Flexible perovskite solar cell and method of manufacturing the same

Abstract

This invention discloses a flexible perovskite solar cell and its fabrication method. The fabrication of the electron transport layer of the flexible perovskite solar cell includes: depositing a SnO2 layer on a substrate using atomic layer deposition (ALD); spin-coating a SnO2 dispersion doped with glycine hydrochloride onto the resulting SnO2 deposited layer to form a SnO2 spin-coating layer, thus obtaining a double SnO2 layer structure containing both the SnO2 deposited layer and the SnO2 spin-coating layer; and annealing the structure at 80-100°C to obtain the electron transport layer of the flexible perovskite solar cell. This electron transport layer has a dense and uniform structure, can be fabricated at low temperatures, is corrosion-resistant, and promotes the crystallization of the perovskite layer.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and particularly to the field of flexible perovskite solar cells. Background Technology

[0002] Perovskite solar cells (PSCs) are the most promising new type of solar cell in recent years, with the fastest improvement in photoelectric conversion efficiency (PCE). The PCE of their single-junction cells has climbed to 26.9%. At the same time, PSCs also have the advantages of low cost and flexibility, showing great development potential in the field of flexible photovoltaics.

[0003] However, the existing fabrication process of flexible perovskite solar cells still has many problems. The key problem is that the electron transport layer prepared by spin coating and chemical bath deposition is not dense enough and the solution will corrode the substrate, resulting in a significant decrease in the fill factor and open circuit voltage of the cell. In addition, the above methods require high-temperature post-treatment, which is contrary to the high-temperature resistance of flexible substrates, which obviously limits the further application of flexible PSCs. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a novel flexible perovskite solar cell and its fabrication method. The flexible perovskite solar cell possesses a dense, uniform, and smooth corrosion-resistant electron transport layer, can be fabricated at low temperatures, and promotes the crystallization of the perovskite layer.

[0005] The technical solution of the present invention is as follows:

[0006] A method for fabricating flexible perovskite solar cells, comprising:

[0007] A substrate for depositing the electron transport layer of a flexible perovskite solar cell was obtained.

[0008] An electron transport layer for a flexible perovskite solar cell is fabricated on the substrate;

[0009] A perovskite layer is fabricated on the electron transport layer of the flexible perovskite solar cell;

[0010] A n-butylammonium iodide passivation layer is prepared on the perovskite layer;

[0011] A hole transport layer is prepared on the n-butylammonium iodide passivation layer;

[0012] A metal electrode is fabricated on the hole transport layer;

[0013] The fabrication of the electron transport layer of the flexible perovskite solar cell includes:

[0014] (1) A SnO2 layer was deposited on the substrate by atomic layer deposition to obtain a SnO2 deposition layer;

[0015] (2) A SnO2 dispersion doped with glycine hydrochloride is spin-coated onto the SnO2 deposited layer to form a SnO2 spin-coating layer. The resulting double SnO2 layer structure containing the SnO2 deposited layer and the SnO2 spin-coating layer is subjected to a first annealing treatment in air at a temperature of 80-100℃ to obtain the electron transport layer of the flexible perovskite solar cell.

[0016] The method for obtaining the SnO2 dispersion doped with glycine hydrochloride includes:

[0017] An aqueous dispersion of SnO2 was added to a deionized aqueous solution of glycine hydrochloride and mixed thoroughly to obtain the SnO2 dispersion of the doped glycine hydrochloride.

[0018] The electron transport layer of the present invention contains a SnO2 layer deposited by the ALD method, which has a dense structure and can protect the flexible substrate from SnO2 solution corrosion.

[0019] According to some preferred embodiments of the present invention, the thickness of the SnO2 deposition layer is 18-50 nm, more preferably 30 nm.

[0020] According to some preferred embodiments of the present invention, the thickness of the SnO2 spin coating is 20-30 nm, more preferably 25-35 nm.

[0021] According to some preferred embodiments of the present invention, the concentration of SnO2 in the aqueous dispersion of SnO2 is 10-20 wt%.

[0022] According to some preferred embodiments of the present invention, the volume ratio of the deionized aqueous solution of glycine hydrochloride to the aqueous dispersion of SnO2 is 4-6:1.

[0023] According to some preferred embodiments of the present invention, the atomic layer deposition method includes: at a pressure of 2 × 10⁻⁶ -4 Pa-4×10 -4 Under the conditions of Pa, carrier gas flow rate of 20-40 sccm, and temperature of 80-100℃, the following steps were performed: (a) pulse injection of ultrapure water for 0.01-0.02s, followed by a 3-5s wait; (b) pulse injection of tetra(dimethylamino)tin (TDMASn) source for 0.05-0.15s, followed by a 3-5s wait; then the process (a)-(b) was repeated 200-300 times, followed by natural cooling to 55-65℃.

[0024] According to some preferred embodiments of the present invention, the spin coating includes: spin coating the SnO2 dispersion doped with glycine hydrochloride onto the SnO2 deposition layer at a rotation speed of 4000-5000 rpm and an acceleration rate of 1000-2500 rpm / s.

