Perovskite solar cell and preparation method of electron transport layer thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method of an electron transport layer thereof, and belongs to the technical field of photovoltaic devices, and the preparation method comprises the following steps: dispersing SnO2 nano powder in absolute ethyl alcohol, and carrying out ultrasonic treatment to form SnO2 dispersion liquid; adjusting the pH value of the dispersion liquid to an acidic condition, and adding a siloxane coupling agent 3-aminopropyltrimethoxysilane to carry out a modification reaction; after centrifugal separation, carrying out vacuum drying to obtain SnO2 (at) APTMS nano particle powder; the preparation method comprises the following steps: dispersing SnO2 (at) APTMS nanoparticles and graphene oxide in absolute ethyl alcohol, performing ultrasonic treatment to form a SnO2 (at) APTMS: GO nanoparticle dispersion liquid, spin-coating the dispersion liquid on a substrate, and performing annealing treatment to form the SnO2 (at) APTMS: GO electron transport layer. The SnO2 nanoparticles are doped with graphene oxide to obtain the SnO2 (at) APTMS: GO electron transport layer, so that the conductivity of SnO2 and the performance of a PSCs device are further improved, and the problems of carrier recombination loss and interface instability are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic devices, and specifically relates to a perovskite solar cell based on a SnO2@APTMS:GO composite material and a method for preparing the electron transport layer thereof. Background Art

[0002] Perovskite solar cells (PSCs) have attracted considerable attention due to their low manufacturing costs and excellent photovoltaic properties, making them one of the most promising photovoltaic technologies. Among them, tin oxide (SnO2) has attracted widespread attention as an ideal material for the electron transport layer (ETL) of efficient and stable PSC devices due to its wide bandgap, high transmittance, low conduction band offset, low cost, and low-temperature processing.

[0003] In existing technologies, SnO2 exhibits inherent defects when used as a low-temperature processed electron transport layer (ETL). The interface with the perovskite light-absorbing layer contains numerous oxygen vacancies, surface hydroxyl groups, and unsaturated dangling bonds, which in turn impair electron transport, increase carrier recombination, and degrade device performance. These defects act as non-radiative recombination centers during carrier transport and extraction, trapping photogenerated carriers and forming deep energy-level traps, leading to significant losses in the open-circuit voltage (Voc) and fill factor (FF) of PSCs. Furthermore, they interact with the perovskite film as reactive sites, causing decomposition and phase transitions, and reducing device stability. Traditional surface passivation methods suffer from poor bonding stability, complex processes, or decreased conductivity, and fail to simultaneously address the conflict between defect passivation and charge transfer efficiency.

[0004] Therefore, optimizing the surface properties of the SnO2 electron transport layer and reducing the impact of interface defects on device performance are important ways to improve the photoelectric conversion efficiency and stability of PSCs. Summary of the Invention

[0005] To overcome the problems of carrier recombination loss and interface instability caused by SnO2 interface defects in the prior art, the present invention provides a method for preparing a perovskite solar cell and an electron transport layer thereof, which specifically includes the following contents:

[0006] A method for preparing an electron transport layer for a perovskite solar cell comprises the following steps:

[0007] S1, dispersing SnO2 nanopowder in anhydrous ethanol and forming a SnO2 dispersion after ultrasonic treatment;

[0008] S2. Adjust the pH of the dispersion to an acidic condition and add siloxane coupling agent 3-aminopropyltrimethoxysilane (APTMS) to carry out modification reaction;

[0009] S3, centrifugation and washing to remove unreacted products, followed by vacuum drying to obtain SnO2@APTMS nanoparticle powder;

[0010] S4, dispersing SnO2@APTMS nanoparticles and graphene oxide in anhydrous ethanol, and forming SnO2@APTMS:GO nanoparticle dispersion by ultrasonic treatment;

[0011] S5. Spin-coat the SnO2@APTMS:GO nanoparticle dispersion on the substrate and anneal to form a SnO2@APTMS:GO electron transport layer.

[0012] Furthermore, the amount of the siloxane coupling agent SnO2 dispersion added in step S2 is 0.5~2vol%.

[0013] 3. The method for preparing an electron transport layer according to claim 1, wherein the pH of the dispersion in step S2 is adjusted to 3-5.

[0014] Furthermore, the modification reaction temperature in step S2 is 75-95° C., and the reaction time is 1-3 h.

