Method for preparing high-quality sno2 amorphous-nanopillar hetero-phase by ald and application thereof

Abstract

The application discloses a method for preparing high-quality SnO2 amorphous-nanopillar heterophase by ALD and application thereof, and relates to the technical field of perovskite solar cells, and comprises the following steps: S1, providing a substrate and pre-treating the same to obtain a pre-treated substrate; S2, spin-coating a tin oxide nanocrystal solution on the pre-treated substrate to obtain a pre-treatment film layer; S3, performing plasma sputtering etching on the surface of the pre-treatment film layer to obtain a first processing piece; S4, preheating the first processing piece in an ALD, using tetraethyltin and H2O2 as reaction sources, growing tin oxide nanocrystals on the surface of the first processing piece, controlling the reaction temperature and the deposition speed of a chamber to obtain tin oxide amorphous-nanopillar heterophase, and completing the preparation. The application further comprises application of the method to preparation of perovskite solar cells. The method simplifies the preparation process, is environment-friendly, and has less internal defects of the prepared heterophase, and the device performance is more superior.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and in particular to a method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phases by ALD. Background Art

[0002] Perovskite solar cells widely utilize planar SnO2 polycrystals and nanocrystals. However, perovskite cells based on planar electron transport layers suffer from the inability to simultaneously achieve efficient solar light absorption and efficient transport of photogenerated carriers. One-dimensional (1D) metal oxide nanopillar structures (such as TiO2, ZnO, and SnO2) act as direct pathways for electron transport, enhancing carrier transport between the perovskite and transport layers. Furthermore, compared to mesoporous structures, 1D nanopillar structures facilitate more complete perovskite filling, forming a favorable heterojunction interface.

[0003] However, SnO2 electron transport layers are typically prepared using a solution process. This method is not only cumbersome, characterized by poor stability and difficult morphology control, but also involves high pollution and cost due to the use of chemical reagents. Some studies have used ALD to deposit SnO2 thin films using tetraethyltin and H2O2, but the resulting SnO2 films are highly defective and amorphous, hindering carrier transport and exhibiting significant defects. Summary of the Invention

[0004] The present invention aims to address the problems of existing SnO2 electron transport layer preparation methods, which are complex, unstable, difficult to control morphology, and require high chemical reagent pollution and cost. The present invention provides a method for growing SnO2 amorphous-crystalline nanopillar heterophases using ALD. The resulting SnO2 amorphous-crystalline heterophase can better promote carrier transport, reduce non-radiative recombination in the transport layer, and enhance device light absorption, thereby improving device performance.

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0006] A method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD, comprising the following steps: S1, providing a substrate and pre-treating it to obtain a pre-treated substrate; S2, spin-coating a tin oxide nanocrystal solution on the pre-treated substrate to obtain a pre-treated film layer; S3, plasma sputtering etching the surface of the pre-treated film layer to obtain a first treated part; S4, placing the first treated part in an ALD for preheating, using tetraethyltin and H2O2 as reaction sources, growing tin oxide nanocrystals on the surface of the first treated part, controlling the chamber reaction temperature and deposition rate to obtain the tin oxide amorphous-nanopillar heterogeneous phase, and completing the preparation.

[0007] Furthermore, in S1, the substrate is a transparent conductive substrate that can withstand high temperatures above 150°C.

[0008] Furthermore, the S1 specifically includes providing a substrate and placing the substrate in a UV light and ozone cleaning machine for cleaning for 10 to 18 minutes.

[0009] Furthermore, in S2, the tin oxide nanocrystal solution is spin-coated on the substrate at a rotation speed of 2200-2400 rpm and a spin-coating time of 25-35 s. After spin-coating, the solution is annealed for 25-35 min to a temperature of 145-155°C.

[0010] Furthermore, in S2, the tin oxide nanocrystal solution is a tin oxide nanocrystal aqueous solution with a concentration of 12 to 15 mg / ml.

[0011] Furthermore, in S3, the plasma sputtering etching uses nitrogen as an inert gas, with a flow rate of 900-1100 sccm, a chamber pressure of 1.3-1.45 torr, and a power of 700 W.

[0012] Furthermore, in S4, preheating is performed at 350° C. for 8 to 12 minutes.

[0013] Furthermore, in S4, the reaction temperature of the chamber is controlled to be 300-400° C., and the deposition rate is 0.05 nm / s.

[0014] Furthermore, the method further includes performing surface modification on the tin oxide amorphous-nanopillar heterogeneous phase obtained in S4 to complete the preparation.

[0015] The present invention also provides an application of the method for preparing high-quality SnO2 amorphous-nanopillar heterophase based on the above-mentioned ALD, which is used for the preparation of perovskite solar cells.

