Preparation method of normal-temperature ITO thin film and application of normal-temperature ITO thin film in perovskite battery

Abstract

A preparation method of a normal-temperature ITO film comprises the steps that a battery intermediate to be coated is placed in magnetron sputtering equipment, the sputtering power of the magnetron sputtering equipment is set to be 100 W to 300 W, the pressure intensity of a cavity is set to be 0.1 Pa to 1 Pa, an ITO ceramic target is adopted as a sputtering source, sputtering gas is introduced into the sputtering cavity, the oxygen content of the sputtering gas is 0.1% to 1%, sputtering is continued, and the ITO film is formed on the surface of the battery intermediate, and obtaining the battery intermediate covered with the ITO film. The sputtering power, the chamber pressure intensity and the oxygen content of the sputtering gas are precisely regulated and controlled through the normal-temperature magnetron sputtering process, the ITO film with high visible light transmittance and low resistivity is prepared, and the problem that thermal damage is easily caused to a perovskite layer and a crystalline silicon bottom battery in a traditional high-temperature preparation method of the ITO film is solved. And the normal-temperature preparation requirement of the laminated perovskite battery is difficult to adapt.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic manufacturing, and in particular relates to a method for preparing room temperature ITO thin film and its application in perovskite solar cells. Background Technology

[0002] In the global transition to renewable energy, crystalline silicon solar cells dominate the photovoltaic market due to their advantages such as material stability and mature technology. However, their photoelectric conversion efficiency is approaching its theoretical limit, and cost has reached a bottleneck. Perovskite solar cells, as a new generation technology, have characteristics such as high light absorption coefficients, significantly improved efficiency, and show great potential.

[0003] To further improve the efficiency of photovoltaic devices, the industry generally adopts a perovskite / silicon heterojunction tandem cell structure, which maximizes energy utilization by absorbing sunlight in segments. Since sunlight needs to enter from the surface of the perovskite top cell, and photogenerated carriers need to flow efficiently between the top and bottom cells to reduce interface losses, traditional non-transparent metal electrodes cannot meet the requirements. ITO thin films need to have both high visible light transmittance and low resistivity, making them the core component for achieving optical and electrical matching of tandem cells.

[0004] Tandem solar cells require sunlight to enter through the perovskite top cell and demand low-loss flow of photogenerated carriers. Therefore, it is essential to use ITO thin films with high visible light transmittance and low resistivity to replace the non-transparent metal electrodes. However, the preparation of existing ITO thin films suitable for perovskite / silicon heterojunction tandem solar cells still faces significant technical challenges. Considering that hydrogen, which plays a passivation role in silicon heterojunction cells, will be released at high temperatures of 200°C, and perovskite cells also require low preparation temperatures, ITO thin films need to be prepared at low temperatures or even room temperature. However, existing processes cannot simultaneously achieve high transmittance and low resistivity at room temperature. Improper parameter matching can easily lead to shortcomings in the optical or electrical properties of the thin film, thus limiting the overall photoelectric conversion efficiency of the tandem solar cell.

[0005] While high sputtering power in existing ITO thin film fabrication processes can reduce the resistivity and improve carrier mobility, it also generates strong ion bombardment, damaging the crystal structure and photoelectric properties of the underlying perovskite material. Conversely, reducing power to protect the perovskite layer leads to increased film resistivity, making it difficult to balance low damage with excellent electrical performance. Oxygen content directly affects the carrier concentration, mobility, and transmittance of ITO thin films; both insufficient and excessive oxygen content degrade film performance, and current processes struggle to consistently and precisely control the oxygen content within the optimal range. Excessively high or low sputtering pressures can also cause various structural defects in ITO films, degrading film performance. Current processes struggle to consistently maintain optimal pressure, affecting the consistency of film performance. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing ITO thin films at room temperature and its application in perovskite solar cells, so as to solve the technical problems that traditional high-temperature preparation of ITO thin films easily causes thermal damage to the perovskite layer and crystalline silicon substrate, and it is difficult to stably balance high visible light transmittance and low resistivity, thus meeting the requirements of tandem perovskite solar cell preparation.

