A method for preparing a high-opening voltage perovskite solar cell

Abstract

The present application discloses a method for preparing a high-opening voltage perovskite solar cell, the preparation method comprising the configuration of a perovskite precursor and the preparation of a perovskite solar cell. The present application obtains a perovskite with a controllable band gap and stable at room temperature by regulating the types and ratios of monovalent cations and anions. By introducing additives into the perovskite precursor to eliminate organic cation vacancies and unsaturated coordinated lead cations, the passivation defects achieve a high opening voltage of more than 1100mV for the perovskite photovoltaic device, and improve the performance of the perovskite solar cell. This preparation method can not only promote the industrialization process of single-cell perovskite batteries, but also has great application prospects in full perovskite stacks, silicon / perovskite stacks, and compound film / perovskite stacks.

Description

Technical Field

[0001] The present application relates to the fields of perovskite precursor regulation, thin film preparation and photovoltaic technology, and specifically to a method for preparing a high-opening voltage perovskite solar cell. Background Art

[0002] Perovskite materials have excellent optoelectronic properties, such as adjustable band gap, high extinction coefficient, and bidirectional carrier transport. They have been favored by the academic community since the beginning of research. As a representative of the third generation of new high-efficiency photovoltaic materials, it took only ten years to achieve an increase in electrical conversion efficiency from 3.8% to 25%. Such a growth rate has never been seen in the history of photovoltaics. Therefore, perovskites are highly expected by the photovoltaic industry. At present, pure MAPbI3 or pure FAPbI3 are still the most mature ones. Although they have fully met the requirements of commercial applications in terms of efficiency, due to the limitations of optical band gap, crystallization phase or component characteristics, the hydrothermal stability of the pure MAPbI3 system is poor, and the long-term stability is worrying. It cannot be used as a candidate material for future industrialization. Pure FAPbI3 has a narrow band gap and a low theoretical opening voltage, so it can only be used in single-cell perovskite batteries. In addition, it is difficult to obtain a room temperature stable perovskite α phase with pure FAPbI3. Therefore, seeking more new perovskite systems with better optoelectronic properties, better long-term stability, high opening voltage, wide band gap, and no photoinduced phase change is the only way for future industrialization.

[0003] On the one hand, with the deepening of research, there are more and more ways to regulate the optoelectronic performance and long-term stability of perovskite devices. For example: interface modification, component engineering, additive engineering. On the one hand, mixed anions and cations are considered to be the most direct way of regulation in component engineering. Precise regulation of the components and content of A-site cations or X-site anions can not only stabilize the perovskite phase, inhibit photoinduced phase transition and improve long-term stability, but also the regulation of the band gap by mixed anions and cations can achieve the screening of perovskite systems with higher opening voltage and better performance, which is also a factor that must be considered in the future all-perovskite stacks or silicon / perovskite stacks and compound film / perovskite stacks. On the other hand, due to the unique defect tolerance of the perovskite structure, the inherent defects in the crystallization phase formation process of the perovskite film are also the main factors affecting its device performance. Defects can serve as charge carrier trap centers, ion migration paths, non-radiative recombination pathways or as water and oxygen erosion paths, which seriously affect the efficiency and long-term stability of perovskite solar cells. Therefore, adding suitable additives to the perovskite precursor to passivate defects can greatly improve the photoelectric conversion performance and long-term stability of perovskite solar cells. Summary of the invention

[0004] In order to solve the above problems, the present application provides a method for preparing a high-opening voltage perovskite solar cell.

[0005] The present invention discloses a method for preparing a high-opening voltage perovskite solar cell, comprising perovskite precursor configuration and perovskite solar cell preparation, wherein:

[0006] Perovskite precursor configuration includes: composition regulation, solvents and additives;

[0007] The preparation of perovskite solar cells includes: preparing a bottom electrode, preparing a first carrier transport layer, preparing a perovskite light absorption layer, preparing a second carrier transport layer, and preparing a top electrode.

[0008] Furthermore, in the preparation method, the perovskite precursor comprises three types of materials: A, B, and X, and the general structural formula is ABX3, wherein A is a monovalent cation: including but not limited to potassium K + , Cesium + , Rubidium Rb + FA + Or methylamine MA + One or more of the following, B is a divalent cation: including but not limited to lead Pb 2+ , Tin 2+ ,Ge 2+ One or more of, X is a halogen or a halogen-like anion: including but not limited to iodine I - , Br - , chlorine - or SCN - One or more of the .