[0025] According to some preferred embodiments of the present invention, in the atomic layer deposition method, the water-to-oxygen ratio of the deposited material is 0.02-0.03.

[0026] According to some preferred embodiments of the present invention, in the atomic layer deposition method, processes (a)-(b) are repeated 250 times.

[0027] According to some preferred embodiments of the present invention, the substrate is selected from polyethylene terephthalate coated indium tin oxide conductive material (PEN / ITO).

[0028] According to some preferred embodiments of the present invention, the preparation method includes:

[0029] (1) A pretreated substrate was obtained by irradiating a polyethylene terephthalate-coated indium tin oxide conductive material substrate with ultraviolet light.

[0030] (2) The flexible perovskite solar electron transport layer is obtained on the pretreated substrate to obtain a substrate containing the electron transport layer;

[0031] (3) Formamidin hydroiodide (FAI), methylamine chloride (MACl), and lead iodide (PbI2) are dissolved in a mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) to form a perovskite precursor solution. This solution is then spin-coated onto the substrate containing the electron transport layer. Chlorobenzene is added dropwise during the spin-coating process. After spin-coating is completed, a second annealing treatment is performed to obtain the substrate containing the perovskite layer.

[0032] (4) Dissolve the passivating agent n-butylammonium iodide (BAI) in isopropanol to obtain a passivation precursor solution, spin-coat it onto the substrate of the perovskite layer, and perform a third annealing treatment after spin-coating to obtain a substrate containing a passivation layer.

[0033] (5) Dissolve 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) in chlorobenzene, then add an acetonitrile solution of 4-tert-butylpyridine (tBP) and lithium bis(trifluoromethane)sulfonylimide (Li-TFSI) to obtain a hole precursor solution, spin-coat it onto the substrate containing the passivation layer, and dry it after spin-coating to obtain a substrate containing a hole transport layer;

[0034] (6) Silver is deposited as a metal electrode on the substrate containing the hole transport layer by thermal evaporation to obtain a flexible perovskite solar cell.

[0035] According to some preferred embodiments of the present invention, the pretreatment further includes cutting the polyethylene terephthalate coated indium tin oxide conductive material into a size of 1.5cm × 1.5cm.

[0036] According to some preferred embodiments of the present invention, the volume ratio of N,N-dimethylformamide and dimethyl sulfoxide is 1:4, the concentration of methylamine chloride is 0.1-1.0 mol / ml, the concentration of formamidinium hydroiodate is 1.0-2.0 mol / ml, and the concentration of lead iodide is 1.0-2.0 mol / ml.

[0037] According to some preferred embodiments of the present invention, the concentration of n-butylammonium iodide in the passivation precursor solution is 0.5-5 mg / mL, more preferably 2 mg / mL.

[0038] According to some preferred embodiments of the present invention, the deposition rate of the deposited silver is Its thickness is 50-200nm, more preferably 100nm.

[0039] According to some preferred embodiments of the present invention, the temperature of the second annealing treatment is 80-100°C and the time is 10-40 min.

[0040] According to some preferred embodiments of the present invention, the temperature of the third annealing treatment is 70-90°C and the time is 1-10 min.

[0041] According to the preferred embodiments described above, the temperature of the entire fabrication process of the flexible perovskite solar cell of the present invention can be controlled within 100°C, thus avoiding bending of the flexible substrate at high temperatures.

[0042] According to some preferred embodiments of the present invention, the spin coating speed in step (3) is 4400-4600 rpm, the speed increase is 1400-1600 rpm / s, the spin coating time is 20-30s, and chlorobenzene is added dropwise at 15-19s.

[0043] According to some preferred embodiments of the present invention, the spin coating speed in step (4) is 4900-5100 rpm, the speed increase is 1900-2100 rpm / s, and the spin coating time is 25-35s.

[0044] According to some preferred embodiments of the present invention, the spin coating speed in step (5) is 3900-4100 rpm, the acceleration speed is 900-1100 rpm / s, and the spin coating time is 25-35s.

[0045] According to some preferred embodiments of the present invention, the thickness of the deposited silver is 100 nm, and the deposition rate is 0-5 nm. The deposition rate of 5-10nm is The deposition rate for 10-20nm is The deposition rate for 20-50nm is The deposition rate for 50-100nm is

[0046] According to some specific embodiments of the present invention, the flexible perovskite solar cell obtained by the present invention operates at room temperature and 100 mW / cm². 2 Under simulated solar illumination, an open-circuit photovoltage of 1.14V and an open-circuit photovoltage of 24.75mA / cm² can be obtained. 2 It has a short-circuit photocurrent and a photoelectric conversion efficiency of 23.51%. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of the flexible perovskite solar cell obtained in Example 1.

[0048] Figure 2 The image shows an atomic force microscope comparison of the ALD SnO2 substrate obtained in Example 1 and the SnO2 substrates of Comparative Examples 1-3.

