Perovskite precursor solution based on the addition of 1-thioglycerol and solar cells

Abstract

The present invention discloses a perovskite precursor solution based on the addition of 1-thioglycerol and a solar cell. By adding 0.01 to 0.5 mg / mL of 1-thioglycerol to the perovskite precursor solution, the defects of elemental iodine are reduced, the deterioration of the perovskite material is inhibited, so as to extend the storage period of the perovskite precursor solution. And the perovskite thin film is prepared in the air using the precursor solution added with 1-thioglycerol, solving the dependence on the inert atmosphere for the preparation of the perovskite thin film. At the same time, the grain size of the perovskite thin film can be increased, the grain boundaries can be reduced, the stability and the optoelectronic performance can be improved, and the formation of metal Pb 0 defects can be inhibited. The solar cell prepared based on the perovskite thin film can continuously and reversibly dynamically repair the defects in the whole life cycle of device preparation and service by means of the redox shuttle system constructed by 1-thioglycerol, improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor technology, and in particular relates to a perovskite precursor solution and a solar cell based on the addition of 1-thioglycerol. Background Art

[0002] Perovskite solar cells have attracted widespread attention in recent years due to their advantages such as high photoelectric conversion efficiency, low cost and solution preparation. However, the soft lattice ion characteristics of perovskite materials make them prone to degradation in air environments, resulting in poor photoelectric performance of the prepared devices. In addition, the I⁻ ions in the perovskite precursor solution are easily oxidized in the air, leading to the generation of iodine I2 and I3⁻ ions, which in turn trigger the collapse of the perovskite lattice and the formation of defects, as well as corrosion of the metal electrode. The further generated metal Pb 0 As deep energy level defects, they can lead to non-radiative recombination of photogenerated carriers, seriously damaging the optoelectronic performance of the device.

[0003] The existing method is to use freshly prepared non-deteriorated perovskite precursor solution and spin-coat the perovskite film in a glove box filled with inert gas to prevent moisture and oxygen in the air from damaging the perovskite material, and to repair defects through post-interface treatment strategies. This will undoubtedly increase the cost and steps of device preparation, including the cost of solution deterioration, the cost of inert gas, and the cost of glove box equipment.

[0004] By adding reducing agents such as formate, vitamin C, and trap-based derivative materials to the perovskite precursor solution, the oxidation of I⁻ to I2 can be effectively inhibited. However, such reducing agents are sacrificial agents, that is, after the reducing agent material itself is oxidized by I2 or O2, it can no longer exert its ability to repair defects, and therefore cannot repair the defects that are continuously generated during the preparation and service life cycle of perovskite solar cells.

[0005] In view of this, it is of great practical significance to develop a method that can extend the shelf life of perovskite precursor solution, stably prepare perovskite solar cells in an air environment, and continuously repair defects in the device throughout its entire life cycle of preparation and service. Summary of the invention

[0006] In view of the deficiencies of the prior art, the present invention provides a perovskite precursor solution based on the addition of 1-thioglycerol and a solar cell. By introducing a trace amount of reducing agent 1-thioglycerol (1-ThL) into the perovskite precursor solution, on the one hand, the deterioration of the perovskite material can be inhibited to extend the storage period of the perovskite precursor solution, and on the other hand, the dependence on an inert atmosphere for the preparation of the perovskite thin film can be solved, so that the perovskite solar cell can be stably prepared in an air environment. In addition, the redox shuttle system constructed by 1-thioglycerol can continuously and reversibly dynamically repair the defects in the entire life cycle of device preparation and service, improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0007] A perovskite precursor solution based on the addition of 1-thioglycerol, wherein the perovskite precursor solution is a perovskite component precursor solution or a PbI2 solution and an ammonium salt solution, and the concentration of the added 1-thioglycerol is 0.01~0.5 mg / mL.

[0008] Preferably, the perovskite component is PbI2, or a combination of PbI2 and one or more of PbBr2, CsI, CsBr, and the ammonium salt is a combination of multiple of FAI, MAI, MABr, MACl.