[0009] Furthermore, the preparation method is characterized in that the perovskite precursor regulates the A-site cation Cs + The proportion of X-position anion Br is not less than 5%. - The ratio of A to B is not less than 5%, and the molar ratio of A to B is between 1:1 and 1:1.4.

[0010] Furthermore, in the preparation method, the perovskite precursor solvent uses any one or more of DMAc dimethylacetamide, DMF dimethylformamide, DMSO dimethyl sulfoxide, NMPN-methylpyrrolidone, GBLγ-butyrolactone high boiling point solvents and alcohols, amines, ethers, nitriles and other low boiling point solvents.

[0011] Furthermore, in the preparation method, the perovskite precursor additive includes at least one of pyridine, thiophene, phosphonic acid, alkyl acid, etc., which has a lone electron containing N, O, S functional groups and can fill organic cation vacancies and eliminate unsaturated lead cations.

[0012] Furthermore, in the preparation method, the perovskite solar cell comprises, from bottom to top, a bottom electrode, a first carrier transport layer, a perovskite light absorption layer, a second carrier transport layer, and a top electrode.

[0013] Furthermore, in the preparation method, the bottom electrode of the perovskite solar cell is a transparent conductive electrode, the first carrier transport layer and the second carrier transport layer have strong transmission capabilities for electrons or holes, including but not limited to one or more of semiconductor metal oxides, organic polymers, and organic small molecules, and the preparation method includes one or more of physical and chemical thin film preparation methods such as spin coating, atomic layer deposition, vacuum sputtering, chemical bath deposition, thermal spraying, immersion, and evaporation. The top electrode is a transparent conductive electrode or metal, including one or more of ITO, AZO, FTO, Au, Ag, Cu, and Al, and the preparation method includes at least one of screen printing, vacuum sputtering, vacuum evaporation, atomic layer deposition, and laser pulse deposition.

[0014] Furthermore, in the preparation method, the steps of preparing the perovskite solar cell include:

[0015] S01: Prepare a bottom electrode, characterized in that a transparent conductive electrode is prepared, and the thickness of the conductive film is 100-300nm.

[0016] S02: Prepare the first carrier transport layer, which has a strong transport capability for electrons or holes, including one or more of semiconductor metal oxide thin films, organic polymer thin films, and organic small molecule thin films. The preparation method includes one or more of physical and chemical thin film preparation methods such as spin coating, atomic layer deposition, vacuum sputtering, chemical bath deposition, thermal spraying, immersion, and evaporation.

[0017] S03: Prepare a perovskite light-absorbing layer, use the configured perovskite precursor, and adopt one of the methods including spin coating, blade coating, slit coating, and thermal spraying to prepare an intermediate phase film, with the film annealing temperature being 70-150° C. and the annealing time being 3-60 minutes.

[0018] S04: Prepare the second carrier transport layer, characterized by having a strong transport capability for electrons or holes, including one or more of semiconductor metal oxide thin films, organic polymer thin films, and organic small molecule thin films. The preparation method includes one or more of physical and chemical thin film preparation methods such as spin coating, atomic layer deposition, vacuum sputtering, chemical bath deposition, thermal spraying, immersion, and evaporation.

[0019] S05: Prepare the top electrode, the top electrode is selected from a transparent conductive electrode or metal, including one or more of ITO, AZO, FTO, Au, Ag, Cu, Al, and the preparation method includes at least one of the thin film preparation methods such as screen printing, vacuum sputtering, vacuum evaporation, atomic layer deposition, and laser pulse deposition.

[0020] Furthermore, in the method for preparing a perovskite solar cell, in step S04, the annealing method of the perovskite light absorbing layer film includes one-step and multi-step; the annealing environment includes but is not limited to air or an inert atmosphere with a relative humidity lower than 40%.

