoluminescence quantum yield (PLQY) will be significantly reduced, which indicates that some recombination will occur at the interface between the wide bandgap perovskite and the transport layer. These non-radiative recombination is mainly caused by band mismatch and the migration of halogen ions to the transport layer. These non-radiative recombination is the main reason for the open voltage loss of wide bandgap perovskite cells.

[0004] Therefore, developing a wide-bandgap perovskite cell with high conversion efficiency, good stability, and avoiding open-circuit voltage loss due to non-radiative recombination is an urgent problem to be solved in this field. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a perovskite solar cell and a preparation method thereof. The perovskite solar cell has a high conversion efficiency, a long service life, and a small efficiency decay after continuous illumination by setting a specific interface passivation layer between the perovskite light absorption layer and the electron transport layer, and is particularly suitable for wide bandgap perovskite solar cells, solving the problem of large opening voltage loss in wide bandgap perovskite solar cells due to non-radiative recombination at the interface between the perovskite and the electron transport layer in the prior art.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a conductive substrate, a hole transport layer, a perovskite light absorption layer, an interface passivation layer, an electron transport layer and an electrode arranged in sequence; the interface passivator of the interface passivation layer comprises at least one compound having a structure shown in general formula I;

[0008] General formula I.

[0009] Among them, R1, R 5+i are each independently selected from H or halogen, and R1, R 5+i At least one of them is selected from halogen; R2, R3, R4, and R5 are each independently selected from H, substituted or unsubstituted C1-C20 straight or branched alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 condensed aryl, substituted or unsubstituted C5-C30 heteroaryl, substituted or unsubstituted C5-C30 condensed heteroaryl; i is selected from an integer of 0-7, and when i>1, R 5+i the same or different; the substituted substituent includes halogen; the halogen includes F, Cl, Br or I.

[0010] In the present invention, the interface passivator contains an electron-rich group halogen, has a high surface electrostatic potential, and the halogen atoms can react with Pb 2+ A strong coordination bond is formed, thereby passivating the dangling bonds on the surface of the perovskite grains. At the same time, during the operation of the device, the halogen ions in the perovskite migrate from the perovskite layer to the electron transport layer. The electrostatic potential of the interface passivator will repel the negatively charged ions, thereby preventing the halogen ions from migrating from the perovskite layer to the electron transport layer, greatly improving the migration of halogen ions during the operation of the battery; reducing the non-radiative recombination of the device, so that the photogenerated carrier excitons can be effectively separated during the operation of the device, the charge transfer efficiency is improved, and the device efficiency, stability and service life are greatly improved.

[0011] In the present invention, the C1~C20 refers to a molecular structure containing 1~20 carbon atoms, for example, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, etc.; the C3~C20 refers to a molecular structure containing 3~20 carbon atoms, for example, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, etc.; the C6~C30 refers to a molecular structure containing 6~30 carbon atoms, for example, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, etc.; the C5~C30 refers to a molecular structure containing 5~30 carbon atoms, for example, 5, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, etc.

[0012] In the present invention, the i is selected from an integer of 0 to 7, for example, 0, 1, 2, 3, 4, 5, 6, 7, etc.

[0013] In the present invention, R 5+i It means that when i is 1, the group in the brackets is R6, and when i is 2, the groups in the brackets are R6, R7, and so on.

[0014] In some embodiments of the present invention, in order to further improve the conversion efficiency and service life of the perovskite solar cell, it is further preferred that i is selected from an integer of 4 to 6.

[0015] Preferably, R2, R3, R4 and R5 are each independently selected from H.

[0016] The R1, R 5+i Each is independently selected from H or I.

[0017] In some embodiments of the present invention, in order to further improve the conversion efficiency and service life of the perovskite solar cell, R1, R 5+i Each is independently selected from I.

[0018] Preferably, the interface passivator is selected from at least one of the following structural compounds;

[0019] , , , , .

[0020] In the present invention, in order to further improve the conversion efficiency and service life of the perovskite solar cell, the interface passivator is further preferably , or At least one of .

[0021] In the present invention, the interface passivator can be prepared by conventional methods in the prior art. For example, the method includes: mixing a halogen, a condensed ring compound and a solvent, ball milling and washing, and then drying and cracking the obtained mixture to obtain the interface passivator.