[0009] A method for preparing a perovskite thin film based on the addition of 1-thioglycerol, which prepares a perovskite precursor solution based on the addition of 1-thioglycerol, and spin-coats the perovskite component precursor solution by a one-step method, or spin-coats the perovskite PbI2 solution and the ammonium salt solution in air successively by a two-step method.

[0010] A solar cell based on the addition of 1-thioglycerol, which is prepared in air by solution spin-coating using a perovskite precursor solution added with 1-thioglycerol.

[0011] A method for preparing a solar cell based on the addition of 1-thioglycerol, in air, an electron transport layer, a perovskite layer, a hole transport layer and a metal electrode are successively deposited on the surface of a transparent conductive substrate to obtain a formal solar cell. The perovskite layer is obtained by spin-coating a perovskite precursor solution added with 1-thioglycerol.

[0012] Preferably, a hole transport layer, a perovskite layer, an electron transport layer and a metal electrode are successively deposited on the surface of the transparent conductive substrate to obtain a reverse solar cell.

[0013] Preferably, the electron transport layer is a thin film made of a composite material of one or more of TiO2, SnO2, ZnO2, C 60 , PC 61 BM.

[0014] Preferably, the hole transport layer is Spiro-OMeTAD, PTAA or NiOx A thin film made of the material.

[0015] Preferably, the metal electrode is one of gold, silver, and copper.

[0016] The present invention has the following beneficial effects:

[0017] 1. By adding a trace amount of 1-thioglycerol to the perovskite precursor solution, the storage period of the perovskite precursor solution can be greatly extended, and the dependence on an inert atmosphere during the preparation of the perovskite thin film can also be solved, thereby reducing the input costs of the perovskite solar cell preparation in terms of perovskite precursor solution deterioration loss, inert gas consumption, and glove box equipment procurement.

[0018] 2. The additive 1-thioglycerol can not only reduce the elemental I2 defects, but its product disulfide can also oxidize the metal Pb 0 deep-level defects, thereby regulating the stoichiometric ratio balance of the perovskite component. And the disulfide can return to the 1-thioglycerol state and continue to reduce the continuously generated I2 / I3 - defects. In this way, a reversible redox shuttle system is constructed, realizing the dynamic defect repair of the entire life cycle of the perovskite solar cell preparation and service. Description of the Drawings

[0019] Figure 1 UV-visible absorption spectra of the ammonium salt solutions in Comparative Example 1 and Example 1;

[0020] Figure 2 Scanning electron microscope images of the perovskite thin films in Comparative Example 1 and Example 1;

[0021] Figure 3 X-ray diffraction patterns of the perovskite thin films in Comparative Example 1 and Example 1;

[0022] Figure 4 Steady-state fluorescence spectra of the perovskite thin films in Comparative Example 1 and Example 1;

[0023] Figure 5 Water contact angle comparison diagrams of the perovskite thin films in Comparative Example 1 and Example 1;

[0024] Figure 6 X-ray photoelectron spectroscopy diagrams of the aged perovskite thin films in Comparative Example 1 and Example 1;

[0025] Figure 7 Reaction result comparison diagrams of the metal Pb powder and I2 before and after the addition of 1-thioglycerol;

[0026] Figure 8 Current density-voltage curves of the perovskite solar cells in Comparative Example 1 and Example 1;

[0027] Figure 9 It is the graph of the stability change trend of the perovskite solar cells in Comparative Example 1 and Example 1. Specific embodiments

[0028] The present invention will be further explained and illustrated with reference to the accompanying drawings as follows;

[0029] Comparative Example 1

[0030] In this example, a perovskite precursor solution without the addition of 1-thioglycerol and a formal solar cell were prepared as a comparative example. The specific steps are as follows:

[0031] Step 1: The transparent conductive substrate was ultrasonically cleaned with deionized water, acetone, and ethanol in sequence, and after drying, the transparent conductive substrate was subjected to plasma treatment.