[0021] The present invention adopts a perovskite precursor with mixed A-site cations and mixed X-site anions, wherein the A-site cation Cs + The proportion of X-position anion Br is not less than 5%. - The ratio is not less than 5%. The molar ratio of A to B is between 1:1 and 1:1.4, and a perovskite with controllable bandgap width and stable at room temperature is obtained. By introducing lead cation additives that can fill organic cation vacancies and eliminate unsaturated coordination passivation defects into the precursor, the photoelectric conversion performance of perovskite solar cells is further improved. The photovoltaic device finally prepared obtains a high opening voltage of more than 1100mV on average. The perovskite solar cell involved in the present invention can not only promote the industrialization process of single-cell perovskite batteries, but also has great application prospects in full perovskite stacks, silicon / perovskite stacks and compound film / perovskite stacks. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 Schematic diagram of the structure of a high-opening voltage perovskite solar cell provided by an embodiment of the present invention;

[0024] Figure 2 It is the JV diagram of the perovskite solar cell of Examples 1 and 2 of Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The embodiment of the present invention provides a method for preparing a high-opening voltage perovskite solar cell, wherein the key steps include: configuring a perovskite precursor and preparing a perovskite solar cell, and the device structure is as follows: Figure 1 .

[0027] In the embodiment of the present application, the perovskite precursor comprises three types of materials A, B, and C, with a general formula of ABX3, wherein A is a monovalent cation: including potassium K + , Cesium + , Rubidium Rb + FA + Or methylamine MA + One or more of the following, B is a divalent cation: including lead Pb 2+ , Tin 2+ ,Ge 2+ One or more of, X is halogen and halogen-like anion: including iodine I - , Br - , chlorine - or SCN - One or more of the .

[0028] In the embodiment of the present application, the perovskite precursor A-site cation Cs + The proportion of is not less than 5%, the proportion of Br- at the X position is not less than 5%, and the molar ratio of A to B is between 1:1 and 1:1.4

[0029] In the embodiment of the present application, the perovskite precursor solvent uses any one or more of DMAc dimethylacetamide, DMF dimethylformamide, DMSO dimethyl sulfoxide, NMPN-methylpyrrolidone, GBLγ-butyrolactone high boiling point solvents and alcohols, amines, ethers, nitriles and other low boiling point solvents.

[0030] In the examples of the present application, the perovskite precursor additive includes at least one of pyridine, thiophene, phosphonic acid, alkyl acid, etc., which has a lone electron containing N, O, S functional groups and can fill organic cation vacancies and eliminate unsaturated lead cations. Specifically, Comparative Example 1 does not use additives, and Examples 1 and 2 use additives of different concentrations.

[0031] In the embodiment of the present application, the structure of the perovskite solar cell is as follows Figure 1 As shown, it is characterized in that, from bottom to top, there are a bottom electrode, a first carrier transport layer, a perovskite core absorption layer, a second carrier transport layer, and a top electrode.

[0032] Specifically, refer to Figure 1The device structure shown, the preparation steps of the perovskite solar cell include: S01: preparing the bottom electrode, preparing the transparent conductive electrode, the thickness of the conductive film is 100-300nm. S02: preparing the first carrier transport layer, which has a strong transmission ability for electrons or holes, including one or more of semiconductor metal oxide film, organic polymer film, and organic small molecule film. The preparation method includes one or more of physical and chemical film preparation methods such as spin coating, atomic layer deposition, vacuum sputtering, chemical bath deposition, thermal spraying, immersion, evaporation, etc.

[0033] S03: Prepare a perovskite light-absorbing layer, use the configured perovskite precursor, and adopt one of spin coating, blade coating, slit coating, and thermal spraying to prepare an intermediate film, the film annealing temperature is 70-150° C., and the annealing time is 3-60 minutes.

[0034] S04: Prepare the second carrier transport layer, which has a strong transport capability for electrons or holes, including one or more of semiconductor metal oxide thin films, organic polymer thin films, and organic small molecule thin films. The preparation method includes one or more of physical and chemical thin film preparation methods such as spin coating, atomic layer deposition, vacuum sputtering, chemical bath deposition, thermal spraying, immersion, and evaporation.

[0035] S05: Prepare the top electrode, the top electrode is selected from a transparent conductive electrode or metal, including one or more of ITO, AZO, FTO, Au, Ag, Cu, Al, and the preparation method includes at least one of the thin film preparation methods such as screen printing, vacuum sputtering, vacuum evaporation, atomic layer deposition, and laser pulse deposition.

[0036] In the method for preparing a perovskite solar cell, in step S03, the annealing method of the perovskite light absorbing layer film includes one-step and multi-step; the annealing environment includes air or an inert atmosphere with a relative humidity lower than 40%.

[0037] Comparative Example 1:

[0038] 1. Prepare the perovskite precursor: mix formamidinium iodide, cesium iodide, lead iodide, lead bromide, DMSO, and DMF to prepare a 1.2M perovskite precursor. The molar ratio of formamidinium iodide, cesium iodide, lead iodide, and NMP is 0.8:0.2:0.7:0.3 to obtain FA 0.8 Cs 0.2 PbI 2.4 Br 0.6 Yellow perovskite precursor solution.