[0022] In the present invention, the solvent includes but is not limited to ethanol; based on the mass of the halogen and the condensed ring compound being 0.64 g, the volume of the solvent is 15 to 30 mL, for example, 15 mL, 16 mL, 18 mL, 20 mL, 22 mL, 24 mL, 26 mL, 28 mL, 30 mL, etc.

[0023] In the present invention, the rotation speed of the ball mill is 1-500 rpm, and the time is 4-8 h; the drying temperature is 40-60°C, and the time is 12-48 h; the cracking is carried out in the presence of a protective atmosphere (including but not limited to argon); the cracking temperature is 200-400°C, and the time is 5-15 h.

[0024] Preferably, the mass concentration of the interfacial passivator is 0.1~5 mg / mL, for example, it can be 0.1 mg / mL, 0.2 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, 0.8 mg / mL, 1 mg / mL, 1.2 mg / mL, 1.4 mg / mL, 1.6 mg / mL, 1.8 mg / mL, 2 mg / mL, 2.2 mg / mL, 2.4 mg / mL, 2.6 mg / mL, 2.8 mg / mL, 3 mg / mL, 3.2 mg / mL, 3.4 mg / mL, 3.6 mg / mL, 3.8 mg / mL, 4 mg / mL, 4.2 mg / mL, 4.4 mg / mL, 4.6 mg / mL, 4.8 mg / mL, 5 mg / mL and the like.

[0025] In the present invention, the mass concentration of the interface passivator is related to the thickness of the interface passivation layer. The higher the concentration, the thicker the interface passivation layer. If the mass concentration is too low, the improvement effect is poor, the conversion efficiency of the device is low, and the stability is poor. If the mass concentration is too high, the extraction of electrons generated by the perovskite by the electron transport layer is reduced, which leads to a decrease in the open circuit voltage, and also reduces the efficiency and stability of the device.

[0026] In the present invention, the general structural formula of the material of the perovskite light-absorbing layer is ABX3.

[0027] Wherein, A is selected from CH3NH3 + 、CH2(NH3)2 + or Cs + Any one or a combination of at least two of the following: B is selected from Pb2+ and / or Sn 2+ ; X is selected from I - Br - or Cl - Any one or a combination of at least two of the following:

[0028] The thickness of the perovskite light absorbing layer is 300-900 nm, for example, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, etc.

[0029] The material of the perovskite light absorbing layer includes a wide bandgap perovskite material, and the bandgap of the wide bandgap perovskite material is 1.65-1.75 eV.

[0030] Preferably, the material of the electron transport layer includes C 60 SnO x Or any one of 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline or a combination of at least two thereof.

[0031] The thickness of the electron transport layer is 5 to 40 nm, for example, 5 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, 30 nm, 32 nm, 34 nm, 36 nm, 38 nm, 40 nm, etc.

[0032] In the present invention, the electron transport layer comprises C 60 Electron transport layer and SnO x Electron transport layer; or, comprising C 60 electron transport layer and 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline electron transport layer; the C 60 The thickness of the electron transport layer is 20~30 nm.

[0033] The material of the hole transport layer includes any one of nickel oxide, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2-PACz) or [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz) or a combination of at least two thereof.

[0034] The thickness of the hole transport layer is 5 to 30 nm, for example, 5 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, 30 nm, etc.

[0035] In some embodiments of the present invention, it is preferred that the material of the hole transport layer comprises a combination of nickel oxide and [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphoric acid.

[0036] The mass concentration ratio of the nickel oxide to [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid is (6.5-8.5):0.03, for example, it can be 6.5:0.03, 6.6:0.03, 6.8:0.03, 7:0.03, 7.2:0.03, 7.4:0.03, 7.6:0.03, 7.8:0.03, 8:0.03, 8.2:0.03, 8.4:0.03, etc.

[0037] Preferably, the conductive substrate includes any one of an indium tin oxide conductive glass substrate (ITO conductive glass substrate), a fluorine-doped SnO2 conductive glass substrate (FTO conductive glass substrate) or an aluminum-doped ZnO conductive glass substrate (AZO conductive glass substrate).

[0038] The thickness of the conductive substrate is 20-200 nm, for example, 20 nm, 40 nm, 60 nm, 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm, 200 nm, etc.

[0039] Preferably, the electrodes comprise metal electrodes.

[0040] The thickness of the electrode is 80-120 nm, for example, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, etc.

[0041] In a second aspect, the present invention provides a method for preparing a perovskite solar cell according to the first aspect, the preparation method comprising: stacking a conductive substrate, a hole transport layer, a perovskite light absorption layer, an interface passivation layer, an electron transport layer and an electrode in sequence to obtain the perovskite solar cell.