[0032] Step 2: A layer of SnO2 film was spin-coated on the surface of the plasma-treated transparent conductive substrate, and then annealed at 150 °C for 30 minutes to obtain an electron transport layer.

[0033] Step 3: PbI2 and CsBr were dissolved in N,N-dimethylformamide and dimethyl sulfoxide mixed in a volume ratio of 9:1. The concentration of PbI2 was 1.5 mol / L, and the concentration of CsBr was 0.04 mol / L to obtain a PbI2 precursor solution.

[0034] FAI and MACl were dissolved in isopropanol. The concentration of FAI was 90 mg / mL, and the concentration of MACl was 9 mg / mL to obtain an ammonium salt solution.

[0035] Step 4: The PbI2 precursor solution was spin-coated on the surface of the electron transport layer at a speed of 1500 revolutions per minute, and then annealed at 70 °C for 60 seconds to form a PbI2 film. Subsequently, the ammonium salt solution was spin-coated on the surface of the PbI2 film at a speed of 1800 revolutions per minute, and then annealed at 150 °C for 20 minutes to obtain a perovskite film.

[0036] Step 5: A layer of Spiro-OMeTAD film was spin-coated on the surface of the perovskite film to obtain a hole transport layer. A silver metal electrode was evaporated on the surface of the hole transport layer to obtain a formal solar cell based on the addition of 1-thioglycerol.

[0037] Example 1

[0038] In this example, a perovskite precursor solution and a formal solar cell based on the addition of 1-thioglycerol were prepared. The specific steps are as follows:

[0039] Step 1: Ultrasonically clean the transparent conductive substrate with deionized water, acetone, and ethanol in sequence. After drying, perform plasma treatment on the transparent conductive substrate.

[0040] Step 2: Spin-coat a layer of SnO2 thin film on the surface of the plasma-treated transparent conductive substrate, and then anneal at 150 °C for 30 minutes to obtain an electron transport layer.

[0041] Step 3: Dissolve PbI2, CsBr, and 1-ThL in N,N-dimethylformamide and dimethyl sulfoxide mixed in a volume ratio of 9:1. The concentration of PbI2 is 1.5 mol / L, the concentration of CsBr is 0.04 mol / L, and the concentration of 1-thioglycerol is 0.1 mg / mL to obtain a PbI2 precursor solution added with 1-thioglycerol.

[0042] Dissolve FAI, MACl, and 1-ThL in isopropanol. The concentration of FAI is 90 mg / mL, the concentration of MACl is 9 mg / mL, and the concentration of 1-thioglycerol is 0.1 mg / mL to obtain an ammonium salt solution added with 1-thioglycerol.

[0043] Measure the ultraviolet-visible absorption spectra of the ammonium salt solutions prepared in Comparative Example 1 and Example 1 at 0 days, 7 days, and 14 days of aging respectively. The results are as Figure 1 shown. It can be seen from Figure 1 that for the solution of Comparative Example 1, after standing for 14 days, a large characteristic peak appears at a wavelength of 360 nm, a large amount of I2 / I3⁻ is formed, and the solution has deteriorated. However, for Example 1 added with the reducing agent 1-ThL, there is basically no characteristic peak at a wavelength of 360 nm, that is, basically no formation of I2 / I3⁻, demonstrating the excellent ability of 1-ThL to extend the storage period of the perovskite precursor solution.

[0044] Step 4: Spin-coat the perovskite component precursor solution added with 1-thioglycerol on the surface of the electron transport layer at a speed of 1500 revolutions per minute, and then anneal at 70 °C for 60 seconds to form a PbI2 film. Subsequently, spin-coat the ammonium salt solution added with 1-thioglycerol on the surface of the PbI2 film at a speed of 1800 revolutions per minute, and then anneal at 150 °C for 20 minutes to obtain a perovskite thin film.