[0015] Furthermore, the mass ratio of SnO2@APTMS nanoparticles to graphene oxide in step S1 is (95~99): (0.5~5).

[0016] The present invention also provides a perovskite solar cell, comprising the electron transport layer as described above, wherein the cell structure from bottom to top is an ITO substrate, an electron transport layer, a perovskite layer, and a carbon electrode, wherein the electron transport layer is SnO2@APTMS:GO; the perovskite layer material is CH3NH3PbI3, and is formed by spin coating a perovskite solution on the electron transport layer and then annealing; the carbon electrode is formed on the perovskite layer by a doctor blade method and then annealing.

[0017] Furthermore, the annealing temperature during the preparation of the electron transport layer, the perovskite layer and the carbon electrode is 140-160° C., and the annealing time is 25-35 minutes.

[0018] Furthermore, the thickness of the SnO2@APTMS:GO electron transport layer is 15-25 nm, and the thickness of the perovskite layer is 250-300 nm.

[0019] The present invention also provides a SnO2@APTMS:GO composite material, which is prepared by the above-mentioned method for preparing an electron transport layer, wherein the siloxane coupling agent APTMS undergoes a condensation reaction with the surface hydroxyl groups of SnO2 to form Si-O-Si and / or Si-O-Sn covalent bonds to obtain SnO2@APTMS nanoparticles; the SnO2@APTMS nanoparticles are compounded with graphene oxide through π-π conjugation to obtain the SnO2@APTMS:GO composite material.

[0020] The beneficial effects produced by the technical solution of the present invention are as follows:

[0021] (1) The present invention uses a siloxane coupling agent (3-aminopropyltrimethoxysilane (APTMS)) to modify SnO2 nanoparticles to obtain alkyl-functionalized end-capped SnO2 nanoparticles (SnO2@APTMS). After hydrolysis, the siloxane condenses with the hydroxyl groups on the SnO2 surface to form stable Si-O-Si or Si-O-Sn bonds. Due to the reduction of hydroxyl groups on the SnO2 surface, the SnO2@APTMS nanoparticles have better dispersibility. The number of oxygen defects adsorbed on the SnO2 surface is also greatly reduced, reducing surface defects and improving charge transfer efficiency. In addition, a small amount of graphene oxide (GO) is doped into the SnO2@APTMS nanoparticle solution to obtain a SnO2@APTMS:GO electron transport layer, which further improves the conductivity of SnO2 and the performance of PSCs devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 is a SEM image of the electron transport layer in Example 1 of the present invention;

[0024] Figure 2 is an SEM image of the perovskite layer in Example 1 of the present invention;

[0025] Figure 3 is a SEM image of the electron transport layer in Comparative Example 1 of the present invention;

[0026] Figure 4 is an SEM image of the perovskite layer in Comparative Example 1 of the present invention;

[0027] Figure 5 This is a UPS test diagram of different interface layers of the perovskite solar cell of the present invention;

[0028] Figure 6 is the energy level diagram of the perovskite solar cell of the present invention;

[0029] Figure 7 is a graph showing the relationship between the normalized PCE of the perovskite solar cell of the present invention and aging time (40% RH air); DETAILED DESCRIPTION

[0030] 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 in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] This embodiment uses a siloxane coupling agent to modify SnO2 nanoparticles to obtain alkyl-functionalized SnO2 nanoparticles. A small amount of graphene oxide (GO) is doped into the SnO2@APTMS nanoparticle solution to obtain a SnO2@APTMS:GO electron transport layer, further improving the conductivity of SnO2 and the performance of PSCs devices, thereby overcoming the problems of carrier recombination loss and interface instability caused by SnO2 interface defects. The specific implementation is as follows:

[0032] A method for preparing a SnO2@APTMS electron transport layer for a perovskite solar cell comprises the following steps:

[0033] S1, dispersing SnO2 nanopowder in anhydrous ethanol and forming a SnO2 dispersion after ultrasonic treatment;

[0034] S2. Adjust the pH of the dispersion to an acidic condition and add siloxane coupling agent 3-aminopropyltrimethoxysilane (APTMS) to carry out modification reaction;

[0035] S3, centrifugation and washing to remove unreacted products, followed by vacuum drying to obtain SnO2@APTMS nanoparticle powder;

[0036] S4, dispersing SnO2@APTMS nanoparticles and graphene oxide in anhydrous ethanol, and forming SnO2@APTMS:GO nanoparticle dispersion by ultrasonic treatment;

[0037] S5. Spin-coat the SnO2@APTMS:GO nanoparticle dispersion on the substrate and anneal to form a SnO2@APTMS:GO electron transport layer.

