Modified SnO2 sol, perovskite solar cell and preparation method
Through the combined treatment of ultrasonic and alkaline sources and NaClO passivation of oxygen vacancies, the problem of poor storage stability of SnO2 sol is solved, and the conversion efficiency and stability of perovskite solar cells are improved.
Patent Information
- Application Number
- CN202510324672.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-19
- Publication Date
- 2025-06-17
AI Technical Summary
The SnO2 sol prepared by traditional methods has poor storage stability, resulting in low conversion efficiency and long-term stability of perovskite solar cells.
By combining ultrasonic and alkaline source treatment, the hydroxyl radical and electric double layer are generated, and the reservoir stability is increased by generating a hydroxyl radical and an electric double layer. In addition, NaClO is added to passivate the surface oxygen vacancies, reduce the generation of oxygen vacancies, inhibit iodine diffusion, and reduce the degradation level of the material at the interface.
The reservoir stability and conductivity of SnO2 sol are improved, the interface defects of perovskite solar cells are reduced, and the photoelectric conversion efficiency and long-term stability are improved.
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Figure CN120166841A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of perovskite solar cells, and particularly to a modified SnO2 sol, an electron transport layer material, a perovskite solar cell, and a preparation method thereof. Background Art
[0002] In recent years, organic-inorganic lead halide perovskite solar cells have attracted extensive attention. The power conversion efficiency (PCE) of perovskite solar cells has rapidly increased from 3.8% to 26.7%. The rapid increase in efficiency is mainly attributed to the superior photovoltaic properties of lead halide perovskites, such as extremely high light absorption coefficients and long carrier lifetimes. High-efficiency perovskite solar cells typically use electron transport layers (ETLs) / hole blocking layers and hole transport layers (HTLs) / electron blocking layers to separate and collect photo-generated carriers generated in the perovskite absorber. These layers are crucial for achieving high-efficiency cells because they can prevent severe carrier recombination at the interfaces, and carrier recombination may determine the open-circuit voltage (Voc) and fill factor (FFs) of the solar cell.
[0003] Tin dioxide (SnO2) has a very high native mobility, up to 240 cm 2 / (V·s), and is an ideal participant for effectively transferring electrons. In addition, SnO2 has a sufficiently wide bandgap, excellent visible light transmittance, and the valence band reaches its maximum at a sufficiently deep position, which helps SnO2 have the ability to block holes during the electron transfer process and avoid electron-hole recombination. In addition, SnO2 is insensitive to ultraviolet light, thus avoiding instability caused by photocatalytic activity. Based on the above advantages, SnO2 has been proven to be an ideal candidate material for the electron transport layer (ETLs) in perovskite solar cells (PSCs). So far, using SnO2 as ETLs has achieved a record power conversion efficiency (PCE) for PSCs, and it also has greater breakthrough potential in terms of cell performance compared to other candidate materials. However, using traditional synthesis methods, the storage stability of the obtained tin dioxide sol has problems. The tin dioxide sol often settles in 1-2 days, and the tin dioxide sol stored for a long time is prone to generating numerous oxygen vacancy defects due to random motion. A relatively high oxygen vacancy concentration may increase the positive charge of Sn atoms and lead to an increase in the Pb-I bond length at the perovskite / tin dioxide interface. This less stable chemical bond will promote the formation of iodine interstitial atoms and accelerate the degradation of device performance, which greatly reduces the conversion efficiency and long-term stability of perovskite solar cells. Summary of the Invention
[0004] In view of this, the present disclosure provides a modified SnO2 sol, a perovskite solar cell and a preparation method thereof, which solve the problem that the SnO2 sol prepared by the existing method hinders the electron transport due to the storage stability problem, thereby greatly reducing the conversion efficiency and long-term stability of the perovskite solar cell.