[0042] In the present invention, the conductive substrate further includes a washing step before use; the washing includes: ultrasonically cleaning with glass cleaning fluid, deionized water, ethanol and isopropanol in sequence, drying at 150-250° C., drying with a nitrogen stream, and then washing with ultraviolet ozone for 10-20 min.

[0043] In the present invention, the method for setting the hole transport layer includes a solution method and / or a magnetron sputtering method; the solution method includes coating the hole transport layer material on the surface of the conductive substrate, annealing, and obtaining the hole transport layer; the coating speed is 2000-4000 rpm, for example, it can be 2000 rpm, 2200 rpm, 2500 rpm, 2800 rpm, 3000 rpm, 3200 rpm, 3500 rpm, 3800 rpm, 4000 rpm, etc.; the time is 20-40 s, for example, it can be 20 s, 22 s, 25 s, 28 s, 30 s, 32 s, 35 s, 38 s, 40 s, etc.; the annealing temperature is 80-140°C, for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 110°C, 120°C, 130°C, 140°C, etc.; the time is 5-15 min, for example, it can be 5 min, 6 min, 7min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, etc.

[0044] In the present invention, the preparation method of the perovskite light-absorbing layer comprises: coating a perovskite precursor solution on the surface of the obtained hole transport layer, adding an anti-solvent during the coating process, and annealing to obtain the perovskite light-absorbing layer; the coating rotation speed is 3000-5000 rpm, for example, it can be 3000 rpm, 3200 rpm, 3500 rpm, 3800 rpm, 4000 rpm, 4200rpm, 4500 rpm, 4800 rpm, 5000 rpm, etc.; the time is 25-40 s, for example, it can be 25 s, 28 s, 30 s, 32 s, 35 s, 38 s, 40 s, etc.; the annealing temperature is 80-140°C, for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 110°C, 120°C, 130°C, 140°C, etc.; the time is 5-15 min, for example, it can be 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, etc.

[0045] In the present invention, the time for adding the anti-solvent accounts for 0.6 to 0.8 of the total coating time.

[0046] In the present invention, the preparation method of the interface passivation layer comprises: coating an interface passivator on the surface of the obtained perovskite light-absorbing layer, annealing, and obtaining the interface passivation layer; the coating rotation speed is 1000-3000 rpm, for example, it can be 1000 rpm, 1200 rpm, 1500 rpm, 1800 rpm, 2000 rpm, 2200 rpm, 2500 rpm, 2800 rpm, 3000 rpm, etc.; the time is 10-30 s, for example, it can be 10 s, 12 s, 15 s, 18 s, 20 s, 22 s, 25 s, 28 s, 30 s, etc.; the annealing temperature is 80-140°C, for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 110°C, 120°C, 130°C, 140°C, etc.; the time is 5-15 min, for example, it can be 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, etc.

[0047] In the present invention, the preparation method of the electron transport layer comprises: depositing an electron transport layer material on the surface of the obtained interface passivation layer to obtain the electron transport layer; the deposition method comprises evaporation; the evaporation rate is 0.05~0.2nm / s, for example, it can be 0.05 nm / s, 0.06 nm / s, 0.08 nm / s, 0.1 nm / s, 0.12 nm / s, 0.14 nm / s, 0.16 nm / s, 0.18 nm / s, 0.2 nm / s, etc.

[0048] In the present invention, the preparation method of the electrode comprises: depositing metal on the surface of the obtained electron transport layer to obtain the electrode; the deposition method comprises evaporation; the evaporation rate is 0.1~0.3 nm / s, for example, it can be 0.1 nm / s, 0.12 nm / s, 0.14 nm / s, 0.16 nm / s, 0.18 nm / s, 0.2 nm / s, 0.22 nm / s, 0.24 nm / s, 0.26nm / s, 0.28 nm / s, 0.3 nm / s, etc.