[0007] To achieve the above objectives, the present invention provides a method for preparing a room-temperature ITO thin film and its application in perovskite solar cells, and the specific technical solution is as follows:

[0008] A method for preparing an ITO thin film at room temperature involves placing a battery intermediate to be coated in a magnetron sputtering apparatus. The sputtering power of the magnetron sputtering apparatus is set to 100 W to 300 W, and the chamber pressure is set to 0.1 Pa to 1 Pa. An ITO ceramic target is used as the sputtering source. Sputtering gas is introduced into the sputtering chamber. The oxygen content in the sputtering gas is 0.1% to 1%. Continuous sputtering forms an ITO thin film on the surface of the battery intermediate, resulting in a battery intermediate covered with an ITO thin film.

[0009] As a further improvement of the present invention, the magnetron sputtering equipment has a sputtering power of 210W, a chamber pressure of 0.2Pa, and an oxygen content of 0.4% in the sputtering gas.

[0010] As a further improvement of the present invention, the frequency of the RF sputtering power supply of the magnetron sputtering equipment is 13.56MHz, the ITO ceramic target composition includes 90% In2O3 and 10% SnO2, and the sputtering gas includes Ar and O2.

[0011] A method for preparing a perovskite solar cell, comprising the following steps: ITO thin film prepared using the above method.

[0012] S1. Pretreatment of crystalline silicon substrate: Select a crystalline silicon substrate and perform ultrasonic cleaning, nitrogen drying and ozone treatment in sequence to obtain a pretreated crystalline silicon substrate.

[0013] S2, NiOx thin film preparation: The pretreated crystalline silicon bottom cell is placed in a magnetron sputtering apparatus, and the apparatus is started to pump the pressure in the chamber to 10. -3 Below Pa, a NiOx thin film is deposited on the surface of a crystalline silicon bottom cell by magnetron sputtering; after sputtering, an annealing treatment is performed to obtain a crystalline silicon bottom cell covered with a NiOx thin film;

[0014] S3. Preparation of self-assembled layer: The self-assembled layer of the crystalline silicon bottom cell covered with NiOx film is prepared by spin coating. After spin coating, annealing is performed to obtain an intermediate containing the self-assembled layer.

[0015] S4. Preparation of perovskite layer: Perovskite precursor liquid is spin-coated onto the surface of the intermediate containing the self-assembled layer. After spin-coating, annealing is performed to form a perovskite layer on the surface of the self-assembled layer.

[0016] S5. Electron transport layer preparation: For the intermediate material after completing the perovskite layer preparation, C is deposited using a high-vacuum evaporation device. 60 Layer; then use atomic layer deposition equipment on C 60 A SnO2 layer is deposited on the surface of the layer to form an electron transport layer;

[0017] S6. Preparation of ITO thin film: An ITO thin film is coated on the surface of the electron transport layer using any of the preparation methods described in claims 1-3. The thickness of the ITO thin film is 80-120 nm.

[0018] S7. Silver electrode preparation: Silver grid line electrodes are deposited on the surface of the ITO thin film to obtain a perovskite solar cell.

[0019] As a further improvement of the present invention, in S1, ultrasonic cleaning with detergent for 10-30 min, ultrasonic cleaning with isopropanol / acetone for 10-30 min, ultrasonic cleaning with anhydrous ethanol for 10-30 min are performed, followed by nitrogen drying and ozone treatment for 10-30 min; in S2, magnetron sputtering is performed at room temperature.

[0020] As a further improvement of the present invention, the self-assembled layer in S3 is spin-coated at a speed of 5000 rpm for 30 seconds, and then annealed at 100°C for 10 minutes after spin-coating.

