Low-temperature preparation method of perovskite back electrode based on chemical coupling agent

Abstract

The invention discloses a low-temperature preparation method of a perovskite back electrode based on a chemical coupling agent, and particularly relates to the technical field of perovskite solar cells, and the method comprises the following steps: 1, carrying out the surface functionalization of perovskite, coating a chemical coupling agent solution on a surface slit, carrying out the annealing, forming a compact coupling layer, and enhancing the chemical bonding of subsequent ITO; step 2, constructing an ITO-Cu conductive network, and constructing an ITO-Cu vertical conductive network with the thickness of 80-100 nm by adopting a magnetron sputtering method; and step 3, forming an ITO ultrathin hydrophobic layer of 10-20 nm on the original conductive network by adopting magnetron sputtering to prevent oxidation of the ITO-Cu conductive network and improve the mechanical strength. The efficiency of the perovskite assembly of the electrode is improved from 17.74% to 19.54%, in order to verify the operation stability, MPP tracking is carried out under continuous illumination at 30 DEG C, the efficiency of the optimized assembly can still be kept to be larger than 90% after 1000 h, and tests show that the sheet resistance of the composite electrode is about 400 m omega / sq, and the interface bonding force (stripping test) is improved by about 20%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of perovskite solar cells, and more particularly to a low-temperature preparation method of a perovskite back electrode based on a chemical coupling agent. BACKGROUND

[0002] The back electrode of a perovskite solar cell is a key component that affects the efficiency and stability of the device. Traditional back electrodes mostly use single metals (such as Au, Ag), transparent conductive oxides (TCO), or carbon-based materials, which have the following problems: 1. Interface metal corrosion: ion migration (such as Ag + diffusion) easily occurs between the metal electrode and the perovskite layer, leading to interface peeling and device failure; 2. Insufficient conductivity: carbon-based electrodes or TCO electrodes have high resistance and poor adhesion; 3. Poor environmental stability: water and oxygen corrosion in a humid and hot environment easily leads to electrode corrosion, reducing the service life of the device; 4. Weak interface: nanowires and the substrate are only physically adsorbed, which is easy to peel off. In recent years, research has attempted to use graphene or metal nanowires alone as an electrode, but graphene has high contact resistance and poor adhesion, and metal nanowires are prone to aggregation and oxidation.

[0003] In a transverse perovskite solar cell, tin oxide (SnO2) is usually used as a buffer layer. Although SnO2 has high electron mobility and suitable energy level matching, the interface between SnO2 and the ITO electrode usually has poor adhesion, which can lead to delamination of the device during long-term operation or under thermal cycling and mechanical stress, thereby severely affecting its long-term stability. In the prior art, back electrode improvements mostly focus on single-layer or double-layer modification (such as an interface passivation layer or a conductive composite), but it is difficult to simultaneously solve the problems of chemical bonding, conductivity, and protection.

[0004] Therefore, there is an urgent need for a low-temperature preparation method of a perovskite back electrode based on a chemical coupling agent to solve the above problems. SUMMARY

[0005] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present application provide a low-temperature preparation method of a perovskite back electrode based on a chemical coupling agent to solve the problems raised in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a low-temperature preparation method of a perovskite back electrode based on a chemical coupling agent, comprising the following steps: Step one: perovskite surface functionalization, coating a chemical coupling agent solution in the surface slit, annealing to form a dense coupling layer, and enhancing the chemical bonding of the subsequent ITO; Step two: ITO-Cu conductive network construction, using a magnetron sputtering method to construct an 80-100 nm thick ITO-Cu vertical conductive network; Step three: on the original conductive network, a 10-20 nm ITO ultra-thin hydrophobic layer is formed by magnetron sputtering to prevent the ITO-Cu conductive network from being oxidized and to improve the mechanical strength; Step four: a back electrode composed of three functional layers of a chemical coupling agent coating layer from top to bottom, an ITO / Cu mixed conductive layer, and an ITO transparent conductive protective layer is obtained.

[0007] In a preferred embodiment, the chemical coupling agent solution in step one is set as isopropanol.

[0008] In a preferred embodiment, the isopropanol concentration is set to 3-5 wt%.

[0009] In a preferred embodiment, the annealing temperature in step one is 80-120 ℃.

[0010] In a preferred embodiment, the annealing time in step one is 5 min.

