A low-temperature synthesis method of modified tin dioxide nanoparticles for perovskite solar cells

Abstract

The application belongs to the field of inorganic nanomaterials, and particularly relates to a low-temperature synthesis method of modified tin dioxide nanoparticles for perovskite solar cells, which comprises the following steps: dispersing a water-soluble salt or hydrate of tin, urea and a metal salt modifier in water; and obtaining a modified SnO2 nanoparticle dispersion liquid by reacting at 15-30 DEG C for 3-4 days; the metal salt modifier is a metal salt of potassium, cesium, magnesium and / or zirconium. The modified SnO2 nanoparticles can promote the transmission and extraction of electrons in the solar cell, inhibit the recombination loss of the perovskite solar cell, and thus improve the power conversion efficiency and stability of the perovskite solar cell when the modified SnO2 nanoparticles are used as an electron transport layer to prepare the perovskite solar cell.

Description

Technical Field

[0001] This invention belongs to the field of inorganic nanomaterials, specifically relating to a low-temperature synthesis method for modified tin dioxide nanoparticles for perovskite solar cells. Background Technology

[0002] Over the past decade or so, organic-inorganic halide perovskite solar cells (PSCs) have attracted widespread attention due to their excellent power conversion efficiency (PCE), which has now exceeded 26%.

[0003] For single-junction photocells (PSCs), the device structure includes both nip and pin structures. In nip PSCs, the perovskite photosensitive layer is deposited on n-type electron transport layers (ETLs). The surface morphology and chemical properties of the ETLs directly affect the quality of the perovskite layer and thus directly influence the photovoltaic performance and stability of the PSCs. To date, ETLs generally include n-type semiconductor oxide materials (such as TiO2, SnO2, ZnO, Zn2SnO4, and BaSnO3) and organic materials (such as C). 60 (and its derivatives). Highly efficient ETL materials require high transmittance, high conductivity, high electron mobility, and an appropriate work function. Studies have shown that tightly packed TiO2 and mesoporous TiO2 stacked ETL structures are excellent electron transport layers for high-efficiency nip-type PSCs. However, TiO2 itself has some drawbacks, such as photocatalytic activity under illumination and the need for high-temperature annealing (above 350℃) to achieve appropriate crystallinity, which limits its further development in PSCs. Therefore, researchers urgently need to develop high-performance ETL materials with low cost, good reproducibility, and good chemical stability.

[0004] Compared to TiO2, SnO2 (tin dioxide) possesses a deeper conduction band, a wider band gap (3.6-4.1 eV), and higher electron mobility, which are beneficial for electron transport and reducing interfacial contact barriers. It is foreseeable that designing methods for preparing SnO2 nanomaterials and researching simple and easy-to-implement synthesis strategies will undoubtedly greatly promote the development of perovskite solar cells. However, SnO2 nanomaterials suffer from low photoelectric conversion efficiency; therefore, overcoming this technical problem has become an urgent issue for those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a low-temperature synthesis method for modified tin dioxide nanoparticles for perovskite solar cells. By modifying the SnO2 colloid prepared by the existing sol-gel method, in-situ passivation of defect states in the electron transport layer is achieved, thereby improving the performance of the electron transport layer, improving the interfacial contact between the electron transport layer and the perovskite light absorption layer, and ultimately improving the performance of the solar cell.

[0006] The low-temperature synthesis method of modified tin dioxide nanoparticles for perovskite solar cells according to the present invention includes the following steps: dispersing a water-soluble salt or hydrate of tin, urea, and a metal salt modifier in water; reacting at 15-30℃ for 3-4 days to obtain a modified SnO2 nanoparticle dispersion; wherein the metal salt modifier is a metal salt of potassium, cesium, magnesium, and / or zirconium, and the molar ratio of the metal salt modifier to SnO2 is (1.0-4):100.

[0007] Furthermore, the water-soluble salt or hydrate of tin is selected from tin dichloride or tin dichloride dihydrate.