[0049] Figure 3 The images show a comparison of scanning electron microscope (SEM) images of the ALD SnO2 substrate obtained in Example 1 and the SnO2 substrates of Comparative Examples 1-3.

[0050] Figure 4 The images show an atomic force microscope comparison of the ALD SnO2 substrate obtained in Example 1 and the SnO2 substrates of Comparative Examples 1-3 after spin-coating with perovskite layers.

[0051] Figure 5 The image shows a comparison of X-ray diffraction patterns of the perovskite solar cells obtained in Example 1 and Comparative Examples 1 and 3.

[0052] Figure 6 Box plots showing the power conversion efficiency (PCE), current density (Jsc), switching voltage (Voc), and fill factor (FF) of the perovskite solar cells obtained in Example 1 and Comparative Examples 1-3.

[0053] Figure 7 The graph shows the test results of the power conversion efficiency (PCE), current density (Jsc), turn-on voltage (Voc), and fill factor (FF) of the perovskite solar cell obtained in Example 1. Detailed Implementation

[0054] The present invention will now be described in detail with reference to embodiments and accompanying drawings. However, it should be understood that the embodiments and drawings are for illustrative purposes only and do not constitute any limitation on the scope of protection of the present invention. All reasonable modifications and combinations included within the inventive spirit of the present invention fall within the scope of protection of the present invention.

[0055] Example 1

[0056] Flexible perovskite solar cells are fabricated using the following steps:

[0057] (1) Pretreatment of the substrate: Cut the PEN / ITO substrate to 1.5×1.5cm, remove the protective film on the surface, and then clean it with a UV ozone cleaner for 30 minutes to obtain the pretreated substrate.

[0058] (2) Fabrication of the electron transport layer, including:

[0059] SnO2 layer was prepared using the ALD method: The sample chamber was inflated to a pressure reading of 760 torr, the chamber cover was opened and the pretreated substrate was placed in. The carrier gas flow rate was set to 30 sccm (1 sccm = 1 mL / min), the chamber temperature was set to 100℃, and after the temperature stabilized for 120s, ultrapure water was pulsed in for 0.015s. After waiting for 4s, TDMASn source pulse was pulsed in for 0.1s, and after waiting for 4s, the process of ultrapure water pulse to TDMASn source pulse was repeated 250 times to complete the deposition. After the deposition was completed, the temperature was allowed to drop back to 60℃, the chamber was inflated and a sample was taken to obtain a substrate containing an anti-corrosion SnO2 film.

[0060] Prepare a 4 mg / mL deionized aqueous solution of glycine hydrochloride with a purity of 99.8%. Take 212 μL of the obtained glycine hydrochloride solution and mix it with 788 μL of deionized water. Then, slowly add 200 μL of a 15% aqueous dispersion of SnO2 and stir until homogeneous to obtain a dispersion. Spin-coat the dispersion onto a substrate containing an anti-corrosion SnO2 film at a speed of 5000 rpm and an intensification rate of 2000 rpm / s to obtain a substrate containing a double layer of SnO2. Place the substrate on a constant temperature heating table and anneal it in air for 60 minutes at an annealing temperature of 100℃ to obtain a substrate containing an electron transport layer, namely ITO(PEN) / SnO2.

[0061] (3) Preparation of the perovskite layer, including:

[0062] 1.4 mol FAI, 0.42 mol MACl, and 1.53 mol PbI2 were dissolved in 800 μL DMF and 200 μL DMSO to form a perovskite precursor solution. The prepared ITO(PEN) / SnO2 was then cleaned for 5 minutes using a plasma cleaner. After cleaning, the solution was transferred to a nitrogen glove box. The well-stirred perovskite precursor solution was spin-coated onto the cleaned substrate containing the electron transport layer at a speed of 4500 rpm and an intensification rate of 1500 rpm / s for 25 seconds. At the 17th second of spin-coating, 150 μL of chlorobenzene was added as an anti-solvent. After spin-coating, the substrate was transferred to a constant temperature hot plate and annealed for 30 minutes at 100℃ to obtain the substrate containing the perovskite layer, namely ITO(PEN) / SnO2 / FAPbI3.

[0063] (4) Preparation of the BAI passivation layer, including:

[0064] 2 mg BAI was dissolved in 1 ml isopropanol and stirred until homogeneous. The resulting solution was then spin-coated onto ITO(PEN) / SnO2 / FAPbI3 at a speed of 5000 rpm and an intensification rate of 2000 rpm / s for 30 s. Subsequently, it was annealed in a nitrogen atmosphere for 5 minutes at a temperature of 80 °C to obtain a substrate containing a BAI passivation layer, namely ITO(PEN).