[0021] As a further improvement of the present invention, the preparation of the S4 perovskite layer includes the following steps:

[0022] S4.1, Prepare the perovskite solution: According to the component ratio Cs x FA 1-x Pb(I y Br 1-y 3. Prepare perovskite precursor solution;

[0023] S4.2 Spin Coating Deposition: In a glove box, the perovskite precursor solution is spread evenly on the surface of the intermediate containing the self-assembled layer and spin-coated for 10 seconds at a rotation speed of 1000 rpm and an acceleration of 200 rpm / s; then, the rotation speed is increased to 5000 rpm at an acceleration of 2000 rpm / s and spin-coated for 20 seconds; in the last 3 seconds of spin coating, an anti-solvent is dropped onto the surface of the perovskite precursor solution.

[0024] S4.3 Annealing treatment: After spin coating, anneal at 100℃ for 20 minutes to form a perovskite layer on the surface of the self-assembled layer.

[0025] As a further improvement of the present invention, in S5, a high-vacuum evaporation device is used to deposit 15 nm of C at a rate of 0.05 A / s.60 Layer; then use atomic layer deposition equipment on C 60 A 15nm SnO2 layer is deposited on the surface of the layer.

[0026] As a further improvement of the present invention, S7 uses a high vacuum evaporation equipment to deposit 200nm silver grid line electrodes.

[0027] A perovskite solar cell is prepared using the above-described method for preparing perovskite solar cells.

[0028] Beneficial effects:

[0029] The preparation method of this application clearly states that the entire ITO thin film preparation process does not require heating. In silicon heterojunction bottom cells, hydrogen, which plays a passivation role, is easily released at temperatures above 200°C, leading to a weakening of the passivation effect. Simultaneously, the perovskite top cell material is temperature-sensitive, and high temperatures can easily induce grain boundary migration, component decomposition, or phase transformation. The room-temperature preparation characteristic of this application fundamentally avoids the aforementioned thermal damage problems, ensuring the passivation performance of the crystalline silicon bottom cell and the crystal structure integrity of the perovskite layer in the tandem cell. This lays the foundation for efficient photoelectric conversion in subsequent cells and solves the problem of poor compatibility between traditional high-temperature prepared ITO thin films and the sensitive substrate of the lower layer in tandem cells.

[0030] The coordinated control of sputtering power and chamber pressure can adjust the sputtering particle energy and film deposition density, avoiding the problems of film porosity and increased resistivity caused by low power, and preventing excessive ion bombardment caused by excessive power, thus ensuring the uniformity of film structure. The limitation of oxygen content range can accurately balance the carrier concentration and mobility of ITO film. Too low oxygen content will lead to too many oxygen vacancies, high carrier concentration and decreased long-wavelength transmittance, while too high oxygen content will easily introduce defects and reduce mobility. The oxygen content limitation of this method can achieve the synergy of "low resistivity" and "high visible light transmittance", meeting the dual requirements of "high light incident efficiency + low carrier transport loss" for ITO film in tandem solar cells.

[0031] This application does not require the development of additional dedicated heating or cooling devices; it can be achieved directly using industrially mature magnetron sputtering equipment. This reduces manufacturing costs, promotes the industrialization of tandem solar cells, and allows for rapid integration into existing photovoltaic device production lines, thereby reducing equipment investment costs. Attached Figure Description

[0032] Figure 1 This is a graph showing the variation of ITO film thickness with sputtering power.

[0033] Figure 2 The graph shows the carrier concentration and mobility of the ITO thin film as a function of sputtering power.

[0034] Figure 3 The graph shows the transmittance of the ITO thin film as a function of sputtering power.

[0035] Figure 4 This is a graph showing the change in ITO film thickness as a function of oxygen content.

[0036] Figure 5 The graph shows the changes in carrier concentration and mobility of ITO thin films as a function of oxygen content.

[0037] Figure 6 This is a graph showing the change in transmittance of ITO thin film with oxygen content.

[0038] Figure 7 This is a graph showing the variation of ITO film thickness with sputtering pressure.

[0039] Figure 8 The graph shows the carrier concentration and mobility of the ITO thin film as a function of sputtering pressure.