[0039] 2. Prepare the bottom electrode: prepare a 200nm ITO film on a glass substrate as the bottom electrode.

[0040] 3. Prepare the first carrier transport layer, prepare 1mmol 2pacz / ethanol solution as the first carrier transport layer, and use 6000rpm / 30s, 100℃ annealing for 10min to prepare 2-5nm first carrier transport layer on the ITO bottom electrode.

[0041] 4. Prepare the perovskite light-absorbing layer by using a simple one-step anti-solvent and spin-coating the perovskite precursor to prepare the perovskite film. The spin-coating conditions are 5000rpm / 50s, and 200ul of anti-solvent is added in the 25th second. The perovskite light-absorbing layer is obtained by annealing at 130°C for 30min.

[0042] 5. Prepare the second carrier transport layer by preparing a 20 mg / ml chlorobenzene solution of PCBM. On the perovskite film cooled to room temperature after annealing, prepare a 40 nm thick PCBM transport layer at 1000 rpm / 30 s. Then take 120 ul of 0.5 mg / ml BCP isopropanol solution and spin coat an 8 nm thick BCP layer directly on the PCBM at 5000 rpm / 30 s.

[0043] 6. Prepare the top electrode by vacuum thermal evaporation at 5x10 -4 A 100nm thick Au layer was prepared under a vacuum of 1.0 Pa.

[0044] The JV curve of Comparative Example 1 is as follows: Figure 2 As shown, the open circuit voltage is lower at Voc = 1043mv, and the short circuit current Jsc = 19.9mA / cm 2 , Fill factor FF = 78%, Photoelectric conversion efficiency PCE = 16.2%

[0045] Embodiment 1:

[0046] 1. Prepare the perovskite precursor, take formamidinium iodide, cesium iodide, lead iodide, lead bromide and additive 4,4-(hexafluoroisopropyl) diphthalic anhydride (6-FDA), DMSO, DMF and mix them evenly to prepare a 1.2M perovskite precursor. The molar ratio of formamidinium iodide, cesium iodide, lead iodide, lead bromide and 6-FDA is 0.8:0.2:0.7:0.3:0.001, and FA is obtained. 0.8 Cs 0.2 PbI 2.4 Br 0.6 Yellow perovskite precursor solution with +0.1% 6-FDA.

[0047] 2. Prepare the bottom electrode: prepare a 200nm ITO film on a glass substrate as the bottom electrode.

[0048] 3. Prepare the first carrier transport layer, prepare 1mmol 2pacz / ethanol solution as the first carrier transport layer, and use 6000rpm / 30s, 100℃ annealing for 10min to prepare 2-5nm first carrier transport layer on the ITO bottom electrode.

[0049] 4. Prepare the perovskite layer by using a simple one-step anti-solvent and spin coating the perovskite precursor to prepare the perovskite film. The spin coating conditions are 5000rpm / 50s, 200ul of anti-solvent is added in the 25th second, and the perovskite light-absorbing layer is obtained by annealing at 130°C for 30min.

[0050] 5. Prepare the second carrier transport layer by preparing a 20 mg / ml chlorobenzene solution of PCBM. After annealing and cooling to room temperature, prepare a 40 nm thick PCBM at 1000 rpm / 30 s. Then take 120 ul of 0.5 mg / ml BCP isopropanol solution and spin coat a 8 nm thick BCP layer directly on the PCBM at 5000 rpm / 30 s.

[0051] 6. Prepare the top electrode by vacuum thermal evaporation at 5x10 -4 A 100 nm thick Au layer was prepared under a vacuum degree of 1.5 Pa.

[0052] The JV curve of the device in Example 1 is as follows: Figure 2 As shown, the open circuit voltage Voc = 1084mV, the short circuit current Jsc = 19.4mA / cm 2 , fill factor FF = 77%, photoelectric conversion efficiency PCE = 16.3%. Due to the addition of additives, the passivation defects, the open circuit voltage is increased by 41 mV compared with comparative example 1.