[0011] Technical effects and advantages of the present application: The present application first functionalizes the perovskite surface, applies a chemical coupling agent solution to the surface slit, and forms a dense coupling layer by annealing to enhance the chemical bonding of subsequent ITO. An ITO-Cu conductive network is constructed, and a 80-100 nm thick ITO-Cu vertical conductive network is constructed by magnetron sputtering. On the original conductive network, a 10-20 nm ITO ultra-thin hydrophobic layer is formed by magnetron sputtering to prevent the ITO-Cu conductive network from being oxidized and to improve the mechanical strength. A back electrode composed of three functional layers of a chemical coupling agent coating layer from top to bottom, an ITO / Cu mixed conductive layer, and an ITO transparent conductive protective layer is obtained. Compared with the traditional evaporation Cu electrode, the efficiency of the perovskite module of the electrode of the present application is increased from 17.74% to 19.54%. In order to verify the operation stability, the maximum power point (MPP) tracking is performed under continuous illumination at 30 °C, and the efficiency of the optimized module can still maintain >90% after 1000 h. The composite electrode sheet resistance is about 400 mΩ / sq, and the interfacial bonding force (peeling test) is increased by about 20%. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 The efficiency of the perovskite solar module based on different electrodes of the present application is shown.

[0013] Figure 2 The perovskite solar module of the present application Figure 1 The maximum power point (MPP) tracking test schematic diagram of the perovskite solar module in the present application under continuous illumination at 30 °C.

[0014] Figure 3This is a schematic diagram of the test results for the conductivity of the electrodes in the four-probe sheet resistance meter of the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] As attached Figure 1 Appendix Figure 2 and attached Figure 3 As shown, this invention provides a low-temperature preparation method for a perovskite back electrode based on a chemical coupling agent, comprising the following steps: Step 1: Perovskite surface functionalization: a chemical coupling agent solution is coated on the surface slits, and annealing is performed to form a dense coupling layer, which enhances the subsequent chemical bonding of ITO. Step 2: Construction of ITO-Cu conductive network. An 80-100 nm thick ITO-Cu vertical conductive network was constructed using magnetron sputtering. Step 3: On the existing conductive network, a 10-20 nm ultrathin hydrophobic layer of ITO is formed by magnetron sputtering to prevent oxidation of the ITO-Cu conductive network and improve mechanical strength; Step 4: Obtain the back electrode, which consists of three functional layers from top to bottom: a chemical coupling agent coating layer, an ITO / Cu mixed conductive layer, and an ITO transparent conductive protective layer.

[0017] The chemical coupling agent solution in step one is isopropanol.

[0018] The isopropanol concentration was set to 3-5 wt%.

[0019] The annealing temperature in step one is 80-120 ℃.

[0020] The annealing time in step one is 5 minutes.

[0021] Comparative Example 1 Perovskite solar cell modules using conventionally vapor-deposited Cu as the back electrode Standard preparation of 10×10 cm 2 The perovskite solar cell module (pin structure) is then tested. The specific steps are as follows: 1. Preparation of hole transport layer thin films a. Prepare solar cell substrate: Etch patterns on the transparent conductive glass substrate (ITO / glass) using a laser. After etching, clean it in sequence with cleaning solution, deionized water, ethanol, and isopropanol, and then dry it for later use.

[0022] b. Using magnetron sputtering, NiOx was sputtered onto the etched conductive substrate. The sputtering conditions were: Ni planar palladium, DC power supply 200W, 25min, carrier gas flow rate Ar:O2=200:20 (sccm). After sputtering, the substrate was annealed at 300 °C for 30min.

[0023] 2. Set up a perovskite light-absorbing layer PbI₂, CH(NH₂)₂I, PbBr₂, and NH₃CH₃Br were dissolved in a DMF:NMP mixture of 1.1:1:0.22:0.2 (volume ratio) to obtain the absorber layer precursor solution. The perovskite solution was coated onto a substrate with a hole transport layer using a slit coating method, as follows: pre-injection volume 40 μl, pre-injection rate 9 μl / s, coating speed 5 cm / s, injection rate 1.75 μl / s, and waiting time 2 s. Immediately after coating, the substrate was transferred to a vacuum crystallization apparatus and crystallized at 20 kPa for 1 min. After removal, the substrate was treated at 150 °C for 10 min to obtain the perovskite thin film.

[0024] 3. Set up an electronic transport layer C60 was deposited onto the thin film prepared above by vacuum thermal evaporation, with a thickness of 20 nm.

[0025] 4. Set up a SnO2 buffer layer SnO2 was prepared on the above-mentioned thin film with a thickness of approximately 20 nm using atomic layer deposition (ALD) technology.

[0026] 5. Set the back electrode layer A complete cell was obtained by vacuum thermal evaporation of a 100 nm pure Cu electrode onto a structure with a SnO2 buffer layer.

[0027] Example 1 Perovskite solar cell modules with composite structures to enhance the back electrode 1. As described in the comparative example, perovskite solar cell modules are conventionally prepared up to step 4: the SnO2 buffer layer is completed; 2. The ITO conductive layer was prepared by magnetron sputtering. The sputtering conditions were: ITO planar palladium, RF power supply 0.9kW, 15min, carrier gas flow rate Ar:O2 = 299.4:0.8 sccm. The background vacuum was ≤5×10-4 Pa, and the working gas pressure was approximately 0.4 Pa.