[0065] / SnO2 / FAPbI3 / BAI;

[0066] (5) Fabrication of the hole transport layer, including:

[0067] 72.3 mg Spiro-OMeTAD was dissolved in 1 mL of chlorobenzene, and 28.8 μL of tBP and 17.5 μL of Li-TFSI (520 mg Li-TFSI was dissolved in 1 mL of acetonitrile) were added to obtain a Spiro-OMeTAD precursor solution. The precursor solution was spin-coated on ITO(PEN) / SnO2 / FAPbI3 / BAI at a speed of 4000 rpm and an acceleration rate of 1000 rpm / s for 30 s. After spin-coating, the substrate was transferred to a drying cabinet and stored for 24 hours to obtain a substrate containing a hole transport layer.

[0068] (6) Preparation of metal electrodes, including:

[0069] A 100 nm silver electrode was deposited as a metal electrode on a substrate containing a hole transport layer using a thermal evaporation method, wherein the deposition rate for 0–5 nm was [missing information]. The deposition rate of 5-10 nm is The deposition rate of 10–20 nm is The deposition rate for 20–50 nm is The deposition rate for 50–100 nm is A flexible perovskite solar cell was obtained, the structure of which is shown in the attached figure. Figure 1 As shown.

[0070] Comparative Example 1

[0071] Comparative perovskite solar cells were prepared using the following steps:

[0072] (1) Pretreatment of the substrate: Cut the PEN / ITO substrate to 1.5×1.5cm, remove the protective film on the surface, and then clean it with a UV ozone cleaner for 30 minutes to obtain the pretreated substrate.

[0073] (2) Fabrication of the electron transport layer, including:

[0074] A 15% aqueous dispersion of SnO2 was mixed with H2O at a volume ratio of 1:5. After stirring evenly, the mixture was spin-coated onto a pretreated substrate at a speed of 5000 rpm and an acceleration rate of 2000 rpm / s. The spin-coated substrate was then placed on a constant temperature heating table and annealed in air for 60 minutes at a temperature of 100°C to obtain a substrate containing an electron transport layer.

[0075] (3) Preparation of the perovskite layer, including:

[0076] 1.4 mol FAI, 0.42 mol MACl and 1.53 mol PbI2 were dissolved in 800 μL DMF and 200 μL DMSO to form a perovskite precursor solution. The prepared substrate containing the electron transport layer was then cleaned for 5 minutes using a plasma cleaner. After cleaning, the substrate and solution were transferred to a nitrogen glove box. The well-stirred perovskite precursor solution was spin-coated onto the cleaned substrate containing the electron transport layer at a speed of 4500 rpm and an intensification rate of 1500 rpm / s for 25 seconds. At the 17th second of spin-coating, 150 μL of chlorobenzene was added dropwise as an anti-solvent. After spin-coating, the substrate was transferred to a constant temperature hot plate and annealed for 30 minutes at a temperature of 100℃ to obtain the substrate containing the perovskite layer.

[0077] (4) Preparation of the BAI passivation layer, including:

[0078] Dissolve 2 mg BAI in 1 ml isopropanol, stir well, and spin coat the resulting solution onto a substrate containing a perovskite layer for 30 s at a speed of 5000 rpm and an acceleration rate of 2000 rpm / s. Then anneal in a nitrogen atmosphere for 5 minutes at an annealing temperature of 80 °C to obtain a substrate containing a BAI passivation layer.

[0079] (5) Fabrication of the hole transport layer, including:

[0080] 72.3 mg Spiro-OMeTAD was dissolved in 1 mL of chlorobenzene, and 28.8 μL of tBP and 17.5 μL of Li-TFSI (520 mg Li-TFSI was dissolved in 1 mL of acetonitrile) were added to obtain a Spiro-OMeTAD precursor solution. This precursor solution was spin-coated on a substrate containing a BAI passivation layer at a speed of 4000 rpm and an acceleration rate of 1000 rpm / s for 30 s. After spin-coating, the substrate was transferred to a drying cabinet and stored for 24 hours to obtain a substrate containing a hole transport layer.

[0081] (6) Preparation of metal electrodes, including:

[0082] A 100 nm silver electrode was deposited as a metal electrode on a substrate containing a hole transport layer using a thermal evaporation method, wherein the deposition rate for 0–5 nm was [missing information]. The deposition rate of 5-10 nm is The deposition rate of 10–20 nm is The deposition rate for 20–50 nm is The deposition rate for 50–100 nm is A comparative perovskite solar cell was obtained.

[0083] Comparative Example 2

[0084] Comparative perovskite solar cells were prepared using the following steps:

[0085] (1) Pretreatment of the substrate: Cut the PEN / ITO substrate to 1.5×1.5cm, remove the protective film on the surface, and then clean it with a UV ozone cleaner for 30 minutes to obtain the pretreated substrate.