[0005] To achieve the above-mentioned invention purpose, the inventive concept of the modified SnO2 sol described in the present disclosure is as follows:
[0006] By using the combined treatment of ultrasonic and alkali source, hydroxyl radicals and hydrogen radicals can be obtained after ultrasonic treatment. The hydroxyl radicals stably combine with the Sn atoms in SnO2, effectively blocking the agglomeration of the SnO2 colloidal solution. And during the ultrasonic process, due to the action of the alkali source, a double electric layer will be formed on tin dioxide, and then due to the reason of electrostatic repulsion, it can stably exist in the colloidal solution. Therefore, the storage stability of the SnO2 sol can be effectively improved by the combined treatment of ultrasonic and alkali source; in addition, when the SnO2 colloidal solution is stored for a long time, oxygen vacancy defects are likely to be generated due to molecular thermal motion. The present disclosure adopts the treatment method of adding NaClO. NaClO can passivate the surface oxygen vacancies, and Cl ions can combine with the oxygen vacancies. The prepared tin dioxide thin film inhibits the diffusion of iodine from the perovskite to the ETL layer, effectively reducing the degradation level of the perovskite material at the interface.
[0007] Based on the above inventive concept, on the first aspect, the modified SnO2 sol provided by the present disclosure has a preparation method including:
[0008] Preparing or obtaining the SnO2 sol;
[0009] Adding an alkali source to the SnO2 sol and then performing ultrasonic dispersion to obtain the modified SnO2 sol.
[0010] In the present disclosure and possible embodiments, the ultrasonic power of the ultrasonic dispersion is 500-1200 W, the ultrasonic frequency is 15-35 KHz, and the ultrasonic dispersion time is 5-20 min.
[0011] In the present disclosure and possible embodiments, the preparation method further includes:
[0012] After the ultrasonic dispersion is completed, adding NaClO to the dispersion system and continuing the ultrasonic dispersion to obtain the modified SnO2 sol.
[0013] In the present disclosure and possible embodiments, the method for preparing the SnO2 sol includes:
[0014] Add glacial acetic acid and ammonia water to the dissolution solution of SnCl4·5H2O, and the volume ratio of the glacial acetic acid to the ammonia water is 1:1 to 1:3; after the system cools down, heat it at 100°C to 150°C for 1 h to 3 h for reaction, and after the reaction product is centrifuged, washed and dissolved in water, the SnO2 sol is obtained.
[0015] In the present disclosure and possible embodiments, the base source is KOH, NaOH or LiOH.
[0016] In a second aspect, the perovskite solar cell includes, from bottom to top in sequence:
[0017] a conductive glass, an electron transport layer, a perovskite light absorption layer, a hole transport layer and a metal electrode;
[0018] The material of the electron transport layer is the modified SnO2 sol according to any one of the first aspect.
[0019] In the present disclosure and possible embodiments, the thickness of the electron transport layer is 30 to 100 nm.
[0020] In the present disclosure and possible embodiments, the conductive glass is ITO glass or FTO glass; and / or,
[0021] The material of the perovskite light absorption layer is selected from MAPbI3, FAPbI3, CsPbI3, (FAPbI3) 0.87 (MAPbBr3) 0.13 , Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 )、FA 0.83 Cs 0.17 PbI3; and / or,
[0022] The material of the hole transport layer is 2,2,7,7-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9-spirobifluorene (Spiro-OMeTAD) or poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA); and / or,
[0023] The material of the metal electrode is gold, silver or copper.
[0024] In a third aspect, a method for preparing the perovskite solar cell includes:
[0025] Spin-coat the modified SnO2 sol according to any one of the first aspect on a substrate and anneal it to obtain an electron transport layer;
[0026] A perovskite light-absorbing layer, a hole transport layer, and a metal electrode are sequentially prepared on the electron transport layer to obtain the perovskite solar cell.
[0027] In the present disclosure and possible embodiments, the annealing temperature is 150°C to 180°C, and the time is 20 min to 40 min; and / or,
[0028] The spin coating speed is 3000 - 5000 rpm, the spin coating acceleration is 1000 - 2000 rpm / s, and the spin coating time is 30 s.