[0053] Embodiment 2:

[0054] 1. Prepare the perovskite precursor, take formamidinium iodide, cesium iodide, lead iodide, lead bromide and additive 4,4-(hexafluoroisopropyl) diphthalic anhydride (6-FDA), DMSO, DMF and mix them evenly to prepare a 1.2M perovskite precursor. The molar ratio of formamidinium iodide, cesium iodide, lead iodide, lead bromide and 6-FDA is 0.8:0.2:0.7:0.3:0.002, and FA is obtained. 0.8 Cs 0.2 PbI 2.4 Br 0.6 Yellow perovskite precursor solution with +0.2% 6-FDA.

[0055] 2. Prepare the bottom electrode: prepare a 200nm ITO film on a glass substrate as the bottom electrode.

[0056] 3. Prepare the first carrier transport layer, prepare 1mmol 2pacz / ethanol solution as the first carrier transport layer, and use 6000rpm / 30s, 100℃ annealing for 10min to prepare 2-5nm first carrier transport layer on the ITO bottom electrode.

[0057] 4. Prepare the perovskite layer by using a simple one-step anti-solvent and spin coating the perovskite precursor to prepare the perovskite film. The spin coating conditions are 5000rpm / 50s, 200ul of anti-solvent is added in the 25th second, and the perovskite light-absorbing layer is obtained by annealing at 130°C for 30min.

[0058] 5. Prepare the second carrier transport layer by preparing a 20 mg / ml chlorobenzene solution of PCBM. After annealing and cooling to room temperature, prepare a 40 nm thick PCBM at 1000 rpm / 30 s. Then take 120 ul of 0.5 mg / ml BCP isopropanol solution and spin coat a 8 nm thick BCP layer directly on the PCBM at 5000 Rpm / 30 s.

[0059] 6. Prepare the top electrode by vacuum thermal evaporation at 5x10 -4 A 100nm thick Au layer was prepared under a vacuum of 1.0 Pa.

[0060] The JV curve of the device in Example 2 is as follows: Figure 2 As shown, the open circuit voltage Voc = 1127mV, the short circuit current Jsc = 19.3mA / cm 2 , fill factor FF = 76%, photoelectric conversion efficiency PCE = 16.7%, after optimizing the dosage of additives, the opening voltage is further improved, which is 84mV higher than that of control example 1, and a high opening voltage of more than 1100mV is obtained. The photoelectric conversion performance is further improved. The preparation method of a high opening voltage perovskite solar cell described in this application can not only promote the industrialization process of single-cell perovskite cells, but also has great application prospects in full perovskite stacks, silicon / perovskite stacks, and compound film / perovskite stacks.

[0061] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for preparing a high-opening voltage perovskite solar cell, characterized in that: The perovskite solar cell preparation steps include: S01: Prepare a bottom electrode, prepare a transparent conductive electrode, and the thickness of the conductive film is 100-300nm; S02: preparing a first carrier transport layer having a strong transport capability for electrons or holes, including one or more of a semiconductor metal oxide film, an organic polymer film, and an organic small molecule film; the preparation method includes one or more of spin coating, atomic layer deposition, vacuum sputtering, chemical bath deposition, thermal spraying, immersion, and evaporation; S03: Prepare a perovskite light-absorbing layer, use the configured perovskite precursor, and use one of spin coating, blade coating, slit coating, and thermal spraying to prepare an intermediate phase film, the film annealing temperature is 70-150°C, and the annealing time is 3-60 minutes; wherein, formamidine iodine, cesium iodide, lead iodide, lead bromide and additives 4,4-(hexafluoroisopropyl) diphthalic anhydride (6-FDA), DMSO, and DMF are mixed to form the perovskite precursor; S04: preparing a second carrier transport layer, which has a strong transport capability for electrons or holes, including one or more of a semiconductor metal oxide film, an organic polymer film, and an organic small molecule film; the preparation method includes one or more of spin coating, atomic layer deposition, vacuum sputtering, chemical bath deposition, thermal spraying, immersion, and evaporation physical and chemical film preparation methods; S05: Preparation of the top electrode. The top electrode is a transparent conductive electrode or a metal electrode with a thickness of 80-300nm. It includes one or more of ITO, AZO, FTO, Au, Ag, Cu, and Al. The preparation method includes at least one of screen printing, vacuum sputtering, vacuum evaporation, atomic layer deposition, and laser pulse deposition.

2. The preparation method according to claim 1, characterized in that: In the step S03 of preparing the perovskite solar cell, the annealing of the perovskite light absorbing layer film includes one step and multiple steps; the annealing environment includes air or an inert atmosphere with a relative humidity lower than 40%.

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