[0008] Furthermore, the molar ratio of the water-soluble salt or hydrate of tin, urea, and metal salt modifier is 1:1:(0.01 to 0.04).

[0009] Furthermore, metal salt modifiers that meet the above conditions may include, but are not limited to: potassium carbonate, potassium nitrate, potassium acetate, potassium sulfate, potassium chloride, cesium carbonate, cesium nitrate, cesium acetate, cesium sulfate, cesium chloride, magnesium carbonate, magnesium nitrate, magnesium acetate, magnesium sulfate, magnesium chloride, zirconium carbonate, zirconium nitrate, zirconium acetate, zirconium sulfate, zirconium chloride, and other metal salts of different valence states.

[0010] Furthermore, the preferred metal salt modifiers of the present invention are potassium carbonate, cesium carbonate, magnesium sulfate and / or zirconium chloride.

[0011] Furthermore, the preferred metal salt modifier of this invention is a combination of cesium carbonate and magnesium sulfate; preferably, the molar ratio of cesium to magnesium is (3-4):(0.4-0.6). Using this preferred embodiment, the short-circuit current density and photoelectric conversion efficiency of the battery can be significantly improved.

[0012] The present invention also provides modified SnO2 nanoparticles obtained by the above-described low-temperature synthesis method.

[0013] The present invention relates to the preparation process of modified SnO2 nanoparticles in electron transport layer materials, wherein the preparation process is constant temperature stirring.

[0014] The modified SnO2 electron transport layer obtained by the modification method described in this invention can be used to prepare high-efficiency perovskite solar cells, promote the transport and extraction of electrons in solar cells, improve the utilization rate of solar photons in perovskite solar cells, and thus improve the photoelectric conversion efficiency and other performance of perovskite solar cells.

[0015] Therefore, the present invention further provides a high-efficiency perovskite solar cell using the modified SnO2 electron transport material described in the present invention. The device structure of the perovskite solar cell, from bottom to top, includes: a transparent substrate and an electrode on the transparent substrate, a SnO2 electron transport layer deposited on the electrode, a perovskite active layer deposited on the SnO2 electron transport layer, a hole transport layer deposited on the perovskite active layer, and a metal electrode. The perovskite active layer can be composed of any perovskite material system, and the hole transport layer can be composed of any inorganic or organic hole transport material.

[0016] Beneficial Effects: The SnO2 electron transport material modification method for perovskite solar cells of this invention improves the electrical performance of the electron transport layer, enhances the contact between the electron transport layer and the active layer, and achieves in-situ defect passivation of the SnO2 electron transport layer. Applying the modified SnO2 electron transport material to solar cells can result in higher charge extraction and transport efficiency, suppress non-radiative recombination losses, and improve the electron collection efficiency and power conversion efficiency of the device. Using the modified SnO2 electron transport material of this invention, without introducing new interfacial contacts, not only can the performance of solar cells be effectively improved, but good compatibility with existing solar cells can also be achieved.

[0017] JV Test results show that, compared with unmodified SnO2 materials, applying the modified SnO2 electron transport material described in this invention to perovskite solar cells can improve the photoelectric conversion efficiency of perovskite solar cells by at least 5%; in particular, using SnO2 electron transport materials modified with both Cs and Mg can improve the photoelectric conversion efficiency of perovskite solar cells by at least 18%. Attached Figure Description

[0018] Figure 1 These are elemental analysis photographs of SnO2 nanoparticles prepared in Examples 1, 2, 3, 4 and Comparative Example 1 of this invention;

[0019] Figure 2 These are SEM images of the morphology of SnO2 nanoparticles prepared in Examples 1, 2, 3, 4 and Comparative Example 1 of this invention.