[0029] The beneficial effects of the present invention are:
[0030] The modified SnO₂ sol of the present invention reduces the surface roughness of the tin dioxide thin film through ultrasonic treatment, improves the conductivity of the tin dioxide transport layer, and since the hydroxyl radicals obtained after ultrasonic treatment bind to the Sn atoms in SnO₂, the agglomeration phenomenon of the SnO₂ colloidal solution is effectively blocked, the Sn defects of tin dioxide are passivated, and during the ultrasonic process, due to the action of an alkali source (such as KOH), a double electric layer will be formed on tin dioxide, and then due to the reason of electrostatic repulsion, it can stably exist in the solution. Therefore, the storage stability of the SnO₂ sol can be effectively improved by the combined treatment of ultrasonic and alkali source. Further, by adding NaClO, the surface oxygen vacancies can be passivated and the generation of oxygen vacancies can be reduced. The Cl ions can combine with the oxygen vacancies, and the prepared tin dioxide thin film inhibits the diffusion of iodine from the perovskite to the ETL layer, effectively reducing the degradation level of the perovskite material at the interface. Description of the Drawings
[0031] The drawings here are incorporated into the specification and form a part of this specification. These drawings show embodiments consistent with the present disclosure and are used together with the specification to illustrate the technical solutions of the present disclosure.
[0032] Figure 1 It is a device diagram of the perovskite solar cell obtained in Example 1 of the present disclosure based on the synthesized C - SnO₂ electron transport layer;
[0033] Figure 2 It is the XRD diagram of the C - SnO₂ electron transport layer of the comparative example of the present disclosure and the T - SnO₂ electron transport layer of Example 1;
[0034] Figure 3 In it, a / b is the X-ray photoelectron spectroscopy (XPS) diagram of the C - SnO₂ electron transport layer of the comparative example of the present disclosure and the T - SnO₂ electron transport layer of Example 1 respectively based on Sn and O elements;
[0035] Figure 4 It is the current density - voltage curve diagram of the perovskite solar cells obtained in the comparative example and Example 1 of the present disclosure;
[0036] Figure 5 It is the current density-voltage curve graph of the perovskite solar cells obtained in Example 1 and Example 5 of the present disclosure;
[0037] Figure 6 It is the atomic force microscope AFM (Figure a / c) and KPFM schematic diagram (Figure b / d) of the C-SnO2 electron transport layer in the comparative example of the present disclosure and the T-SnO2 electron transport layer in Example 1. Detailed implementation manners
[0038] The following will detail various exemplary embodiments, features, and aspects of the present disclosure with reference to the accompanying drawings. The same reference numerals in the drawings denote elements with the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.
[0039] If there is no special indication, all steps of the present invention can be carried out sequentially or randomly. For example, the method includes steps 1 and 2, indicating that the method may include steps 1 and 2 carried out sequentially, or steps 2 and 1. For example, the method may further include step 3, indicating that step 3 can be added to the method in any order.
[0040] To solve the problems in the background art, for the modified SnO2 sol described in various embodiments of the present disclosure, its preparation method is:
[0041] Prepare or obtain SnO2 sol, add an alkali source to the SnO2 sol and then perform ultrasonic dispersion for a set time to obtain the modified SnO2 sol; wherein, the ultrasonic power is 500 - 1200W, the ultrasonic frequency is 15 - 35KHz, and the set time is 5 - 20min.
[0042] Preferably, after the set time ends, continue to add NaClO solution and continue ultrasonic dispersion for 5min to obtain the modified SnO2 sol.
[0043] In a specific embodiment, the preparation method of the modified SnO2 sol includes the following steps:
[0044] (1) Dissolve 5g of SnCl4·5H2O in 50mL of ethylene glycol and stir for 5 - 15h.
[0045] (2) Take 10ml of the above solution and transfer it to a round-bottom flask, add 10ml of ethylene glycol, stir and then add a total of 4ml of a mixed solution of glacial acetic acid and ammonia water, and the volume ratio of glacial acetic acid to ammonia water is 1:1 - 1:3.
[0046] (3) After cooling to room temperature, place the round-bottom flask in an oil bath and heat it at 100 - 150°C for 1h - 3h to carry out the reaction.
[0047] (4) After the reaction is completed and cooled, transfer the reactants to a centrifuge tube. The centrifugation speed is 5000 r / s, and the centrifugation time is 20 minutes. After centrifugation, remove the supernatant, add 20 ml of ethanol, dissolve it by ultrasonic treatment and then centrifuge again. Repeat this process twice. Finally, add water and dissolve it by ultrasonic treatment to obtain a SnO2 sol with a mass concentration of 2-5%.