[0049] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The perovskite solar cell provided by the present invention can passivate the Pb on the surface of the perovskite by providing a specific interface passivation layer between the perovskite light absorption layer and the electron transport layer. 2+ Defects can be eliminated, and the migration of halogen ions can be suppressed by electrostatic potential, thereby improving the efficiency and stability of perovskite solar cells. It is particularly suitable for wide-bandgap perovskite solar cells, and solves the problem of large opening voltage loss in wide-bandgap perovskite solar cells in the prior art due to non-radiative recombination at the interface between perovskite and electron transport layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic diagram of the structure of a perovskite solar cell provided by the present invention;

[0053] Among them, 1-conductive substrate; 2-hole transport layer; 3-perovskite light absorption layer; 4-interface passivation layer; 5-electron transport layer; 6-electrode. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0055] Unless otherwise specified, the materials used in the present invention are as follows:

[0056] Interface passivator (M1-M5)

[0057] M1: ;

[0058] M2: ;

[0059] M3: ;

[0060] M4: ;

[0061] M5: .

[0062] Taking M1 as an example: the preparation method includes: 1 mmol iodine and 0.66 mmol pyrido[2,3-b][1,8]naphthyridine reactant (available, CAS No. 261-15-4) are uniformly dispersed in 20 mL ethanol, and then ball milled at 500 rpm for 6 h, the centrifuge and ethanol are washed, and the obtained mixture is dried at 50 ° C and vacuum for 24 h, and then heated at 300 ° C under argon for 10 h;

[0063] Among them, the preparation methods of M2-M5 differ from those of M1 in that: 1) the molar ratio of elemental iodine and another reactant (condensed ring compound) is adjusted according to the ratio of iodine atoms and condensed ring compounds in the product; 2) the number of condensed rings in the other reactant (condensed ring compound) is different.

[0064] Example 1

[0065] This embodiment provides a perovskite solar cell, and its structural schematic diagram is as follows Figure 1 As shown; comprising a conductive substrate 1, a hole transport layer 2, a perovskite light absorption layer 3, an interface passivation layer 4, an electron transport layer 5 and an electrode 6 stacked in sequence; the preparation method of the perovskite solar cell comprises the following steps:

[0066] (1) Cleaning the ITO conductive glass substrate: The ITO conductive glass substrate was ultrasonically cleaned with glass cleaning solution, deionized water, ethanol, and isopropanol in sequence, dried at 200 degrees, blown dry with a nitrogen stream, and then cleaned with ultraviolet ozone for 15 minutes to obtain a conductive substrate 1.

[0067] (2) Preparation of hole transport layer 2: 10 mg / mL NiOx nanoparticle aqueous solution and isopropanol were mixed in a volume ratio of 3:1, and then dropped onto the surface of the ITO conductive glass substrate obtained in step (1), and spin-coated using a coater at a speed of 3000 rpm for 30 s; then quickly transferred to a nitrogen atmosphere, 0.03 mg / mL Me-4PACz ethanol solution was spin-coated on the NiOx surface, and spin-coated using a coater at a speed of 3000 rpm for 30 s; then placed on a heating table for annealing; the annealing temperature was 100°C, and the annealing time was 10 min, to obtain the hole transport layer.

[0068] (3) Preparation of perovskite light absorbing layer 3: CsI, FAI, PbI2, and PbBr2 are prepared into FA according to the molar ratio of 2:8:4:6. 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3, the concentration of the precursor solution is 1.2 M, the solvent is DMF and DMSO solution with a volume ratio of 4:1; stirring for 2 hours to fully dissolve it, filtering to obtain a clear solution, that is, obtaining a perovskite precursor solution; taking 100 μL of the perovskite precursor solution and adding it dropwise to the surface of the hole transport layer obtained in step (3), at a rotation speed of 4000 rpm, spin coating for 32 s, adding 100 μL of chlorobenzene as an anti-solvent at the 24th second, annealing at 100°C for 10 min, to obtain the perovskite light absorbing layer.

[0069] (4) Prepare the interface passivation layer 4. Dissolve the interface passivator M2 in chlorobenzene at a concentration of 0.5 mg / mL, spin-coat it on the surface of the perovskite light-absorbing layer at a rotation speed of 2000 rpm for 20 s, and anneal at 100° C. for 10 min to obtain the interface passivation layer.

[0070] (5) Preparation of electron transport layer: 25 nm of C60 and 8 nm of 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) were deposited on the surface of the interface passivation layer obtained in step (4) by vacuum evaporation. The evaporation rate was controlled at about 0.1 nm / s.

[0071] (6) Depositing a silver electrode with a thickness of 100 nm on the electron transport layer obtained in step (5) by vacuum evaporation, with the evaporation rate controlled at about 0.2 nm / s, to obtain the perovskite solar cell.