[0016] Compared with the prior art, the advantages of the present invention are:

[0017] 1. This invention relates to a method for preparing high-quality SnO2 amorphous-nanopillar heterophases using ALD. This method utilizes ALD to grow SnO2 amorphous-nanopillar heterophases for use as electron transport layers in solar cells. This method simplifies the SnO2 preparation process and reduces environmental pollution. The prepared heterophases also have fewer internal defects and can enhance carrier transport in perovskite cells. It also reduces non-radiative recombination in the transport layer and enhances light absorption in the device, thereby improving device performance.

[0018] 2. The application of the ALD method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase involved in the present invention can be used in the preparation of perovskite solar cells. The preparation method is simple, has wide applicability, and has a large application space. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the nanocrystalline structure after plasma sputtering etching of the tin oxide surface in Example 1 of the present invention.

[0020] Figure 2 Schematic diagram of the structure of the tin oxide amorphous-nanopillar heterogeneous phase in Example 1 of the present invention.

[0021] Figure 3 Scanning electron microscope image of the device 1 prepared in Example 1 of the present invention Figure 1 .

[0022] Figure 4 Scanning electron microscope image of the device 1 prepared in Example 1 of the present invention Figure 2 .

[0023] Figure 5 Schematic diagram comparing the energy conversion efficiency measurement results of device 1 and device 3 in Experimental Example 2 of the present invention.

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0025] Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention. DETAILED DESCRIPTION

[0026] The present invention provides a method for preparing high-quality SnO2 amorphous-nanopillar heterophase by ALD, comprising the following steps: S1, providing a substrate and pre-treating the substrate to obtain a pre-treated substrate; S2, spin-coating a tin oxide nanocrystal solution on the pre-treated substrate to obtain a pre-treated film layer; S3, performing plasma sputtering etching on the surface of the pre-treated film layer to obtain a first treated part; S4, placing the first treated part in an ALD for preheating, using tetraethyltin and H2O2 as reaction sources, growing tin oxide nanocrystals on the surface of the first treated part, controlling the reaction temperature and deposition rate of the chamber to obtain the tin oxide amorphous-nanopillar heterophase, and completing the preparation.

[0027] It can be understood that ALD uses tetraethyltin and H2O2 as sources to grow tin oxide nanocrystals. By controlling the reaction temperature and deposition rate in the chamber, epitaxial growth occurs on the surface of the tin oxide nanocrystals, forming a nanopillar structure. On the substrate without attached nanocrystals, disordered amorphous tin oxide grows, ultimately resulting in a tin oxide amorphous-nanopillar heterogeneous phase.

[0028] Existing SnO2 thin films grown by solution methods are difficult to control in terms of morphology, contain numerous internal defects, and exhibit poor carrier extraction capabilities. Furthermore, the preparation process is complex and environmentally polluting. Furthermore, SnO2 thin films deposited directly by ALD using tetraethyltin and H2O2 exhibit numerous defects and are amorphous, hindering carrier transport.

[0029] The preparation method of the present invention utilizes tin oxide nanocrystals as seed crystals and ALD-grown SnO2 amorphous-nanopillar heterostructures as the electron transport layer of solar cells. This method simplifies the SnO2 preparation process and reduces environmental pollution. Furthermore, the heterostructure produced has fewer internal defects, promoting carrier transport in perovskite cells and enhancing the device's light absorption performance.

[0030] In some embodiments of the present invention, in S1, the substrate is a transparent conductive substrate that can withstand high temperatures above 150°C.

[0031] In some specific embodiments, the substrate is preferably a FTO or ITO substrate.

[0032] In certain embodiments of the present invention, the step S1 specifically includes providing a substrate and placing the substrate in a UV light and ozone cleaning machine for cleaning for 10 to 18 minutes. Specifically, the cleaning time is preferably 15 minutes.

[0033] In certain embodiments of the present invention, in S2, the tin oxide nanocrystal solution is spin-coated on the substrate at a rotation speed of 2200-2400 rpm, a spin-coating time of 25-35 s, and annealing for 25-35 min after spin-coating, annealing to a temperature of 145-155° C. Specifically, the tin oxide nanocrystal solution is spin-coated on the substrate at a rotation speed of preferably 2300 rpm, a spin-coating time of preferably 30 s, and a spin-coating annealing time of preferably 30 min after spin-coating, annealing to a temperature of 150° C.

[0034] In certain embodiments of the present invention, in S2, the tin oxide nanocrystal solution is an aqueous solution of tin oxide nanocrystals having a concentration of 12 to 15 mg / ml. Specifically, the tin oxide nanocrystal solution is preferably an aqueous solution of tin oxide nanocrystals having a concentration of 14 mg / ml. The tin oxide nanocrystals are commercially available from Shanghai Aladdin Biochemical Technology Co., Ltd., with an average particle size of <100 nm and a purity of 99.9%.