[0048] (5) Add an alkali source to the above SnO2 sol and dissolve and disperse it by ultrasonic treatment to obtain a C-SnO2 solution. The amount of the alkali source added can be 2-12.5 mg per milliliter of the SnO2 sol.
[0049] (6) Continuously add a NaClO solution to the C-SnO2 solution and disperse it by ultrasonic treatment for 5 min to obtain a modified SnO2 sol; wherein the mass concentration of the NaClO solution is 5%-10%, and the volume is 50-200 ul.
[0050] In a specific embodiment, the alkali source is KOH, NaOH or LiOH;
[0051] In a specific embodiment, the perovskite solar cell includes, from bottom to top, a conductive glass, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer and a metal electrode. Among them, the electron transport layer is prepared from the modified SnO2 sol described in the present disclosure, and the thickness of the electron transport layer is 30-100 nm.
[0052] In a specific embodiment, the conductive glass is ITO glass or FTO glass;
[0053] The material of the perovskite light-absorbing layer is selected from MAPbI3, FAPbI3, CsPbI3, (FAPbI3) 0.87 (MAPbBr3) 0.13 , Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 )、FA 0.83 Cs 0.17 PbI3;
[0054] The material of the hole transport layer is 2,2,7,7-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9-spirobifluorene (Spiro-OMeTAD) or poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA);
[0055] The material of the metal electrode is gold, silver or copper.
[0056] In a specific embodiment, the preparation method of the perovskite solar cell comprises the following steps:
[0057] (1) Spin-coat the SnO2 sol on a substrate and perform annealing to obtain an electron transport layer;
[0058] (2) Sequentially prepare a perovskite light-absorbing layer, a hole transport layer, and a metal electrode on the electron transport layer to obtain the perovskite solar cell.
[0059] In a specific embodiment, the annealing temperature is 150°C to 180°C, and the time is 20 min to 40 min.
[0060] In a specific embodiment, the spin-coating speed is 3000 - 5000 rpm, the spin-coating acceleration is 1000 - 2000 rpm / s, and the spin-coating time is 30 s.
[0061] The following are the preferred embodiments of the present disclosure.
[0062] Unless otherwise specified, the reagents, methods, and equipment used in the embodiments are conventional reagents, methods, and equipment in the technical field.
[0063] Example 1
[0064] In this Example 1, modified SnO2 sols with different ultrasonic times were prepared and then applied to the electron transport layer of the perovskite solar cell. Among them, the structure of the perovskite solar cell from bottom to top is: ITO glass / electron transport layer (T-SnO2) / perovskite light-absorbing layer (Perovskite) / hole transport layer (Spiro-OMeTAD) / metal electrode (Ag).
[0065] I. Preparation of the modified SnO2 sol. The specific preparation steps are as follows:
[0066] (1) Dissolve 5 g of SnCl4·5H2O in 50 mL of ethylene glycol and stir for 5 - 15 h.
[0067] (2) Take 10 ml of the above solution and transfer it to a round-bottom flask, add 10 ml of ethylene glycol, stir, and then add 2 ml of glacial acetic acid and ammonia sol. The volume ratio of glacial acetic acid to ammonia water is 1:2.
[0068] (3) After cooling to room temperature, place the round-bottom flask in an oil bath and heat it at 150°C for 1 h for reaction.
[0069] (4) After the reaction is completed and cooled, transfer the reactants to a centrifuge tube. The centrifugation speed is 5000 r / s, and the centrifugation time is 20 minutes. After centrifugation, remove the supernatant, add 20 ml of ethanol, dissolve it by ultrasonic treatment and then centrifuge again. Repeat this process twice. Finally, add water and dissolve it by ultrasonic treatment to obtain a SnO2 sol with a mass concentration of 5%.
[0070] (5) Add a KOH solution with a concentration of 1 mg / ml and a volume of 11 ul to the above SnO2 sol and dissolve and disperse it by ultrasonic treatment to obtain a C-SnO2 solution. The ultrasonic power is 800 - 1000 W, the ultrasonic frequency is 20 - 30 KHz, and the ultrasonic time is 5 min.