[0020] Figure 3 These are the methods used in Examples 1 and 2 and Comparative Example 1 of the present invention for preparing SnO2 nanoparticles. I- V Line graph;

[0021] Figure 4 These are the methods used in Examples 3 and 4 and Comparative Example 1 of the present invention for preparing SnO2 nanoparticles. I - V Line graph;

[0022] Figure 5 These are the fluorescence spectra of perovskite films deposited on the surface of SnO2 nanoparticles prepared in Examples 1, 2 and Comparative Example 1 of this invention;

[0023] Figure 6 This invention relates to the preparation of perovskite solar cells using SnO2 nanoparticles as the electron transport layer, as described in Examples 1 and 1 of the present invention. J - V Line graph;

[0024] Figure 7 This invention relates to the preparation of perovskite solar cells using SnO2 nanoparticles as the electron transport layer, as described in Examples 2 and 1 of this invention. J - V Line graph;

[0025] Figure 8 This invention relates to the preparation of perovskite solar cells using SnO2 nanoparticles as the electron transport layer, as described in Examples 3 and 1 of the present invention. J - V Line graph;

[0026] Figure 9 This invention relates to the preparation of perovskite solar cells using SnO2 nanoparticles as the electron transport layer, as described in Examples 5 and 1 of this invention. J - V Line graph. Detailed Implementation

[0027] The following embodiments are merely preferred technical solutions of the present invention and are not intended to limit the present invention in any way. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0028] In all embodiments of the present invention, the electron transport layer is prepared on ITO or FTO conductive glass.

[0029] The patterned ITO and FTO conductive glass was thoroughly cleaned and then ultrasonically cleaned in deionized water, acetone, and isopropanol for 20 minutes each. It was then baked overnight in a 60°C oven to remove excess solvent. Finally, the clean conductive glass was exposed to ultraviolet ozone for 15 minutes to improve its work function.

[0030] Example 1: Weigh 676 mg of tin dichloride dihydrate, 180 mg of urea, and 8.29 mg of potassium carbonate, place them in a glass sample bottle, add 20 ml of deionized water, place the bottle in a magnetic stirrer, and stir vigorously at room temperature until the mixture is homogeneous to obtain a white emulsion suspension. React at room temperature for 3-4 days to prepare a yellow transparent SnO2 nanoparticle colloidal solution, labeled as K-SnO2 (the molar ratio of K ions to Sn is 4:100).

[0031] Example 2: Weigh 676 mg of tin dichloride dihydrate, 180 mg of urea, and 18.5 mg of cesium carbonate into a glass sample bottle, add 20 ml of deionized water, place the bottle in a magnetic stirrer, and stir vigorously at room temperature until the mixture is homogeneous to obtain a white emulsion suspension. React at room temperature for 3-4 days to prepare a yellow transparent SnO2 nanoparticle colloidal solution, labeled as Cs-SnO2 (the molar ratio of Cs ions to Sn is 3.8:100).

[0032] Example 3: Weigh 676 mg of tin dichloride dihydrate, 180 mg of urea, and 7.22 mg of magnesium sulfate, place them in a glass sample bottle, add 20 ml of deionized water, place the bottle in a magnetic stirrer, and stir vigorously at room temperature until the mixture is homogeneous to obtain a white emulsion suspension. React at room temperature for 3-4 days to prepare a yellow transparent SnO2 nanoparticle colloidal solution, labeled as Mg-SnO2 (the molar ratio of Mg ions to Sn is 2:100).

[0033] Example 4: Weigh 676 mg of tin dichloride dihydrate, 180 mg of urea, and 13.38 mg of zirconium chloride, place them in a glass sample bottle, add 20 ml of deionized water, place the bottle in a magnetic stirrer, and stir vigorously at room temperature until the mixture is homogeneous to obtain a white emulsion suspension. React at room temperature for 3-4 days to prepare a yellow transparent SnO2 nanoparticle colloidal solution, labeled as Zr-SnO2 (the molar ratio of Zr ions to Sn is 1.9:100).