[0038] Here, SnO2 nanoparticles were modified with a siloxane coupling agent (APTMS) to obtain SnO2@APTMS with improved dispersibility and conductivity. While maintaining the properties of the SnO2@APTMS nanoparticles, the conductivity of SnO2 was further enhanced by doping with GO to form a SnO2@APTMS:GO electron transport layer. The appropriate amount of GO doping fills the gaps between the SnO2@APTMS nanoparticles, forming a more continuous conductive network and thus improving the conductivity of the electron transport layer. This method effectively reduces defects such as oxygen vacancies, surface hydroxyl groups, and unsaturated dangling bonds on the SnO2 surface, improving charge transfer efficiency and significantly enhancing the photoelectric conversion efficiency and stability of perovskite solar cells.

[0039] As a preferred embodiment, the amount of the siloxane coupling agent SnO2 dispersion added in step S2 is 0.5-2 vol%.

[0040] As a preferred embodiment, the pH of the SnO2 dispersion in step S2 is adjusted to 3-5.

[0041] As a preferred embodiment, the modification reaction temperature in step S2 is 75-95° C. and the reaction time is 1-3 h.

[0042] As a preferred embodiment, the mass ratio of SnO2@APTMS nanoparticles to graphene oxide in step S4 is (95~99): (0.5~5).

[0043] The present invention also provides a perovskite solar cell, comprising the electron transport layer as described above, wherein the cell structure from bottom to top comprises an ITO substrate, an electron transport layer, a perovskite layer, and a carbon electrode, wherein:

[0044] The electron transport layer is SnO2@APTMS:GO;

[0045] The perovskite layer material is CH3NH3PbI3, which is formed by spin coating a perovskite solution on the electron transport layer and then annealing;

[0046] The carbon electrode is formed on the perovskite layer by a doctor blade coating method and then subjected to an annealing treatment.

[0047] Here, the electron transport layer is composed of SnO2@APTMS:GO. This structural design aims to improve the photoelectric conversion efficiency and stability of the battery by using the SnO2@APTMS:GO electron transport layer. Compared with the unmodified SnO2 electron transport layer, it can significantly reduce interfacial defects and improve charge transfer efficiency, thereby improving the overall performance of the battery.

[0048] Furthermore, the annealing temperature during the preparation of the electron transport layer, the perovskite layer and the carbon electrode is 140-160° C., and the annealing time is 25-35 minutes.

[0049] Annealing is a crucial step in the preparation of the electron transport layer. It helps remove solvent, promotes the crystallization and alignment of nanoparticles, removes residual solvent, and enhances interparticle contact, ultimately resulting in a stable electron transport layer. Proper annealing temperature and time prevent high-temperature damage to the substrate, ensuring the electron transport layer maintains optimal morphology and performance.

[0050] As a preferred embodiment, the thickness of the SnO2@APTMS:GO electron transport layer is 15-25 nm, and the thickness of the perovskite layer is 250-300 nm.

[0051] Here, while maintaining battery performance, the manufacturing cost is reduced. The appropriate thickness of the electron transport layer can ensure good charge transport performance, while the appropriate thickness of the perovskite layer can optimize the balance between light absorption and carrier diffusion length to ensure sufficient light absorption and charge generation.

[0052] This embodiment also provides a SnO2@APTMS:GO composite material, which is prepared by the preparation method of the electron transport layer as described above, wherein the siloxane coupling agent APTMS undergoes a condensation reaction with the hydroxyl groups on the surface of SnO2 to form Si-O-Si and / or Si-O-Sn covalent bonds to obtain SnO2@APTMS nanoparticles; the SnO2@APTMS nanoparticles are compounded with graphene oxide through π-π conjugation to obtain the SnO2@APTMS:GO composite material.

[0053] Here, the condensation reaction between the siloxane coupling agent APTMS and the hydroxyl groups on the SnO2 surface forms stable Si-O-Si and / or Si-O-Sn covalent bonds, providing amino active sites for anchoring GO. Through π-π conjugation, the SnO2@APTMS nanoparticles and GO are composited, further improving the conductivity and battery performance of SnO2. This structural feature effectively reduces defects on the SnO2 surface, improves the dispersion and stability of SnO2, and thus helps to enhance the performance of perovskite solar cells.