[0071] (6) Continuing in the C-SnO2 solution, add a NaClO solution with a mass concentration of 8% in an amount of 100 ul per milliliter of C-SnO2 and continue ultrasonic dispersion for 5 min to obtain the modified SnO2 sol of Example 1.
[0072] II. Preparation of perovskite solar cells. The specific preparation steps are as follows:
[0073] (1) Substrate cleaning:
[0074] Select ITO conductive glass as the substrate, with a specification of 20 mm * 20 mm. Place it in a beaker and ultrasonically clean it in deionized water and ethanol for 20 min each. After ultrasonic treatment, dry the ITO substrate with nitrogen, and then treat it with an ozone generator for 10 min to enhance the surface adhesion.
[0075] (2) Preparation of the T-SnO2 electron transport layer:
[0076] Dilute the modified SnO2 sol of Example 1 into a solution with a concentration of 25 mg / ml. Use a pipette to aspirate 150 μL and spin-coat it on the ITO substrate. The spin-coating conditions are: rotation speed 4000 rpm, acceleration 2000 rpm / s, and spin-coating time 30 s. Then anneal it on a hot plate at 180 °C for 20 minutes. After annealing is completed, obtain the T-SnO2 electron transport layer and transfer it to the glove box for standby.
[0077] (3) Preparation of the perovskite layer:
[0078] Weigh out 779.09 mg of PbI2, add 1235 ul of DMF and 65 ul of DMSO, and then place it in an oscillator overnight;
[0079] Weigh out 90.3 mg of FAI and 18.434 mg of MACI, and add 1500 ul of IPA, and perform oscillation treatment;
[0080] Under the condition of a nitrogen atmosphere glove box, 40 μL of PbI2 solution was aspirated and spin-coated on the ITO substrate of the T-SnO2 electron transport layer, and annealed at 70 °C for 1 min to obtain a PbI2 thin film; the spin-coating speed was 1500 rpm, the acceleration was 3000 rpm / s, and the spin-coating time was 30 s.
[0081] After the PbI2 thin film was cooled to room temperature, 50 μL of the FAI mixed solution was aspirated and spin-coated on the PbI2 thin film, and then quickly transferred to an air atmosphere with 30% - 40% humidity, and annealed at 150 °C for 20 min to obtain a perovskite light-absorbing layer; the spin-coating speed was 1500 rpm, the acceleration was 2000 rpm / s, and the spin-coating time was 30 s.
[0082] (4) Preparation of the Spiro-OMeTAD hole transport layer:
[0083] 86.76 mg of 2,2,7,7-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9-spirobifluorene (Spiro-OMeTAD), 21 μL of lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), and 35.8 μL of tert-butylpyridine (TBP) were dissolved in 1.2 mL of chlorobenzene solvent and stirred for 30 min to obtain a Spiro solution. Subsequently, 40 μL of the Spiro solution was spin-coated on the surface of the perovskite light-absorbing layer to obtain a Spiro-OMeTAD hole transport layer; the spin-coating speed was 3000 rpm, the acceleration was 2000 rpm / s, and the time was 30 s.
[0084] (5) Deposition of the metal electrode Ag:
[0085] Using the vacuum thermal evaporation method, 80 nm thick silver Ag was evaporated as the metal electrode on the hole transport layer through a mask plate, and finally a complete perovskite solar cell device was obtained ( Figure 1 ).
[0086] Example 2
[0087] The modified SnO2 sol and perovskite solar cell were prepared according to the same method as in Example 1, except that a KOH solution with a concentration of 1 mg / ml was added to the prepared SnO2 sol, and the ultrasonic time for ultrasonic dissolution and dispersion was changed to 10 min, and after ultrasonic treatment, no NaClO solution was added, and the modified SnO2 sol of this Example 2 was directly obtained.
[0088] Example 3
[0089] The modified SnO2 sol and perovskite solar cells were prepared in the same manner as in Example 1, except that a KOH solution with a concentration of 1 mg / ml was added to the prepared SnO2 sol, the ultrasonic time for ultrasonic dissolution and dispersion was changed to 15 min, and no NaClO solution was added after ultrasonic treatment, and the modified SnO2 sol of this Example 3 was directly obtained.