[0034] Example 5: Weigh 676 mg of tin dichloride dihydrate, 180 mg of urea, 1.81 mg of magnesium sulfate, and 17.04 mg of cesium carbonate, place them in a glass sample bottle, add 20 ml of deionized water, place the bottle in a magnetic stirrer, and stir vigorously at room temperature until the mixture is homogeneous to obtain a white emulsion suspension. React at room temperature for 3-4 days to prepare a yellow transparent SnO2 nanoparticle colloidal solution, labeled as Cs-Mg-SnO2 (the molar ratio of Cs ions, Mg and Sn is 3.3:0.5:100).

[0035] Comparative Example 1: Weigh 676 mg of tin dichloride dihydrate and 180 mg of urea, place them in a glass sample bottle, add 20 ml of deionized water, place the bottle in a magnetic stirrer, and stir vigorously at room temperature until the mixture is homogeneous to obtain a white emulsion suspension. React at room temperature for 3-4 days to prepare a yellow transparent SnO2 nanoparticle colloidal solution, labeled as P-SnO2.

[0036] Test Method 1: Elemental analysis of P-SnO2, K-SnO2, Cs-SnO2, Mg-SnO2, and Zr-SnO2 prepared in Comparative Example 1, Example 1, Example 2, Example 3, and Example 4 was performed using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The results are as follows: Figure 1 The results are shown.

[0037] The analysis results show that K + Cs + Mg 2+ Zr 4+ The uniform distribution of metal ions of different valence states in the doped SnO2 nanoparticles proves that metal ions of different valence states have been successfully incorporated into SnO2, and also demonstrates the effectiveness and operability of the doping strategy of metal ions of different valence states.

[0038] Test Method 2: Using scanning electron microscopy (SEM), the microstructures of P-SnO2, K-SnO2, Cs-SnO2, Mg-SnO2, and Zr-SnO2 prepared in Comparative Example 1, Example 1, Example 2, Example 3, and Example 4 were tested and analyzed, and the results were as follows: Figure 2 The SEM image shown.

[0039] Test results show that K + Cs + Mg 2+ Zr 4+ The microstructure of SnO2 nanoparticles doped with metal ions of different valence states was significantly altered. Among them, Cs... + The Cs-SnO2 nanoparticles obtained after doping have a more uniform particle size and a more uniform distribution on the substrate. The more uniform particle size and more uniform coverage will improve the interfacial contact between the electron transport layer and the perovskite light-absorbing layer, reduce the interfacial barrier, improve the crystallinity of the perovskite, and ultimately improve the performance of perovskite solar cells.

[0040] Test Method 3: Using the four-probe method, the conductivity of P-SnO2, K-SnO2, and Cs-SnO2 prepared in Comparative Example 1, Example 1, and Example 2 was analyzed, and the results were as follows: Figure 3 The current-voltage characteristic curve shown is (IV).

[0041] The test results show that K+ Cs + The electrical conductivity of ion-doped K-SnO2 and Cs-SnO2 materials is significantly higher than that of undoped P-SnO2. This higher conductivity facilitates faster electron transport in perovskite solar cells, thereby improving their power conversion efficiency.

[0042] The conductivity of P-SnO2, Mg-SnO2, and Zr-SnO2 prepared in Comparative Example 1, Example 3, and Example 4 was analyzed using the four-probe method, and the results were as follows: Figure 4 The current-voltage characteristic curve shown is (IV).

[0043] Test results show that Mg 2+ Zr 4+ The electrical conductivity of ion-doped Mg-SnO2 and Zr-SnO2 materials is significantly higher than that of undoped P-SnO2. This higher conductivity facilitates faster electron transport in perovskite solar cells, thereby improving their power conversion efficiency.

[0044] Test Method 4: Using steady-state fluorescence spectroscopy (PL), P-SnO2, K-SnO2, and Cs-SnO2 prepared in Comparative Example 1, Example 1, and Example 2 were used as electron transport layers, and the PL intensity of the perovskite films was compared to obtain the results. Figure 5 The results are shown.