[0054] Example 1

[0055] A perovskite solar cell containing a SnO2@APTMS:GO electron transport layer was prepared, which has the following device structure: ITO (100nm) / electron transport layer (ETL) (20nm) / perovskite layer (PVSK) (280nm) / carbon electrode (30μm). The specific preparation steps are as follows:

[0056] 1) The specific preparation steps of the electron transport layer are as follows:

[0057] S1. Disperse nano-SnO2 powder in anhydrous ethanol and ultrasonicate for 0.5 h to form a uniform dispersion;

[0058] S2. Add dilute hydrochloric acid to adjust the pH to 4, then add 1 vol% of siloxane coupling agent relative to the SnO2 dispersion, and react at 85°C for 2 hours;

[0059] S3, centrifugation to remove the supernatant, the supernatant was washed with anhydrous ethanol and deionized water for several times to completely remove the unreacted siloxane coupling agent until the waste liquid was neutral, and the obtained solid was vacuum dried to obtain alkyl-functionalized nanoparticle powder SnO2@APTMS;

[0060] S4, dispersing SnO2@APTMS nanoparticle powder and graphene oxide in anhydrous ethanol at a mass ratio of 95:4, and ultrasonically treating for 1 h to form a uniform SnO2@APTMS:GO nanoparticle dispersion;

[0061] S5. Spin-coat a certain amount of the SnO2@APTMS:GO nanoparticle solution on the ITO substrate and anneal to obtain an electron transport layer. The annealing temperature is 150° C. and the annealing time is 30 min.

[0062] 2) Preparation of perovskite solar cells:

[0063] S1. Spin-coating a certain amount of perovskite solution on the prepared electron transport layer and annealing the solution to obtain a perovskite layer. The annealing temperature is 150° C. and the annealing time is 30 min.

[0064] S2, applying the carbon slurry on the perovskite layer and annealing the layer to obtain a perovskite solar cell containing SnO2@APTMS:GO, wherein the annealing temperature is 150°C and the annealing time is 30 minutes;

[0065] S3. Annealing the carbon electrode on the perovskite layer by a doctor blade method at an annealing temperature of 150° C. for 30 minutes.

[0066] Example 2

[0067] A perovskite solar cell containing a SnO2@APTMS:GO electron transport layer was prepared, which has the following device structure: ITO (100nm) / electron transport layer (ETL) (20nm) / perovskite layer (PVSK) (280nm) / carbon electrode (30μm). The specific preparation steps are as follows:

[0068] 1) The specific preparation steps of the electron transport layer are as follows:

[0069] S1. Disperse nano-SnO2 powder in anhydrous ethanol and ultrasonicate for 0.5 h to form a uniform dispersion;

[0070] S2. Add dilute hydrochloric acid to adjust the pH to 4, then add 1.5 vol% of siloxane coupling agent relative to the SnO2 dispersion, and react at 85°C for 2 hours;

[0071] S3, centrifugation to remove the supernatant, the supernatant was washed with anhydrous ethanol and deionized water for several times to completely remove the unreacted siloxane coupling agent until the waste liquid was neutral, and the obtained solid was vacuum dried to obtain alkyl-functionalized nanoparticle powder SnO2@APTMS;

[0072] S4, dispersing SnO2@APTMS nanoparticle powder and graphene oxide in anhydrous ethanol at a mass ratio of 99:5, and ultrasonically treating for 1 h to form a uniform SnO2@APTMS:GO nanoparticle dispersion;

[0073] S5. Spin-coat a certain amount of the SnO2@APTMS:GO nanoparticle solution on the ITO substrate and anneal to obtain an electron transport layer. The annealing temperature is 145° C. and the annealing time is 35 min.

[0074] 2) Preparation of perovskite solar cells:

[0075] S1. Spin-coating a certain amount of perovskite solution on the prepared electron transport layer and annealing the solution to obtain a perovskite layer. The annealing temperature is 145° C. and the annealing time is 35 min.

[0076] S2, then applying the carbon slurry on the perovskite layer and annealing to obtain a perovskite solar cell containing SnO2@APTMS:GO, wherein the annealing temperature is 145°C and the annealing time is 35 minutes;

[0077] S3. Annealing the carbon electrode on the perovskite layer by a doctor blade method, wherein the annealing temperature is 145° C. and the annealing time is 35 minutes.