[0072] Example 2

[0073] This embodiment provides a perovskite solar cell, which differs from Embodiment 1 only in that the concentration of the interface passivator in step (4) is 0.1 mg / mL, and other materials, amounts and preparation methods are the same as those in Embodiment 1.

[0074] Example 3

[0075] This embodiment provides a perovskite solar cell, which differs from Embodiment 1 only in that the concentration of the interface passivator in step (4) is 1 mg / mL, and other materials, amounts and preparation methods are the same as those in Embodiment 1.

[0076] Example 4

[0077] This embodiment provides a perovskite solar cell, which is different from the embodiment 1 only in that the concentration of the interface passivator in step (4) is 5 mg / mL, and the other materials, amounts and preparation methods are the same as those in the embodiment 1.

[0078] Example 5

[0079] This embodiment provides a perovskite solar cell, which differs from the embodiment 1 only in that the interface passivator in step (4) is M1 of equal concentration, and other materials, amounts and preparation methods are the same as those in the embodiment 1.

[0080] Example 6

[0081] This embodiment provides a perovskite solar cell, which differs from the embodiment 1 only in that the interface passivating agent in step (4) is M5 of equal concentration, and other materials, amounts and preparation methods are the same as those in the embodiment 1.

[0082] Example 7

[0083] This embodiment provides a perovskite solar cell, which differs from the embodiment 1 only in that the interface passivator in step (4) is M3 of equal concentration, and other materials, amounts and preparation methods are the same as those in the embodiment 1.

[0084] Example 8

[0085] This embodiment provides a perovskite solar cell, which differs from the embodiment 1 only in that the interface passivator in step (4) is M4 of equal concentration, and other materials, amounts and preparation methods are the same as those in the embodiment 1.

[0086] Comparative Example 1

[0087] This comparative example provides a perovskite solar cell, which differs from Example 1 only in that the perovskite solar cell does not have an interface passivation layer, step (4) is not performed in the preparation method, and other materials, amounts used, and preparation methods are the same as those in Example 1.

[0088] Comparative Example 2

[0089] This comparative example provides a perovskite solar cell, which differs from Example 1 only in that the interface passivator in step (4) is polyacrylonitrile (Mw~15000) of equal concentration, and other materials, amounts and preparation methods are the same as those in Example 1.

[0090] Performance Testing

[0091] The open circuit voltage (Voc), short circuit current (Jsc), fill factor (FF) and initial photoelectric conversion efficiency (PCE) of the perovskite solar cells provided in Examples 1 to 8 and Comparative Examples 1 and 2 were tested, and the conversion efficiency retention rate after attenuation of the obtained perovskite solar cells was tested after 500 hours of continuous illumination at AM1.5 (retention rate = conversion efficiency after 500 hours of continuous illumination at AM1.5 / initial conversion efficiency); the test results are shown in Table 1.

[0092] The specific test results are shown in Table 1:

[0093] Table 1

[0094]

[0095] As can be seen from Table 1, the perovskite solar cell provided by the present invention, by setting a specific interface passivation layer between the perovskite light absorption layer and the electron transport layer, makes the conversion efficiency of the perovskite solar cell greater than 20.0%. After 500 hours of continuous illumination at AM1.5, the conversion efficiency retention rate can still reach more than 95%, and the stability is good.

[0096] It can be seen from Examples 1 to 4 that within a certain range, as the concentration of the interface passivator increases, the thickness of the interface passivation layer increases, and its open circuit voltage increases significantly, ultimately leading to an increase in conversion efficiency. When the concentration is further increased, its open circuit voltage begins to decrease, which may be because the excessively thick interface passivation layer reduces the extraction of electrons generated by the perovskite by the electron transport layer.

[0097] It can be seen from Examples 1 to 8 and Comparative Example 1 that compared with the structure in which the perovskite light absorption layer and the electron transport layer are in direct contact, that is, the perovskite battery without an interface passivation layer, its open circuit voltage is as low as 1.18V, indicating that the perovskite battery provided by the present invention increases the opening voltage by at least 0.05V. The addition of interface passivators of different structures (Example 1, Examples 5-8) can all play the role of increasing the open circuit voltage, and the opening voltage can be increased by 0.08~0.11V, among which M2 has the most significant increase in the opening voltage, and the opening voltage is increased by 0.11V, which ultimately leads to a 2.92% increase in device efficiency compared to the device in Comparative Example 1. In addition, in addition to the significant increase in the opening voltage, the introduction of this layer also significantly improves the device life of the wide bandgap perovskite battery. After the optimal device works for 500 hours under continuous illumination of AM1.5, its efficiency decays to 98.4% of the initial value, while Comparative Example 1 decays to 88.1% of the initial value, and the device life is significantly reduced.