[0086] (2) Fabrication of the electron transport layer, including:

[0087] SnO2 layer was prepared using ALD method: The sample chamber was filled with gas until the pressure reading reached 760 torr, then the chamber cover was opened and the pretreated substrate was placed in. The carrier gas flow rate was set to 30 sccm (1 sccm = 1 mL / min), and the chamber temperature was set to 100℃. After the temperature stabilized for 120s, ultrapure water was pulsed in for 0.015s, then waited for 4s before TDMASn source pulsed in for 0.1s, waited for 4s, and then the process of ultrapure water pulse to TDMASn source pulse was repeated 150 times to complete the deposition. After the deposition was completed, the temperature was allowed to drop back to 60℃, then the chamber was filled with gas and a sample was taken to obtain a substrate containing an 18nm corrosion-resistant SnO2 film.

[0088] A 15% aqueous dispersion of SnO2 was mixed with H2O at a volume ratio of 1:5 and stirred until homogeneous to obtain a dispersion. The dispersion was then spin-coated onto a substrate containing an anti-corrosion SnO2 film at a rotation speed of 5000 rpm and an acceleration rate of 2000 rpm / s to obtain a substrate containing a double layer of SnO2. The substrate was then placed on a constant temperature heating table and annealed in air for 60 minutes at a temperature of 100°C to obtain a substrate containing an electron transport layer.

[0089] (3) Preparation of the perovskite layer, including:

[0090] 1.4 mol FAI, 0.42 mol MACl and 1.53 mol PbI2 were dissolved in 800 μL DMF and 200 μL DMSO to form a perovskite precursor solution. The prepared substrate containing the electron transport layer was then cleaned for 5 minutes using a plasma cleaner. After cleaning, the substrate and solution were transferred to a nitrogen glove box. The well-stirred perovskite precursor solution was spin-coated onto the cleaned substrate containing the electron transport layer at a speed of 4500 rpm and an intensification rate of 1500 rpm / s for 25 seconds. At the 17th second of spin-coating, 150 μL of chlorobenzene was added dropwise as an anti-solvent. After spin-coating, the substrate was transferred to a constant temperature hot plate and annealed for 30 minutes at a temperature of 100℃ to obtain the substrate containing the perovskite layer.

[0091] (4) Preparation of the BAI passivation layer, including:

[0092] Dissolve 2 mg BAI in 1 ml isopropanol, stir well, and spin coat the resulting solution onto a substrate containing a perovskite layer for 30 s at a speed of 5000 rpm and an acceleration rate of 2000 rpm / s. Then anneal in a nitrogen atmosphere for 5 minutes at an annealing temperature of 80 °C to obtain a substrate containing a BAI passivation layer.

[0093] (5) Fabrication of the hole transport layer, including:

[0094] 72.3 mg Spiro-OMeTAD was dissolved in 1 mL of chlorobenzene, and 28.8 μL of tBP and 17.5 μL of Li-TFSI (520 mg Li-TFSI was dissolved in 1 mL of acetonitrile) were added to obtain a Spiro-OMeTAD precursor solution. This precursor solution was spin-coated on a substrate containing a BAI passivation layer at a speed of 4000 rpm and an acceleration rate of 1000 rpm / s for 30 s. After spin-coating, the substrate was transferred to a drying cabinet and stored for 24 hours to obtain a substrate containing a hole transport layer.

[0095] (6) Preparation of metal electrodes, including:

[0096] A 100 nm silver electrode was deposited as a metal electrode on a substrate containing a hole transport layer using a thermal evaporation method, wherein the deposition rate for 0–5 nm was [missing information]. The deposition rate of 5-10 nm is The deposition rate of 10–20 nm is The deposition rate for 20–50 nm is The deposition rate for 50–100 nm is A comparative perovskite solar cell was obtained.

[0097] Comparative Example 3

[0098] Comparative perovskite solar cells were prepared using the following steps:

[0099] (1) Pretreatment of the substrate: Cut the PEN / ITO substrate to 1.5×1.5cm, remove the protective film on the surface, and then clean it with a UV ozone cleaner for 30 minutes to obtain the pretreated substrate.

[0100] (2) Fabrication of the electron transport layer, including:

[0101] SnO2 layer was prepared using ALD method: The sample chamber was filled with gas until the pressure reading reached 760 torr, then the chamber cover was opened and the pretreated substrate was placed in. The carrier gas flow rate was set to 30 sccm (1 sccm = 1 mL / min), and the chamber temperature was set to 100℃. After the temperature stabilized for 120 s, ultrapure water was pulsed in for 0.015 s, then waited for 4 s before TDMASn source pulsed in for 0.1 s, waited for 4 s, and then the process of ultrapure water pulse to TDMASn source pulse was repeated 250 times to complete the deposition. After the deposition was completed, the temperature was allowed to drop back to 60℃, then the chamber was filled with gas and a sample was taken to obtain a substrate containing a 30 nm corrosion-resistant SnO2 film.

[0102] A 15% aqueous dispersion of SnO2 was mixed with H2O at a volume ratio of 1:5 and stirred until homogeneous to obtain a dispersion. The dispersion was then spin-coated onto a substrate containing an anti-corrosion SnO2 film at a rotation speed of 5000 rpm and an acceleration rate of 2000 rpm / s to obtain a substrate containing a double layer of SnO2. The substrate was then placed on a constant temperature heating table and annealed in air for 60 minutes at a temperature of 100°C to obtain a substrate containing an electron transport layer.