[0045] The comparative results show that the electron spectral density (PL) of the perovskite films prepared on the surface of K-SnO2 and Cs-SnO2 transport layers is significantly reduced. This reduced PL intensity implies more efficient electron extraction and transport capabilities of the K-SnO2 and Cs-SnO2 transport layers, which is beneficial for improving the electron collection efficiency of perovskite solar cells and ultimately enhancing their power conversion efficiency.

[0046] Test Method 5: Using P-SnO2 prepared in Comparative Example 1 as the electron transport layer, a perovskite solar cell with a device structure of Glass / ITO / P-SnO2 / CsPbI3 / P3HT / MoO3 / Ag was fabricated.

[0047] Using K-SnO2 prepared in Example 1 as the electron transport layer, a perovskite solar cell with a device structure of Glass / ITO / K-SnO2 / CsPbI3 / P3HT / MoO3 / Ag was fabricated.

[0048] At AM 1.5G 100mW / cm 2 The organic solar cells prepared under the test conditions JV Performance curves, results as follows Figure 6 As shown.

[0049] The battery performance parameters using P-SnO2 as the electron transport layer are: open-circuit voltage 1.07V, short-circuit current density 17.85mA / cm². 2 The fill factor is 68.92% and the power conversion efficiency is 13.16%.

[0050] The battery performance parameters using K-SnO2 as the electron transport layer are: open-circuit voltage 1.07V, short-circuit current density 18.82mA / cm². 2 The fill factor is 68.86% and the power conversion efficiency is 13.87%.

[0051] Compared with batteries using P-SnO2 as the electron transport layer, batteries using K-SnO2 as the electron transport layer have a 5.6% higher short-circuit current density and a 5.4% higher photoelectric conversion efficiency.

[0052] Test Method 6: Using P-SnO2 prepared in Comparative Example 1 as the electron transport layer, a perovskite solar cell with a device structure of Glass / ITO / P-SnO2 / CsPbI3 / P3HT / MoO3 / Ag was fabricated.

[0053] Using Cs-SnO2 prepared in Example 2 as the electron transport layer, a perovskite solar cell with a device structure of Glass / ITO / Cs-SnO2 / CsPbI3 / P3HT / MoO3 / Ag was fabricated.

[0054] At AM 1.5G 100mW / cm 2 The organic solar cells prepared under the test conditions JV Performance curves, results as follows Figure 7 As shown.

[0055] The battery performance parameters using P-SnO2 as the electron transport layer are: open-circuit voltage 1.07V, short-circuit current density 17.85mA / cm². 2 The fill factor is 68.92% and the power conversion efficiency is 13.16%.

[0056] The battery performance parameters using Cs-SnO2 as the electron transport layer are: open-circuit voltage 1.09V, short-circuit current density 19.46mA / cm². 2 The fill factor is 68.96% and the power conversion efficiency is 14.62%.

[0057] Compared with batteries using P-SnO2 as the electron transport layer, batteries using Cs-SnO2 as the electron transport layer have a 9.2% higher short-circuit current density and an 11.1% higher photoelectric conversion efficiency.

[0058] Test Method 7: Using P-SnO2 prepared in Comparative Example 1 as the electron transport layer, a perovskite solar cell with a device structure of Glass / ITO / P-SnO2 / CsPbI3 / P3HT / MoO3 / Ag was fabricated.

[0059] Using Mg-SnO2 prepared in Example 3 as the electron transport layer, a perovskite solar cell with a device structure of Glass / ITO / Mg-SnO2 / CsPbI3 / P3HT / MoO3 / Ag was fabricated.

[0060] At AM 1.5G 100mW / cm 2 The organic solar cells prepared under the test conditions JV Performance curves, results as follows Figure 8 As shown.

[0061] The battery performance parameters using P-SnO2 as the electron transport layer are: open-circuit voltage 1.07V, short-circuit current density 17.85mA / cm². 2 The fill factor is 68.92% and the power conversion efficiency is 13.16%.