[0078] Example 3

[0079] A perovskite solar cell containing a SnO2@APTMS:GO electron transport layer was prepared, which has the following device structure: ITO (100nm) / electron transport layer (ETL) (20nm) / perovskite layer (PVSK) (280nm) / carbon electrode (30μm). The specific preparation steps are as follows:

[0080] 1) The specific preparation steps of the electron transport layer are as follows:

[0081] S1. Disperse nano-SnO2 powder in anhydrous ethanol and ultrasonicate for 0.5 h to form a uniform dispersion;

[0082] S2, adding dilute hydrochloric acid to adjust the pH value to 4, then adding 2 vol% of siloxane coupling agent relative to the SnO2 dispersion, and reacting at 85 ° C for 2 hours;

[0083] S3, centrifugation to remove the supernatant, the supernatant was washed with anhydrous ethanol and deionized water for several times to completely remove the unreacted siloxane coupling agent until the waste liquid was neutral, and the obtained solid was vacuum dried to obtain nanoparticle powder SnO2@APTMS;

[0084] S4, dispersing SnO2@APTMS nanoparticle powder and graphene oxide in anhydrous ethanol at a mass ratio of 96:4, and ultrasonically treating for 0.5 h to form a uniform SnO2@APTMS:GO nanoparticle dispersion;

[0085] S5. Take a certain amount of the SnO2@APTMS:GO nanoparticle solution and spin-coat it on the substrate.

[0086] On ITO, and annealing is performed to obtain an electron transport layer; the annealing temperature is 160° C., and the annealing time is 25 minutes;

[0087] 2) Preparation of perovskite solar cells:

[0088] S1. Spin-coat a certain amount of perovskite solution on the prepared electron transport layer and anneal to obtain a perovskite layer. The annealing temperature is 160° C. and the annealing time is 25 min.

[0089] S2, then applying the carbon slurry on the perovskite layer and annealing it to obtain a perovskite solar cell containing SnO2@APTMS:GO. The annealing temperature is 160°C and the annealing time is 25 min.

[0090] S3. Annealing the carbon electrode on the perovskite layer by a doctor blade method at an annealing temperature of 160° C. for 25 minutes.

[0091] Example 4

[0092] A perovskite solar cell containing a SnO2@APTMS:GO electron transport layer was prepared, which has the following device structure: ITO (100nm) / electron transport layer (ETL) (20nm) / perovskite layer (PVSK) (280nm) / carbon electrode (30μm). The specific preparation steps are as follows:

[0093] 1) The specific preparation steps of the electron transport layer are as follows:

[0094] S1. Disperse nano-SnO2 powder in anhydrous ethanol and ultrasonicate for 0.5 h to form a uniform dispersion;

[0095] S2. Add dilute hydrochloric acid to adjust the pH to 4, then add 1 vol% of siloxane coupling agent relative to the SnO2 dispersion, and react at 85°C for 2 hours;

[0096] S3, centrifugation to remove the supernatant, the supernatant was washed with anhydrous ethanol and deionized water for several times to completely remove the unreacted siloxane coupling agent until the waste liquid was neutral, and the obtained solid was vacuum dried to obtain nanoparticle powder SnO2@APTMS;

[0097] S4, dispersing SnO2@APTMS nanoparticle powder and graphene oxide in anhydrous ethanol at a mass ratio of 95:4, and ultrasonically treating for 1 h to form a uniform SnO2@APTMS:GO nanoparticle dispersion;

[0098] S5. Spin-coat a certain amount of the SnO2@APTMS:GO nanoparticle solution on a substrate (ITO) and anneal to obtain an electron transport layer. The annealing temperature is 150° C. and the annealing time is 30 min.

[0099] 2) Preparation of perovskite solar cells:

[0100] S1. Spin-coat a certain amount of perovskite solution on the prepared electron transport layer and anneal to obtain a perovskite layer. The annealing temperature is 150° C. and the annealing time is 30 min.

[0101] S2, then applying the carbon slurry on the perovskite layer and annealing it to obtain a perovskite solar cell containing SnO2@APTMS:GO, the annealing temperature is 150°C, and the annealing time is 30 min;

[0102] S3. Annealing the carbon electrode on the perovskite layer by a doctor blade method at an annealing temperature of 150° C. for 30 minutes.