[0090] Example 4
[0091] The modified SnO2 sol and perovskite solar cells were prepared in the same manner as in Example 1, except that a KOH solution with a concentration of 1 mg / ml was added to the prepared SnO2 sol, the ultrasonic time for ultrasonic dissolution and dispersion was changed to 20 min, and no NaClO solution was added after ultrasonic treatment, and the modified SnO2 sol of this Example 4 was directly obtained.
[0092] Comparative Example
[0093] Take the tin dioxide of commercial manufacturer's bath sunlight energy, the batch number is 307005, and dilute the tin dioxide by 1:4, and then apply it to the perovskite solar cell. The preparation method of this perovskite solar cell is the same as that of Example 1.
[0094] The above-mentioned examples and comparative examples are analyzed and tested as follows:
[0095] (1) XRD comparative test of the electron transport layer:
[0096] As Figure 2 shown, the XRD test was carried out on the T-SnO2 electron transport layer obtained in Example 1 and the C-SnO2 electron transport layer obtained in the comparative example. The test results prove that the crystallinity of the modified SnO2 in Example 1 is better than that of the SnO2 in the comparative example, indicating that the combined action of ultrasonic and alkali solution increases the crystallinity of SnO2.
[0097] (2) X-ray photoelectron spectroscopy comparative test of the electron transport layer:
[0098] The X-ray photoelectron spectroscopy test was carried out on the T-SnO2 electron transport layer obtained in Example 1 and the C-SnO2 electron transport layer obtained in the comparative example. The Sn 3d and O1s XPS spectra were analyzed respectively. As Figure 3 shown in a\b in, the modified SnO2 sol in Example 1 shows that the Sn binding energy shifts to a lower value. Compared with the commercially available SnO2 sol in the comparative example, it indicates that the electron cloud density is higher, so it has excellent conductivity.
[0099] (3) SnO2 energy level spectrum comparison:
[0100] The O1s core level spectra of the commercially available bath sunlight energy and the SnO2 film in Example 1 are fromFigure 3 It can be seen that the peak at approximately 529.6 eV can be decomposed into two components. Although one peak corresponds to the intrinsic metal-oxygen bond, there is an obvious peak at approximately 530.8 eV, which can be attributed to hydroxyl ions (-OH) and oxygen vacancies (O V ). Compared with the SnO2 film of Example 1, the concentration of hydroxyl ions (-OH) in the commercially available SnO2 is higher, which will lead to an increase in the defect density, thereby reducing the conductivity of the commercially available tin dioxide SnO2.
[0101] (4) Comparison of the photoelectric conversion efficiency of perovskite solar cells:
[0102] The device photoelectric conversion efficiency of the perovskite solar cells of Example 1 and the comparative example was tested, and the cell area was 0.04 cm 2 , and the test conditions were standard simulated sunlight AM 1.5 under a nitrogen environment.
[0103] The reverse scan of the optimal short-circuit current-open circuit voltage is as Figure 4 shown. Compared with the perovskite solar cell of Comparative Example 1, the device photoelectric conversion efficiency of the perovskite solar cell of Example 1 was increased from 24.33% to 25.16%, and the average open circuit voltage was increased by 20 mV. This is mainly due to the reduction of interface defects and the improvement of charge extraction efficiency, which reduces energy loss.
[0104] (5) Comparison of the PCE of the perovskite solar cells of Example 1 and Example 5:
[0105] The reverse scan of the optimal short-circuit current-open circuit voltage of the two is as Figure 5 shown. Compared with the perovskite solar cell of Example 5, the device photoelectric conversion efficiency of the perovskite solar cell of Example 1 was increased from 24.01% to 25.16%, and the average fill factor was increased by 2%. This is mainly due to the oxidation of SnO2 by the strong oxidant NaClO, resulting in fewer oxygen vacancies on the surface of SnO2, thereby improving its fill factor.