[0035] In certain embodiments of the present invention, in S3, the plasma sputter etching uses nitrogen as an inert gas, with a flow rate of 900 to 1100 sccm, a chamber pressure of 1.3 torr torr, and a power of 700 W. Specifically, the plasma sputter etching uses nitrogen as an inert gas, with a flow rate of preferably 1000 sccm, a chamber pressure of preferably 1.4 torr, and a power of 700 W.

[0036] In certain embodiments of the present invention, in S4, the preheating is performed at 350° C. for 8 to 12 minutes. Specifically, the preheating time is preferably 10 minutes.

[0037] In some embodiments of the present invention, in S4, the reaction temperature of the chamber is controlled to be 300-400° C., and the deposition rate is 0.05 nm / s.

[0038] In certain embodiments of the present invention, in S4, the reaction source H2O2 is 50 wt% H2O2.

[0039] In certain embodiments of the present invention, in S4, the reaction pressure using tetraethyltin and H2O2 as reaction sources is preferably 1.8 torr.

[0040] In certain embodiments of the present invention, the method further comprises performing surface modification on the tin oxide amorphous-nanopillar heterogeneous phase obtained in S4 to complete the preparation.

[0041] In certain embodiments of the present invention, the surface modification of the heterogeneous phase is performed using a formamidine oxalate solution (FOA) to modify the heterogeneous phase surface. The formamidine oxalate solution used has a concentration of 3 mg / ml (the solvent is purified water). The modification is performed by spin coating the tin oxide amorphous-nanopillar heterogeneous phase with the formamidine oxalate solution, preferably at a speed of 5000 rpm for 30 seconds. After spin coating, the heterogeneous phase is annealed on a hot plate at 150°C for 10 minutes.

[0042] It can be understood that the use of formamidine oxalate solution (FOA) to modify the heterogeneous phase surface can passivate tin oxide, while also reducing the oxygen vacancies and tin interstitial defects on the SnO2 surface and the FA+ / Pb2+ defects of the perovskite, thereby achieving the effect of improving the overall performance of the device.

[0043] In some embodiments, the formamidine oxalate solution FOA can be replaced with other buried interface passivation materials for normal perovskite cells.

[0044] The present invention also provides an application of the above-described method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phases using ALD, which is used to prepare perovskite solar cells. The method is simple, widely applicable, and has a wide range of applications.

[0045] Example 1

[0046] 1.1 Device preparation process

[0047] In this embodiment, the specific operations are:

[0048] S1. Provide an FTO substrate and place it in a UV light ozone cleaning machine for cleaning for 15 minutes.

[0049] S2, spin coating tin oxide nanocrystal solution on the substrate, preferably with a rotation speed of 2300 rpm, preferably with a spin coating time of 30 seconds, preferably with an annealing time of 30 minutes after spin coating, annealing to a temperature of 150°C, to obtain a pre-treated film layer. S3, plasma sputter etching is performed on the surface of the pre-treated film layer, using nitrogen as an inert gas, preferably with a flow rate of 1000 sccm, preferably with a chamber pressure of 1.4 torr, and a power of 700w. The first treated part is obtained, and the etched first treated nanocrystal structure is as shown Figure 1 shown.

[0050] S4. Place the first processing piece in an ALD process for preheating at 350° C. for 10 minutes. Use tetraethyltin and H 2 O 2 as reaction sources to grow tin oxide nanocrystals on the surface of the first processing piece.

[0051] The reaction temperature of the chamber is controlled at 300-400℃ and the deposition rate is 0.05nm / s. During the deposition process, epitaxial growth occurs on the surface of the tin oxide nanocrystals to form a nanocolumn structure; while the substrate without nanocrystals will grow disordered amorphous tin oxide. Figure 2 The tin oxide amorphous-nanopillar heterophase is shown.

[0052] S5. Since defects remain on the surface of the tin oxide amorphous-nanopillar heterophase prepared by ALD after step S4, formamidine oxalate is used to modify the heterophase surface. A formamidine oxalate solution is spin-coated on the surface of the tin oxide amorphous-nanopillar heterophase at a preferred speed of 5000 rpm for 30 seconds. After spin coating, the heterophase is annealed on a 150°C hotplate for 10 minutes. Device 1 is thus fabricated.

[0053] Comparative Example 1

[0054] Device 2 was obtained by growing SnO2 using a solution method commonly used in the prior art. The preparation method is as follows:

[0055] (1) Mix 275 mg of SnC, 12.2 mL of H2O, 1.25 mL of HCl, 1.25 g of urea, and 25 μL of TGA in 100 mL of deionized water.

[0056] (2) FTO glass (only FTO glass) cleaned in UV light UV ozone cleaner for 15 minutes was immersed in the above solution. The solution was heated in a 90°C oven for ≈4h (in this process, polycrystalline tin oxide grew on the FTO surface).