[0103] Comparative Example 1

[0104] A perovskite solar cell containing a SnO2 electron transport layer is prepared, which has the following device structure: ITO (100nm) / electron transport layer (ETL) (20nm) / perovskite layer (PVSK) (280nm) / carbon electrode (30μm). The specific preparation steps are as follows:

[0105] 1) The specific preparation steps of the electron transport layer are as follows:

[0106] S1. Disperse nano-SnO2 powder in anhydrous ethanol and ultrasonicate for 1 h to form a uniform dispersion;

[0107] S2, taking a certain amount of the SnO2 nanoparticle solution and spin-coating it on the ITO substrate, and annealing it to obtain an electron transport layer; the annealing temperature is 150° C., and the annealing time is 30 minutes;

[0108] 2) Preparation of perovskite solar cells:

[0109] S1. Spin-coating a certain amount of perovskite solution on the electron transport layer and annealing to obtain a perovskite layer; the annealing temperature is 150° C. and the annealing time is 30 min;

[0110] S2. Then, the carbon slurry is scraped onto the perovskite layer and annealed to obtain a perovskite solar cell containing SnO2; the annealing temperature is 150°C and the annealing time is 30 minutes.

[0111] S3. Annealing the carbon electrode on the perovskite layer by a doctor blade method at an annealing temperature of 150° C. for 30 minutes.

[0112] Comparative Example 2

[0113] A perovskite solar cell containing a SnO2@APTMS electron transport layer is prepared, which has the following device structure: ITO (100nm) / electron transport layer (ETL) (20nm) / perovskite layer (PVSK) (280nm) / carbon electrode (30μm). The specific preparation steps are as follows:

[0114] 1) The specific preparation steps of the electron transport layer are as follows:

[0115] S1. Disperse nano-SnO2 powder in anhydrous ethanol and ultrasonicate for 0.5h to form

[0116] Uniform dispersion;

[0117] S2. Add dilute hydrochloric acid to adjust the pH to 4, then add the relative SnO2 dispersion

[0118] 0.5 vol% siloxane coupling agent, reaction at 85 ° C for 2 h;

[0119] S3, centrifugation, removing the supernatant, washing the supernatant with anhydrous ethanol and deionized water for multiple times to completely remove the unreacted siloxane coupling agent until the waste liquid is neutral, and vacuum drying the obtained solid to obtain nanoparticle powder SnO2@APTMS;

[0120] S4, dispersing the SnO2@APTMS nanoparticle powder in anhydrous ethanol and ultrasonically treating for 1 h to form a uniform SnO2@APTMS nanoparticle dispersion;

[0121] S5, taking a certain amount of the SnO2@APTMS nanoparticle solution and spin-coating it on the ITO substrate, and annealing it to obtain an electron transport layer, wherein the annealing temperature is 150° C. and the annealing time is 30 min;

[0122] 2) Preparation of perovskite solar cells:

[0123] S1. Spin-coating a certain amount of perovskite solution on the prepared electron transport layer and annealing the solution to obtain a perovskite layer. The annealing temperature is 150° C. and the annealing time is 30 min.

[0124] S2, then applying the carbon slurry on the perovskite layer and annealing it to obtain a perovskite solar cell containing SnO2@APTMS, the annealing temperature being 150°C and the annealing time being 30 min;

[0125] S3. Annealing the carbon electrode on the perovskite layer by a doctor blade method at an annealing temperature of 150° C. for 30 minutes.

[0126] The performance of the perovskite solar cells prepared in the above-mentioned groups 1 to 5 of Examples and 1 of Comparative Example is tested. The test data are shown in Table 1:

[0127] Table 1: Performance data of perovskite solar cells in examples and comparative examples

[0128] Group Open circuit voltage Voc(V) Short-circuit current Isc(mA) Fill factor FF(%) Efficiency PCE(%) Example 1 1.00 16.27 64.05 10.42 Example 2 0.98 15.73 62.91 10.03 Example 3 0.99 16.69 64.03 10.58 Example 4 1.00 16.89 64.22 10.85 Comparative Example 1 0.98 15.49 63.70 9.67 Comparative Example 2 0.99 15.96 63.45 9.52

[0129] As shown in Table 1, the perovskite solar cells prepared in the Examples of the present invention, with SnO2@APTMS and SnO2@APTMS:GO as the transport layer, exhibit higher efficiency compared to the comparative perovskite solar cells. Compared to cells with unmodified SnO2 electron transport layers, the cells using the SnO2@APTMS:GO electron transport layer increased the photoelectric conversion efficiency by over 10%. This significant improvement demonstrates the effectiveness of the present invention in improving the performance of perovskite solar cells.