[0098] Compared with Example 1 and Comparative Example 2, the biggest difference in the molecular structure of the passivation layer is that the halogen is substituted at the para position of the pyridine ring N, while in polyacrylonitrile, the para position of the pyridine ring N is a hydrogen atom. Verified by Gaussian calculation, the surface electron density of the M2 molecule is about 48 mV, far exceeding polyacrylonitrile (~18mV). This is because after the introduction of the highly electronegative halogen, the surface electron density increases, and an electrostatic potential is formed at the interface between the perovskite and the transport layer, thereby inhibiting the migration of halogen ions. Therefore, the device life of Example 1 is significantly increased compared to Comparative Example 2.

[0099] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A perovskite solar cell, characterized in that: The perovskite solar cell comprises a conductive substrate, a hole transport layer, a perovskite light absorption layer, an interface passivation layer, an electron transport layer and an electrode arranged in sequence; The interface passivation agent of the interface passivation layer includes at least one compound having a structure shown in general formula I; Formula I; Among them, R1, R 5+i are each independently selected from H or halogen, and R1, R 5+i At least one of them is selected from halogen; R2, R3, R4, and R5 are each independently selected from at least one of H, substituted or unsubstituted C1-C20 straight or branched alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 condensed ring aryl, substituted or unsubstituted C5-C30 heteroaryl, and substituted or unsubstituted C5-C30 condensed ring heteroaryl; i is an integer selected from 2 to 7, R 5+i Same or different; The substituted substituents include halogen; The halogen includes F, Cl, Br or I.

2. The perovskite solar cell according to claim 1, characterized in that Said R2, R3, R4, and R5 are each independently selected from H; The R1, R 5+i Each is independently selected from H or I.

3. The perovskite solar cell according to claim 1, characterized in that The interface passivator is selected from at least one of the following structural compounds; 、 、 、 、 。 4. The perovskite solar cell according to claim 1, characterized in that: The mass concentration of the interface passivator is 0.1-5 mg / mL.

5. The perovskite solar cell according to claim 1, characterized in that: The general structural formula of the material of the perovskite light absorbing layer is ABX3; Wherein, A is selected from CH3NH3 + 、CH2(NH3)2 + or Cs + Any one or a combination of at least two of the following: B is selected from Pb 2+ and / or Sn 2+ ; X is selected from I - Br - or Cl - Any one or a combination of at least two of the following: The thickness of the perovskite light absorbing layer is 300-900 nm; The material of the perovskite light absorbing layer includes a wide bandgap perovskite material, and the bandgap of the wide bandgap perovskite material is 1.65-1.75 eV.

6. The perovskite solar cell according to claim 1, characterized in that: The material of the electron transport layer includes C 60 SnO x or any one of 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline or a combination of at least two thereof; The thickness of the electron transport layer is 5-40 nm.

7. The perovskite solar cell according to claim 1, characterized in that: The material of the hole transport layer includes any one or a combination of at least two of nickel oxide, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine, [2-(9H-carbazole-9-yl)ethyl]phosphonic acid or [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid; The thickness of the hole transport layer is 5-30 nm.

8. The perovskite solar cell according to claim 1, characterized in that: The conductive substrate includes any one of an indium tin oxide conductive glass substrate, a fluorine-doped SnO2 conductive glass substrate or an aluminum-doped ZnO conductive glass substrate; The thickness of the conductive substrate is 20-200 nm; The electrode comprises a metal electrode; The thickness of the electrode is 80-120 nm.

9. A method for preparing a perovskite solar cell according to any one of claims 1 to 8, characterized in that: The preparation method comprises: The conductive substrate, the hole transport layer, the perovskite light absorption layer, the interface passivation layer, the electron transport layer and the electrode are stacked in sequence to obtain the perovskite solar cell.

10. The preparation method according to claim 9, characterized in that: The preparation method of the interface passivation layer comprises: Coating an interface passivator on the surface of the perovskite light absorbing layer, and annealing to obtain the interface passivation layer; The coating rotation speed is 1000-3000 rpm, and the time is 10-30 s; the annealing temperature is 80-140° C., and the time is 5-15 min.

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