[0103] (3) Preparation of the perovskite layer, including:

[0104] 1.4 mol FAI, 0.42 mol MACl and 1.53 mol PbI2 were dissolved in 800 μL DMF and 200 μL DMSO to form a perovskite precursor solution. The prepared substrate containing the electron transport layer was then cleaned for 5 minutes using a plasma cleaner. After cleaning, the substrate and solution were transferred to a nitrogen glove box. The well-stirred perovskite precursor solution was spin-coated onto the cleaned substrate containing the electron transport layer at a speed of 4500 rpm and an intensification rate of 1500 rpm / s for 25 seconds. At the 17th second of spin-coating, 150 μL of chlorobenzene was added dropwise as an anti-solvent. After spin-coating, the substrate was transferred to a constant temperature hot plate and annealed for 30 minutes at a temperature of 100℃ to obtain the substrate containing the perovskite layer.

[0105] (4) Preparation of the BAI passivation layer, including:

[0106] Dissolve 2 mg BAI in 1 ml isopropanol, stir well, and spin coat the resulting solution onto a substrate containing a perovskite layer for 30 s at a speed of 5000 rpm and an acceleration rate of 2000 rpm / s. Then anneal in a nitrogen atmosphere for 5 minutes at an annealing temperature of 80 °C to obtain a substrate containing a BAI passivation layer.

[0107] (5) Fabrication of the hole transport layer, including:

[0108] 72.3 mg Spiro-OMeTAD was dissolved in 1 mL of chlorobenzene, and 28.8 μL of tBP and 17.5 μL of Li-TFSI (520 mg Li-TFSI dissolved in 1 mL of acetonitrile) were added to obtain a Spiro-OMeTAD precursor solution. 35 μL of this precursor solution was transferred onto a substrate containing a BAI passivation layer and spin-coated at 4000 rpm and 1000 rpm / s for 30 s. After spin-coating, the substrate was transferred to a drying cabinet and stored for 24 hours to obtain a substrate containing a hole transport layer.

[0109] (6) Preparation of metal electrodes, including:

[0110] A 100 nm silver electrode was deposited as a metal electrode on a substrate containing a hole transport layer using a thermal evaporation method, wherein the deposition rate for 0–5 nm was [missing information]. The deposition rate of 5-10 nm is The deposition rate of 10–20 nm is The deposition rate for 20–50 nm is The deposition rate for 50–100 nm is A comparative perovskite solar cell was obtained.

[0111] Comparative Example 4

[0112] Comparative perovskite solar cells were prepared using the following steps:

[0113] (1) Pretreatment of the substrate: Cut the PEN / ITO substrate to 1.5×1.5cm, remove the protective film on the surface, and then clean it with a UV ozone cleaner for 30 minutes to obtain the pretreated substrate.

[0114] (2) Fabrication of the electron transport layer, including:

[0115] SnO2 layer was prepared using ALD method: The sample chamber was filled with gas until the pressure reading reached 760 torr, then the chamber cover was opened and the pretreated substrate was placed in. The carrier gas flow rate was set to 30 sccm (1 sccm = 1 mL / min), and the chamber temperature was set to 100℃. After the temperature stabilized for 120s, ultrapure water was pulsed in for 0.015s, then waited for 4s before TDMASn source pulsed in for 0.1s, waited for 4s, and then the process of ultrapure water pulse to TDMASn source pulse was repeated 417 times to complete the deposition. After the deposition was completed, the temperature was allowed to drop back to 60℃, then the chamber was filled with gas and a sample was taken to obtain a substrate containing a 50nm corrosion-resistant SnO2 film.

[0116] A 15% aqueous dispersion of SnO2 was mixed with H2O at a volume ratio of 1:5 and stirred until homogeneous to obtain a dispersion. The dispersion was then spin-coated onto a substrate containing an anti-corrosion SnO2 film at a rotation speed of 5000 rpm and an acceleration rate of 2000 rpm / s to obtain a substrate containing a double layer of SnO2. The substrate was then placed on a constant temperature heating table and annealed in air for 60 minutes at a temperature of 100°C to obtain a substrate containing an electron transport layer.

[0117] (3) Preparation of the perovskite layer, including:

[0118] 1.4 mol FAI, 0.42 mol MACl and 1.53 mol PbI2 were dissolved in 800 μL DMF and 200 μL DMSO to form a perovskite precursor solution. The prepared substrate containing the electron transport layer was then cleaned for 5 minutes using a plasma cleaner. After cleaning, the substrate and solution were transferred to a nitrogen glove box. The well-stirred perovskite precursor solution was spin-coated onto the cleaned substrate containing the electron transport layer at a speed of 4500 rpm and an intensification rate of 1500 rpm / s for 25 seconds. At the 17th second of spin-coating, 150 μL of chlorobenzene was added dropwise as an anti-solvent. After spin-coating, the substrate was transferred to a constant temperature hot plate and annealed for 30 minutes at a temperature of 100℃ to obtain the substrate containing the perovskite layer.