[0130] Reference Figure 1-4As shown in the figure, SnO2@APTMS has better dispersibility and fewer surface defects than SnO2, and has a better passivation effect on the perovskite layer. Therefore, the SnO2@APTMS / perovskite layer has a larger grain size, a smoother surface, and a better morphology than the SnO2 / perovskite layer.

[0131] Reference Figure 5-6 As shown in the figure, the work functions of ITO modified with SnO2@APTMS and SnO2@APTMS:GO are -4.16eV and -4.12eV, respectively, which are lower than the work function of ITO modified with simple SnO2, and have better energy level matching with the perovskite layer.

[0132] Reference Figure 7 As shown in the figure, the perovskite cells based on SnO2@APTMS and SnO2@APTMS:GO have better stability than the perovskite cells based on SnO2 alone.

[0133] The present invention is further described above with the aid of specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the essence and scope of the present invention. Various modifications made to the above embodiments by ordinary technicians in this field after reading this specification are all within the scope of protection of the present invention.

Claims

1. A method for preparing an electron transport layer for a perovskite solar cell, characterized in that: The following steps are involved: S1, dispersing SnO2 nanopowder in anhydrous ethanol and forming a SnO2 dispersion after ultrasonic treatment; S2. Adjust the pH of the dispersion to an acidic condition and add siloxane coupling agent 3-aminopropyltrimethoxysilane (APTMS) to carry out modification reaction; S3, centrifugation and washing to remove unreacted products, followed by vacuum drying to obtain SnO2@APTMS nanoparticle powder; S4, dispersing SnO2@APTMS nanoparticles and graphene oxide in anhydrous ethanol, and forming SnO2@APTMS:GO nanoparticle dispersion by ultrasonic treatment; S5. Spin-coat the SnO2@APTMS:GO nanoparticle dispersion on the substrate and anneal to form a SnO2@APTMS:GO electron transport layer.

2. The method for preparing an electron transport layer according to claim 1, wherein: The amount of the siloxane coupling agent added to the SnO2 dispersion in step S2 is 0.5-2 vol%.

3. The method for preparing an electron transport layer according to claim 1, wherein: The pH of the dispersion in step S2 is adjusted to 3-5.

4. The method for preparing an electron transport layer according to claim 1, wherein: The modification reaction temperature in step S2 is 75-95° C., and the reaction time is 1-3 h.

5. The method for preparing an electron transport layer according to claim 1, wherein: The mass ratio of SnO2@APTMS nanoparticles to graphene oxide in step S1 is (95~99): (0.5~5).

6. A perovskite solar cell, characterized in that: The battery comprises the electron transport layer according to any one of claims 1 to 3, wherein the battery structure comprises an ITO substrate, an electron transport layer, a perovskite layer, and a carbon electrode from bottom to top, wherein: The electron transport layer is SnO2@APTMS:GO; The perovskite layer material is CH3NH3PbI3, which is formed by spin coating a perovskite solution on the electron transport layer and then annealing; The carbon electrode is formed on the perovskite layer by a doctor blade coating method and then subjected to an annealing treatment.

7. The perovskite solar cell according to claim 6, characterized in that The annealing temperature during the preparation of the electron transport layer, the perovskite layer and the carbon electrode is 140-160° C., and the annealing time is 25-35 minutes.

8. The perovskite solar cell according to claim 6, characterized in that The thickness of the SnO2@APTMS:GO electron transport layer is 15-25 nm, and the thickness of the perovskite layer is 250-300 nm.

9. A SnO2@APTMS:GO composite material, characterized in that The method for preparing an electron transport layer according to any one of claims 1 to 5 is used, wherein the siloxane coupling agent APTMS undergoes a condensation reaction with the surface hydroxyl groups of SnO2 to form Si-O-Si and / or Si-O-Sn covalent bonds to obtain SnO2@APTMS nanoparticles; and the SnO2@APTMS nanoparticles are compounded with graphene oxide through π-π conjugation to obtain a SnO2@APTMS:GO composite material.

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