[0045] The comparison results of the scanning electron microscope images, X-ray diffraction patterns, and steady-state fluorescence spectra of the perovskite thin films prepared in Comparative Example 1 and Example 1 are respectively as Figure 2 、 3 、4 shown. It can be seen from Figure 2It can be seen that the particle sizes of the perovskite crystals in Comparative Example 1 mostly concentrate below 1 μm, and there are a large number of crystals smaller than 0.5 μm. For the perovskite thin film prepared from the perovskite precursor solution added with 1-thioglycerol in Example 1, the particle sizes of the perovskite crystals generally exceed 1 μm. That is, the grains of the perovskite thin film optimized with the 1-thioglycerol additive are larger and the grain boundaries are fewer. In addition, there is less unreacted PbI2 that can induce the degradation of the perovskite film in the perovskite thin film, and the perovskite defects are reduced, which helps to improve the stability. From Figure 3 It can be seen that the (110) crystal plane of the perovskite thin film at 2θ = 14.2° in Example 1 is significantly enhanced, indicating the improvement of the perovskite crystallization quality, which is beneficial to the improvement of the optoelectronic performance of the prepared perovskite solar cell. From Figure 4 It can be seen that the PL fluorescence intensity of the perovskite thin film prepared in Example 1 is significantly enhanced compared with that in Comparative Example 1, indicating that the addition of 1-thioglycerol can passivate the perovskite defects, including the inhibition of defect formation and the repair of defects, thereby reducing the non-radiative recombination.

[0046] Measure the water contact angles of the perovskite thin films prepared in Comparative Example 1 and Example 1, and the results are as Figure 5 shown. The water contact angle of the perovskite thin film prepared in Example 1 is 69°, which is higher than 59° of Comparative Example 1, indicating that the addition of 1-thioglycerol can endow the perovskite thin film with more excellent hydrophobic properties, which is helpful for the stability of the thin film during preparation in an air environment and for the device to be stored in a better humidity environment.

[0047] Age the perovskite thin films prepared in Comparative Example 1 and Example 1, and measure the X-ray photoelectron spectroscopy after aging. The results are as Figure 6 shown. Among them, a characteristic peak of metallic Pb appears in the perovskite thin film prepared in Comparative Example 1 after aging, indicating the formation of a large number of Pb 0 defects. Pb 0 defects, as deep-level defects, will cause non-radiative recombination of photo-generated carriers, greatly damaging the optoelectronic performance of the perovskite solar cell. However, no Pb 0 characteristic peak is observed in the perovskite thin film prepared in Example 1 after aging, indicating that the addition of 1-thioglycerol can inhibit the formation of metallic Pb 0 defects. 0

[0048] To further verify the effect of 1-thioglycerol on I2 and metallic Pb 0The ability to repair defects. At 50 °C, metallic Pb powder and I2 were mixed in a solution. 1-Thioglycerol was added to the experimental group, while not added to the control group. After stirring for 2 hours and standing for a period of time, no sedimentation of metallic Pb powder was observed in the experimental group, indicating that all metallic Pb had reacted with I2 to form PbI2. After 2 hours of stirring and standing, there was still a lot of Pb powder remaining at the bottom in the control group without the addition of 1-ThL, indicating that the reaction of metallic Pb was not complete. As Figure 7 shown, it was proved that 1-thioglycerol could promote the reaction of Pb with I2, and 1-thioglycerol and its reaction products could construct a redox shuttle system to achieve the repair of I2 and metallic Pb 0 defects.

[0049] Step 5: Spin-coat a layer of Spiro-OMeTAD film on the surface of the perovskite film to obtain a hole transport layer. Evaporate a silver metal electrode on the surface of the hole transport layer to obtain a formal solar cell with the addition of 1-thioglycerol.

[0050] Measure the current density-voltage curves of the solar cells prepared in Comparative Example 1 and Example 1. The results are as Figure 8 shown. The photoelectric conversion efficiency of the solar cell prepared in Example 1 = 25.34%, the open-circuit voltage = 1.175 V, the fill factor = 84.27%, and the short-circuit current = 25.59 mA cm -2 . Compared with the solar cell prepared in Comparative Example 1, it had more excellent photoelectric conversion performance, indicating that the addition of 1-thioglycerol was helpful for the preparation of perovskite films in an air environment and had the advantage of improving the photoelectric performance of the device.