[0062] The battery performance parameters using Mg-SnO2 as the electron transport layer are: open-circuit voltage 1.09V, short-circuit current density 19.16mA / cm². 2 The fill factor is 68.76% and the power conversion efficiency is 14.36%.

[0063] Compared with batteries using P-SnO2 as the electron transport layer, batteries using Mg-SnO2 as the electron transport layer have a 7.5% higher short-circuit current density and a 9.1% higher photoelectric conversion efficiency.

[0064] Test Method 8: Using P-SnO2 prepared in Comparative Example 1 as the electron transport layer, a perovskite solar cell with a device structure of Glass / ITO / P-SnO2 / CsPbI3 / P3HT / MoO3 / Ag was fabricated.

[0065] Using Cs-Mg-SnO2 prepared in Example 5 as the electron transport layer, a perovskite solar cell with a device structure of Glass / ITO / Cs-Mg-SnO2 / CsPbI3 / P3HT / MoO3 / Ag was fabricated.

[0066] At AM 1.5G 100mW / cm 2 The organic solar cells prepared under the test conditions JV Performance curves, results as follows Figure 9 As shown.

[0067] The battery performance parameters using P-SnO2 as the electron transport layer are: open-circuit voltage 1.07V, short-circuit current density 17.85mA / cm². 2 The fill factor is 68.92% and the power conversion efficiency is 13.16%.

[0068] The battery performance parameters using Cs-Mg-SnO2 as the electron transport layer are: open-circuit voltage 1.10V, short-circuit current density 19.88mA / cm². 2 The fill factor is 71.43% and the power conversion efficiency is 15.56%.

[0069] Compared with batteries using P-SnO2 as the electron transport layer, batteries using Cs-Mg-SnO2 as the electron transport layer have an 11.5% higher short-circuit current density and an 18.2% higher photoelectric conversion efficiency.

[0070] The preferred embodiments of the present invention have been described above, but are not intended to limit the invention. Those skilled in the art can make modifications and variations to the embodiments disclosed herein without departing from the scope and spirit of the invention.

Claims

1. A method for low temperature synthesis of modified tin dioxide nanoparticles for perovskite solar cells, characterized by, The process includes the following steps: dispersing a water-soluble salt of tin or its hydrate, urea, and a metal salt modifier in water; reacting at 15-30℃ for 3-4 days to obtain a modified SnO2 nanoparticle dispersion; wherein the metal salt modifier is a combination of cesium carbonate and magnesium sulfate, wherein the molar ratio of cesium to magnesium is (3-4):(0.4-0.6), and the molar ratio of the metal salt modifier to SnO2 is (1.0-4):

100.

2. The low temperature synthesis method of claim 1, wherein, The reaction was carried out with continuous stirring in air at room temperature.

3. The low-temperature synthesis method according to claim 1, characterized in that, The molar ratio of the water-soluble salt of tin or its hydrate, urea and the metal salt modifier is 1:1:(0.01-0.04).

4. The low-temperature synthesis method according to claim 1, characterized in that, The water-soluble salt of tin or its hydrate is selected from tin dichloride or tin dichloride dihydrate.

5. Modified SnO2 nanoparticles obtained by the low-temperature synthesis method according to any one of claims 1-4.

6. The application of the modified SnO2 nanoparticles as described in claim 5 as an electron transport layer material in the preparation of perovskite solar cells.

7. A perovskite solar cell, characterized in that, From bottom to top, the structure comprises: a transparent substrate and an electrode on the transparent substrate, an electron transport layer deposited on the electrode, a perovskite active layer deposited on the electron transport layer, a hole transport layer deposited on the perovskite active layer, and a metal electrode. The electron transport layer is prepared using the modified SnO2 nanoparticles as described in claim 5. The perovskite active layer is composed of any perovskite system material, and the hole transport layer is composed of any inorganic or organic hole transport material.

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