[0119] (4) Preparation of the BAI passivation layer, including:

[0120] Dissolve 2 mg BAI in 1 ml isopropanol, stir well, and spin coat the resulting solution onto a substrate containing a perovskite layer for 30 s at a speed of 5000 rpm and an acceleration rate of 2000 rpm / s. Then anneal in a nitrogen atmosphere for 5 minutes at an annealing temperature of 80 °C to obtain a substrate containing a BAI passivation layer.

[0121] (5) Fabrication of the hole transport layer, including:

[0122] 72.3 mg Spiro-OMeTAD was dissolved in 1 mL of chlorobenzene, and 28.8 μL of tBP and 17.5 μL of Li-TFSI (520 mg Li-TFSI dissolved in 1 mL of acetonitrile) were added to obtain a Spiro-OMeTAD precursor solution. 35 μL of this precursor solution was transferred onto a substrate containing a BAI passivation layer and spin-coated at 4000 rpm and 1000 rpm / s for 30 s. After spin-coating, the substrate was transferred to a drying cabinet and stored for 24 hours to obtain a substrate containing a hole transport layer.

[0123] (6) Preparation of metal electrodes, including:

[0124] A 100 nm silver electrode was deposited as a metal electrode on a substrate containing a hole transport layer using a thermal evaporation method, wherein the deposition rate for 0–5 nm was [missing information]. The deposition rate of 5-10 nm is The deposition rate of 10–20 nm is The deposition rate for 20–50 nm is The deposition rate for 50–100 nm is A comparative perovskite solar cell was obtained.

[0125] The microstructure of the substrates containing the corrosion-resistant SnO2 thin film obtained in Example 1 and Comparative Examples 1-3 was characterized, and the results are shown in the attached figure. Figure 2 AFM contrast images and appendices Figure 3 The SEM comparison images shown are attached. Figure 2 It can be seen that the surface roughness of the substrates containing the anti-corrosion SnO2 film in Example 1 and Comparative Examples 1-3 are 1.7 nm, 3.4 nm, 3.1 nm, and 1.8 nm, respectively. After SnO2 was grown in ALD, the surface roughness of the samples remained essentially unchanged, indicating that the SnO2 was grown conformally on ITO (PEN). After further spin-coating of SnO2 nanoparticles, the surface roughness decreased, indicating that the spin-coated SnO2 filled the surface depressions. According to the attached... Figure 3It can be seen that the sample directly spin-coated with SnO2 (Comparative Example 1) has a large number of defects and cracks, while the device that first obtains ALD SnO2 and then spin-coates SnO2 has good crystallization, dense grains, good flatness, and uniform grain size. Among them, the crystallization effect is the best when the thickness of ALD SnO2 is 30nm.

[0126] The results of spin-coating perovskite layers onto the ALD SnO2 substrate obtained in Example 1 and the SnO2 substrates of Comparative Examples 1-3 were observed using atomic force microscopy, and are shown in the attached figure. Figure 4 As shown, it can be seen that after using ALD, more nanoscale pores appeared in the film and the film roughness was low (the roughness value was 33.846 nm, which was significantly lower than the 44.199 nm of the control group).

[0127] Furthermore, the perovskite solar cells obtained in Example 1 and Comparative Examples 1 and 3 were characterized by X-ray diffraction, and the results are shown in the appendix. Figure 5 As shown, the perovskite film prepared on the SnO2 electron transport layer exhibits a simple FAPbI3 phase, with two strongest diffraction peaks at 14.04° and 28.02°, corresponding to the (100) and (200) crystal planes of the perovskite crystal. The broad diffraction peak at approximately 26.8° is a typical feature of the polymer PEN substrate. The results indicate that the perovskite film prepared in Example 1 has the strongest diffraction peaks and the best perovskite crystallization effect.

[0128] Furthermore, the power conversion efficiency, current density (Jsc), turn-on voltage (Voc), and fill factor (FF) of the perovskite solar cells obtained in Example 1 and Comparative Examples 1-3 were compared and tested. The results are shown in the appendix. Figure 6 As shown, the test results of Example 1 are attached. Figure 7 As shown. (Through) Figure 6 , 7 It can be seen that the photoelectric performance of the perovskite solar cell of the present invention is significantly better than that of conventional devices, at room temperature and 100mW / cm². 2 Under simulated solar illumination, the perovskite solar cell of Example 1 exhibited an open-circuit photovoltage of 1.14V and a short-circuit photocurrent of 24.75mA / cm². 2 The photoelectric conversion efficiency is 23.51%.