[0051] At the same time, the perovskite precursor solutions prepared in Comparative Example 1 and Example 1 were aged. The perovskite layer of the solar cell was prepared using the aged perovskite precursor solution, and the current density-voltage curves of the solar cells prepared using the aged perovskite precursor solution were measured. The results are as Figure 8 shown. It can be seen that for the battery prepared with the perovskite precursor solution without the addition of 1-thioglycerol in Comparative Example 1, the efficiency decreased significantly, indicating that the deteriorated perovskite precursor solution was not suitable for continued use. For the battery prepared with the perovskite precursor solution added with 1-thioglycerol in Example 1, it was basically consistent with the current density-voltage curve before aging, proving that the addition of 1-thioglycerol had an effect of extending the storage period of the perovskite precursor solution.

[0052] Compare the stability of the solar cells prepared in Comparative Example 1 and Example 1. The results are as Figure 9As shown, after continuous illumination of the solar cell prepared in Example 1 at the maximum power point for 500 hours, the photoelectric conversion efficiency basically did not decrease, while that of Comparative Example 1 decreased significantly. This shows that the addition of 1-thioglycerol can enhance the stability of perovskite solar cells, enabling them to serve more efficiently for a longer time.

[0053] Example 2

[0054] In this example, a perovskite precursor solution and a formal solar cell based on the addition of 1-thioglycerol were prepared. The specific steps are as follows:

[0055] Step 1: Ultrasonically clean the transparent conductive substrate with deionized water, acetone, and ethanol in sequence. After drying, perform plasma treatment on the transparent conductive substrate.

[0056] Step 2: Spin-coat a layer of SnO2 film on the surface of the plasma-treated transparent conductive substrate, and then anneal it at 150 °C for 30 minutes to obtain the electron transport layer.

[0057] Step 3: Dissolve PbI2 and 1-ThL in N,N-dimethylformamide and dimethyl sulfoxide mixed in a volume ratio of 9:1. The concentration of PbI2 is 1.5 mol / L, and the concentration of 1-thioglycerol is 0.1 mg / mL to obtain a perovskite component precursor solution added with 1-thioglycerol.

[0058] Dissolve FAI, MACl, and 1-ThL in isopropyl alcohol. The concentration of FAI is 90 mg / mL, the concentration of MACl is 9 mg / mL, and the concentration of 1-thioglycerol is 0.1 mg / mL to obtain an ammonium salt solution added with 1-thioglycerol.

[0059] Step 4: Spin-coat the perovskite component precursor solution added with 1-thioglycerol on the surface of the electron transport layer at a speed of 1500 revolutions per minute, and then anneal it at 70 °C for 60 seconds to form a PbI2 film. Subsequently, spin-coat the ammonium salt solution added with 1-thioglycerol on the surface of the PbI2 film at a speed of 1800 revolutions per minute, and then anneal it at 150 °C for 20 minutes to obtain a perovskite film.

[0060] Step 5: Spin-coat a layer of Spiro-OMeTAD film on the surface of the perovskite film to obtain the hole transport layer. Evaporate a silver metal electrode on the surface of the hole transport layer to obtain a formal solar cell based on the addition of 1-thioglycerol.

[0061] Example 3

[0062] In this example, a perovskite precursor solution and a tandem solar cell based on the addition of 1-thioglycerol were prepared. The specific steps are as follows:

[0063] Step 1: Ultrasonically clean the transparent conductive substrate with deionized water, acetone, and ethanol in sequence. After drying, perform plasma treatment on the transparent conductive substrate.

[0064] Step 2: Spin-coat a layer of NiO x film on the surface of the plasma-treated transparent conductive substrate to obtain a hole transport layer.

[0065] Step 3: Dissolve PbI2 and 1-ThL in a mixture of N,N-dimethylformamide and dimethyl sulfoxide with a volume ratio of 9:1. The concentration of PbI2 is 1.5 mol / L, and the concentration of 1-thioglycerol is 0.1 mg / mL to obtain a perovskite component precursor solution added with 1-thioglycerol.