[0057] (3) The FTO glass with polycrystalline tin oxide grown on the surface was taken out of the solution, and then was ultrasonically cleaned in deionized water and isopropanol for 5 minutes, respectively, and was dried by air gun.

[0058] (4) The glass was annealed in air at 170°C (humidity = 25-35%) for 60 minutes to obtain device 2.

[0059] 1.1 Test operation

[0060] The device 1 prepared in Example 1 was characterized by scanning electron microscopy, and the electron micrograph is shown in Figure 3 、 Figure 4 .

[0061] 1.2 Result analysis

[0062] Referring to the electron micrograph of Figure 3 and Figure 4 , it can be seen that the surface structure of the device 1 prepared in Example 1 is uniform, and the surface is visible and uniform tin oxide amorphous-nanopillar heterogeneous phase structure. As can be seen from the electron micrograph, the device 1 prepared in Example 1 has excellent structure morphology.

[0063] Test Example 2: Performance test of the devices 1 and 2 prepared in Example 1 and Comparative Example

[0064] The devices 1 and 2 prepared in Example 1 and Comparative Example, respectively, were subjected to energy conversion efficiency (PCE) determination, and the determination results are shown in Figure 5 .

[0065] 2.2 Result analysis

[0066] Referring to the determination result graph of Figure 5 , it can be seen that the device 1 prepared in Example 1 has higher energy conversion efficiency, and the performance of the device 2 prepared in Comparative Example using the conventional method is better. It can be seen that the preparation method of the present case is more superior.

[0067] In summary, the present invention relates to a method for preparing high-quality SnO2 amorphous-nanopillar heterophases using ALD, utilizing tin oxide nanocrystals as seed crystals to grow the SnO2 amorphous-nanopillar heterophases as the electron transport layer of solar cells. This method simplifies the SnO2 preparation process and reduces environmental pollution. Furthermore, the prepared heterophases exhibit fewer internal defects, promoting carrier transport in perovskite cells and enhancing the device's light absorption performance. As demonstrated in Experimental Examples 1 and 2, the resulting devices exhibited fewer internal defects in the heterophases, resulting in improved device performance.

[0068] The above embodiment is merely one embodiment of the present invention, and its description is relatively specific and detailed, but it should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the scope of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the appended claims.

Claims

1. A method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD, characterized in that: The following steps are involved: S1. providing a substrate and pre-treating the substrate to obtain a pre-treated substrate; S2, spin coating a tin oxide nanocrystal solution on the pretreated substrate to obtain a pretreated film layer; S3, performing plasma sputtering etching on the surface of the pre-treated film layer to obtain a first treated part; S4. Place the first processing piece in ALD for preheating, use tetraethyltin and H2O2 as reaction sources, grow tin oxide nanocrystals on the surface of the first processing piece, control the chamber reaction temperature and deposition rate to obtain a tin oxide amorphous-nanopillar heterogeneous phase, and complete the preparation.

2. The method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD according to claim 1, characterized in that: In the above-mentioned S1, the substrate is a transparent conductive substrate capable of withstanding high temperatures above 150°C.

3. The method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD according to claim 1, characterized in that: Specifically, the step S1 includes providing a substrate and placing the substrate in a UV light and ozone cleaning machine for cleaning for 10 to 18 minutes.

4. The method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD according to claim 1, characterized in that: In S2, the tin oxide nanocrystal solution is spin-coated on the substrate at a rotation speed of 2200-2400 rpm for 25-35 seconds, and annealed for 25-35 minutes after spin coating to a temperature of 145-155°C.

5. The method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD according to claim 4, characterized in that: In S2, the tin oxide nanocrystal solution is a tin oxide nanocrystal aqueous solution with a concentration of 12 to 15 mg / ml.

6. The method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD according to claim 1, characterized in that: In S3, the plasma sputter etching uses nitrogen as an inert gas, with a flow rate of 900-1100 sccm, a chamber pressure of 1.3-1.45 torr, and a power of 700 W.

7. The method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD according to claim 1, characterized in that: In the above-mentioned S4, preheating is performed at 350° C. for 8 to 12 minutes.

8. The method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD according to claim 1, characterized in that: In the above-mentioned S4, the reaction temperature of the chamber is controlled to be 300-400° C., and the deposition rate is 0.05 nm / s.

9. The method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD according to claim 1, characterized in that: The method further includes performing surface modification on the tin oxide amorphous-nanopillar heterogeneous phase obtained in S4 to complete the preparation.

10. Application of the method for preparing high-quality SnO2 amorphous-nanopillar heterogeneous phase by ALD according to any one of claims 1 to 9, characterized in that: The method is used for preparing perovskite solar cells.

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