[0129] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for fabricating flexible perovskite solar cells, characterized in that, It includes: A substrate for depositing the electron transport layer of a flexible perovskite solar cell was obtained. An electron transport layer for a flexible perovskite solar cell is fabricated on the substrate; A perovskite layer is fabricated on the electron transport layer of the flexible perovskite solar cell; A n-butylammonium iodide passivation layer is prepared on the perovskite layer; A hole transport layer is prepared on the n-butylammonium iodide passivation layer; A metal electrode is fabricated on the hole transport layer; The fabrication of the electron transport layer of the flexible perovskite solar cell includes: (1) A SnO2 layer was deposited on the substrate by atomic layer deposition to obtain a SnO2 deposition layer; (2) A SnO2 dispersion doped with glycine hydrochloride is spin-coated onto the SnO2 deposited layer to form a SnO2 spin-coating layer. The resulting double SnO2 layer structure containing the SnO2 deposited layer and the SnO2 spin-coating layer is subjected to a first annealing treatment in air at a temperature of 80-100℃ to obtain the electron transport layer of the flexible perovskite solar cell. The method for obtaining the SnO2 dispersion doped with glycine hydrochloride includes: An aqueous dispersion of SnO2 was added to a deionized aqueous solution of glycine hydrochloride and mixed thoroughly to obtain the SnO2 dispersion of the doped glycine hydrochloride.

2. The preparation method according to claim 1, characterized in that, in, The thickness of the SnO2 deposited layer is 18-50 nm; and / or the thickness of the SnO2 spin coating is 20-30 nm.

3. The preparation method according to claim 2, characterized in that, The thickness of the SnO2 deposition layer is 30 nm; and / or the thickness of the SnO2 spin coating layer is 25-35 nm.

4. The preparation method according to claim 1, characterized in that, The concentration of SnO2 in the aqueous dispersion of SnO2 is 10-20 wt%; the volume ratio of the deionized aqueous solution of glycine hydrochloride to the aqueous dispersion of SnO2 is 4-6:

1.

5. The preparation method according to claim 1, characterized in that, in, The atomic layer deposition method includes: at a pressure of 2×10 -4 Pa-4×10 -4 Under the conditions of Pa, carrier gas flow rate of 20-40 sccm, and temperature of 80-100℃, the following are performed: (a) pulse injection of ultrapure water for 0.01-0.02s, followed by a 3-5s wait; (b) pulse injection of tetrakis(dimethylamino)tin source for 0.05-0.15s, followed by a 3-5s wait; then repeating (a)-(b) 200-300 times, followed by natural cooling to 55-65℃; and / or, the spin coating includes: spin coating the SnO2 dispersion doped with glycine hydrochloride onto the SnO2 deposition layer at a rotation speed of 4000-5000 rpm and an acceleration rate of 1000-2500 rpm / s.

6. The preparation method according to claim 1, characterized in that, The substrate is selected from polyethylene terephthalate coated indium tin oxide conductive material.

7. The preparation method according to claim 1, characterized in that, It includes: (1) A pretreated substrate was obtained by irradiating a polyethylene terephthalate-coated indium tin oxide conductive material substrate with ultraviolet light. (2) The flexible perovskite solar cell electron transport layer is prepared on the pretreated substrate to obtain a substrate containing the electron transport layer; (3) Dissolve formamidin hydroiodide, methylamine chloride, and lead iodide in a mixture of N,N-dimethylformamide and dimethyl sulfoxide to form a perovskite precursor solution. Spin coat the solution onto the substrate containing the electron transport layer. Add chlorobenzene dropwise during the spin coating process. After spin coating is completed, perform a second annealing treatment to obtain the substrate containing the perovskite layer. (4) Dissolve the passivating agent n-butylammonium iodide in isopropanol to obtain a passivation precursor solution, spin-coat it onto the substrate of the perovskite layer, and perform a third annealing treatment after spin-coating to obtain a substrate containing a passivation layer. (5) Dissolve 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene in chlorobenzene, then add acetonitrile solution of 4-tert-butylpyridine and lithium bis(trifluoromethane)sulfonylimide to obtain hole precursor solution, spin-coat it onto the substrate containing the passivation layer, and dry it after spin-coating to obtain substrate containing hole transport layer; (6) Silver is deposited as a metal electrode on the substrate containing the hole transport layer by thermal evaporation to obtain a flexible perovskite solar cell. The second annealing treatment is performed at a temperature of 80-100℃ for 10-40 minutes; and / or the third annealing treatment is performed at a temperature of 70-90℃ for 1-10 minutes.

8. The preparation method according to claim 7, characterized in that, In the perovskite precursor solution, the volume ratio of N,N-dimethylformamide and dimethyl sulfoxide is 1:4, the concentration of methylamine chloride is 0.1-1.0 mol / ml, the concentration of formamidinium hydroiodate is 1.0-2.0 mol / ml, and the concentration of lead iodide is 1.0-2.0 mol / ml; and / or, in the passivation precursor solution, the concentration of n-butylammonium iodide is 0.5-5 mg / mL.

9. The preparation method according to claim 7, characterized in that, The deposition rate of the deposited silver is Its thickness is 50-200nm.

10. A flexible perovskite solar cell prepared by the method according to any one of claims 1-9.

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