[0106] (6) Comparison of the atomic force microscope images of the electron transport layer films:
[0107] Figure 6Atomic force microscopy (AFM) images (Figs. a / c) and Kelvin probe force microscopy (KPFM) schematic diagrams (Figs. b / d) of SnO2 showing bath sunlight energy and the T-SnO2 thin film of Example 1 are presented. Due to the steric effect on the SnO2 surface, the aggregation of nanoparticles after thermal annealing is reduced. Therefore, the T-SnO2 thin film exhibits a lower root mean square (RMS) roughness (0.56 nm) compared to commercially available SnO2 (1.64 nm). Meanwhile, Kelvin probe force microscopy (KPFM) measurements reveal a difference in surface potential. The surface of the T-SnO2 thin film exhibits a considerably high average surface potential (481 mV) compared to the commercially available SnO2 thin film (300 mV). This elevated surface potential in the T-SnO2 thin film, combined with its enhanced electron mobility, is expected to facilitate carrier transport in perovskite solar cells (PSCs).
[0108] It can be understood that, without violating the principle logic, the above-mentioned various method embodiments mentioned in the present disclosure can be combined with each other to form combined embodiments. Due to space limitations, the present disclosure will not elaborate further.
[0109] The various embodiments of the present disclosure have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of the technology in the market, or to enable other ordinary skilled persons in the technical field to understand the embodiments disclosed herein.
Claims
1. A modified SnO2 sol, characterized in that: The preparation method thereof comprises: Prepare or obtain SnO2 sol; The modified SnO2 sol is obtained by adding an alkali source into the SnO2 sol and then performing ultrasonic dispersion.
2. The modified SnO2 sol according to claim 1, characterized in that: The ultrasonic power of the ultrasonic dispersion is 500-1200W, the ultrasonic frequency is 15-35KHz, and the ultrasonic dispersion time is 5-20min.
3. The modified SnO2 sol according to claim 1 or 2, characterized in that: The preparation method further comprises: After the ultrasonic dispersion is completed, NaClO is added to the dispersion system and the ultrasonic dispersion is continued to obtain the modified SnO2 sol.
4. The modified SnO2 sol according to claim 3, characterized in that: The method for preparing the SnO2 sol comprises: Add glacial acetic acid and ammonia water to the SnCl4·5H2O solution, wherein the volume ratio of the glacial acetic acid to the ammonia water is 1:1 to 1:3; after the system is cooled, heat at 100°C to 150°C for 1h to 3h to react, and the reaction product is centrifuged, washed and dissolved in water to obtain the SnO2 sol.
5. The modified SnO2 sol according to claim 4, characterized in that: The alkali source is KOH, NaOH or LiOH.
6. A perovskite solar cell, characterized in that: Its structure from bottom to top includes: Conductive glass, electron transport layer, perovskite light absorption layer, hole transport layer and metal electrode; The material of the electron transport layer is the modified SnO2 sol as described in any one of claims 1-5.
7. The perovskite solar cell according to claim 6, characterized in that: The thickness of the electron transport layer is 30-100 nm.
8. The perovskite solar cell according to claim 6 or 7, characterized in that: The conductive glass is ITO glass or FTO glass; and / or, The material of the perovskite light absorbing layer is selected from MAPbI3, FAPbI3, CsPbI3, (FAPbI3) 0.87 (MAPbBr3) 0.13 , Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 ), FA 0.83 Cs 0.17 One of PbI3; and / or, The material of the hole transport layer is 2,2,7,7-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9-spirobifluorene (Spiro-OMeTAD) or poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA); and / or, The material of the metal electrode is gold, silver or copper.
9. A method for preparing a perovskite solar cell, characterized in that: include: Spin coating the modified SnO2 sol according to any one of claims 1 to 5 on a substrate, and annealing to obtain an electron transport layer; A perovskite light absorbing layer, a hole transport layer and a metal electrode are sequentially prepared on the electron transport layer to obtain the perovskite solar cell.
10. A method for preparing a perovskite solar cell, characterized in that: The annealing temperature is 150° C. to 180° C., and the annealing time is 20 min to 40 min; and / or, The spin coating speed is 3000-5000 rpm, the spin coating acceleration is 1000-2000 rpm / s, and the spin coating time is 30 s.