[0028] 3. Cu conductive layer was prepared on ITO substrate by magnetron sputtering. Sputtering conditions: Cu rotating target, direct current power 1.8 kW, 5 min, carrier gas flow Ar = 800 sccm. Base vacuum ≤ 5 x 10-4 Pa, working pressure about 0.4 Pa.

[0029] 4. The protective layer was prepared by magnetron sputtering. Sputtering conditions: ITO rotating target, direct current power 2.7 kW, 5 min, carrier gas flow Ar = 406.7:3.3 sccm. Base vacuum ≤ 5 x 10-4 Pa, working pressure about 0.4 Pa.

[0030] Example 2 Perovskite solar module with chemical coupling agent and composite structure back electrode 1. The method as described in Comparative Example, conventional preparation of perovskite solar module to step 4: Sn02 buffer layer preparation is completed; 2. Spin coating 3% wt% of 1,4-benzenedi phosphonic acid in isopropanol solution (chemical coupling agent) on the surface of Sn02, pre-injection volume 40 μΐ, pre-injection speed 9 μΐ / s, coating speed 5 cm / s, injection speed 1.75 μΐ / s, waiting time 2 s. After coating, immediately anneal at high temperature annealing table 100 °C for 5 min to form a monolayer.

[0031] 3. As described in steps 1-4 of Example 1, prepare a composite structure back electrode with ITO-Cu conductive network and ITO protective layer.

[0032] Compared with the conventional evaporation Cu electrode, the efficiency of the perovskite module of the electrode of the present application is improved from 17.74% to 19.54%, and in order to verify the operation stability, the maximum power point (MPP) tracking is carried out under continuous illumination at 30 °C, and the efficiency of the optimized module can still maintain > 90% after 1000 h. After testing, the composite electrode sheet resistance is about 400 mΩ / sq, and the interface bonding force (peeling test) is improved by about 20%.

[0033] The application firstly functionalizes perovskite surface, coats a chemical coupling agent solution in a surface slit, anneals to form a dense coupling layer, enhances the chemical bonding of subsequent ITO, constructs an ITO-Cu conductive network, adopts a magnetron sputtering method to construct an 80-100 nm thick ITO-Cu vertical conductive network, adopts magnetron sputtering to form a 10-20 nm ITO ultrathin hydrophobic layer on the original conductive network, prevents the ITO-Cu conductive network from being oxidized and improves the mechanical strength, obtains a back electrode composed of three functional layers of a top-down chemical coupling agent coating layer, an ITO / Cu mixed conductive layer and an ITO transparent conductive protective layer, compared with a traditional evaporated Cu electrode, the efficiency of the perovskite module of the electrode is increased from 17.74% to 19.54%, and in order to verify the operation stability, the maximum power point (MPP) tracking is carried out under continuous illumination at 30 DEG C, the efficiency of the optimized module can still be kept > 90% after 1000 h, and the test shows that the composite electrode sheet resistance is about 400 m Omega / sq, and the interface bonding force (peeling test) is increased by about 20%.

[0034] Finally: the above only describes the preferred embodiments of the application and is not used to limit the application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A low-temperature preparation method for a perovskite back electrode based on a chemical coupling agent, characterized in that, Includes the following steps: Step 1: Perovskite surface functionalization: a chemical coupling agent solution is coated on the surface slits, and annealing is performed to form a dense coupling layer, which enhances the subsequent chemical bonding of ITO. Step 2: Construction of ITO-Cu conductive network. An 80-100 nm thick ITO-Cu vertical conductive network was constructed using magnetron sputtering. Step 3: On the existing conductive network, a 10-20 nm ultrathin hydrophobic layer of ITO is formed by magnetron sputtering; Step 4: Obtain the back electrode, which consists of three functional layers from top to bottom: a chemical coupling agent coating layer, an ITO / Cu mixed conductive layer, and an ITO transparent conductive protective layer.

2. The low-temperature preparation method of a perovskite back electrode based on a chemical coupling agent according to claim 1, characterized in that: The chemical coupling agent solution in step one is isopropanol.

3. The low-temperature preparation method of a perovskite back electrode based on a chemical coupling agent according to claim 1, characterized in that: The isopropanol concentration was set to 3-5 wt%.

4. The low-temperature preparation method of a perovskite back electrode based on a chemical coupling agent according to claim 1, characterized in that: The annealing temperature in step one is 80-120 ℃.

5. The low-temperature preparation method of a perovskite back electrode based on a chemical coupling agent according to claim 1, characterized in that: The annealing time in step one is 5 minutes.

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