[0066] Dissolve FAI, MACl, and 1-ThL in isopropanol. The concentration of FAI is 90 mg / mL, the concentration of MACl is 9 mg / mL, and the concentration of 1-thioglycerol is 0.1 mg / mL to obtain an ammonium salt solution added with 1-thioglycerol.

[0067] Step 4: Spin-coat the perovskite component precursor solution added with 1-thioglycerol on the surface of the hole transport layer at a speed of 1500 revolutions per minute, and then anneal at 70 °C for 60 seconds to form a PbI2 film. Subsequently, spin-coat the ammonium salt solution added with 1-thioglycerol on the surface of the PbI2 film at a speed of 1800 revolutions per minute, and then anneal at 150 °C for 20 minutes to obtain a perovskite film.

[0068] Step 5: Spin-coat a layer of SnO2 film on the surface of the perovskite film, and then anneal at 150 °C for 30 minutes to obtain an electron transport layer. Evaporate a silver metal electrode on the surface of the electron transport layer to obtain a reverse solar cell based on the addition of 1-thioglycerol.

[0069] Example 4

[0070] This example prepares a perovskite precursor solution and a reverse solar cell based on the addition of 1-thioglycerol. On the basis of Example 3, use C 60 and PC 61 BM mixed material to prepare the electron transport layer.

[0071] Example 5

[0072] This example prepares a perovskite precursor solution and a reverse solar cell based on the addition of 1-thioglycerol. On the basis of Example 3, dissolve PbI2 with PbBr2, CsI, CsBr, and FAI in a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide, and add 1-thioglycerol to prepare a perovskite component precursor solution added with 1-thioglycerol.

Claims

1. A perovskite precursor solution based on the addition of 1-thioglycerol, the perovskite precursor solution being a PbI2 solution and an ammonium salt solution, characterized in that: The PbI2 solution and the ammonium salt solution each contain 1-thioglycerol at a concentration of 0.01 to 0.5 mg / mL.

2. The perovskite precursor solution based on the addition of 1-thioglycerol according to claim 1, wherein: The concentration of the 1-thioglycerol is 0.1 mg / mL.

3. The perovskite precursor solution based on the addition of 1-thioglycerol as claimed in claim 1, wherein: The ammonium salt is a combination of multiple ones among FAI, MAI, MABr, and MACl.

4. Preparation method of perovskite thin film based on the addition of 1-thioglycerol, characterized in that: To prepare the perovskite precursor solution with the addition of 1-thioglycerol as described in any one of Claims 1 to 3, the perovskite PbI2 solution and the ammonium salt solution are successively spin-coated in air by a two-step method to prepare a perovskite film.

5. A solar cell based on the addition of 1-thioglycerol, characterized in that: The perovskite film of the solar cell is prepared by the method as described in Claim 4.

6. Preparation method of solar cell based on addition of 1-thioglycerol. In air, an electron transport layer, a perovskite layer, a hole transport layer and a metal electrode are sequentially deposited on the surface of a transparent conductive substrate to obtain a formal solar cell, characterized in that: The perovskite layer is prepared by the method as described in Claim 4.

7. The preparation method of the solar cell based on the addition of 1-thioglycerol according to claim 6, wherein: A hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode are successively deposited on the surface of a transparent conductive substrate to obtain a reverse solar cell.

8. The preparation method of the solar cell based on the addition of 1-thioglycerol as claimed in claim 6, wherein: The electron transport layer is a thin film made of one or more composite materials of TiO2, SnO2, ZnO2, C 60 , PC 61 BM 9. The preparation method of the solar cell based on the addition of 1-thioglycerol according to claim 6, characterized in that: The hole transport layer is a thin film made of Spiro-OMeTAD, PTAA or NiO x material.

10. The preparation method of the solar cell based on the addition of 1-thioglycerol according to claim 6, wherein: The metal electrode is one of gold, silver, and copper.

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