[0040] Figure 9 This is a graph showing the transmittance of an ITO thin film as a function of sputtering pressure.

[0041] Figure 10 This is a graph showing the electrical performance of ITO thin film in perovskite solar cells. Detailed Implementation

[0042] To better understand the purpose, structure, and function of this invention, the following detailed description, in conjunction with the accompanying drawings, provides a method for preparing a room-temperature ITO thin film and its application in perovskite solar cells.

[0043] Implementation example:

[0044] The room-temperature ITO thin film preparation method of this application precisely controls the sputtering power, chamber pressure and oxygen content of sputtering gas through room-temperature magnetron sputtering process to prepare ITO thin films with both high visible light transmittance and low resistivity. This solves the problem that traditional high-temperature ITO thin film preparation can easily cause thermal damage to the perovskite layer and crystalline silicon bottom cell, and is difficult to adapt to the low-temperature preparation requirements of tandem perovskite cells.

[0045] The carrier concentration and mobility of the ITO thin film were measured using a nano-metric Hall effect testing system, and the transmittance of the ITO thin film was measured using a METASH UV-8000 UV-Vis spectrophotometer. The surface roughness of the ITO thin film was measured using AFM (Dimension IcON (Bruker)), and the surface morphology of the ITO thin film was measured using SEM (Gemini 300 (Zeiss)). The perovskite / silicon heterojunction tandem solar cell was tested under AM1.5 light intensity (G2V LED lamp array), and the temperature of the test platform was maintained at approximately 25°C.

[0046] The conductivity of ITO thin films is mainly due to the charge carriers provided by oxygen vacancies and the charge carriers provided by Sn doping. One Sn 4+ For In 3+ An oxygen vacancy can provide one charge carrier, while a single oxygen vacancy can provide two charge carriers simultaneously. Sputtering power is crucial to the photoelectric properties of ITO thin films, primarily by influencing the sputtered particle energy, which in turn affects the film's density. Figure 1 It can be seen that as the sputtering power increases, the film thickness increases linearly. This is because, under the same pressure conditions, increasing the sputtering power increases the sputtering yield, which in turn increases the deposition rate and thus increases the film thickness.

[0047] Figure 2 The carrier concentration and mobility of the ITO thin film vary with sputtering power. As sputtering power increases, the carrier concentration gradually rises because at higher sputtering power, the energy density of the sputtering process gradually increases, leading to an increase in the number of reactive oxygen species. Higher sputtering particle energy causes the substrate temperature to rise with increasing power, enhancing the substrate's adsorption capacity for reactive oxygen species, thus gradually increasing the oxygen vacancy concentration and consequently the carrier concentration. Furthermore, increased power promotes the growth of Sn... 4+ Incorporating In₂O₃ into the lattice further increases the carrier concentration. Carrier mobility initially increases with increasing sputtering power, reaching its maximum of 19 cm⁻¹ at 270 W. 2 / v·s, and then decreased to 12.8cm as sputtering power continued to increase. 2 / v·s. A possible reason is that the lattice defects in the ITO thin film initially decrease with increasing sputtering power, leading to a further increase in mobility. However, with further increases in sputtering power, the carrier concentration in the ITO thin film further increases, increasing its impact on carrier mobility. Additionally, excessively high sputtering power leads to an increase in the number of defects within the film, and these defects interact strongly with carriers, hindering carrier movement. Therefore, with further increases in sputtering power, carrier mobility actually decreases.

[0048] The transmittance of ITO thin films can be mainly divided into two regions: short-to-medium wavelength and long-wavelength, and the influencing factors are also different. In the short-to-medium wavelength region, the transmittance of the film mainly depends on the bandgap of the material itself; while in the long-wavelength region, the transmittance is closely related to the carrier concentration. When the carrier concentration is high, its interaction with the incident light will be significantly enhanced, which will lead to a decrease in the transmittance of the film in the long-wavelength region. Figure 3The effect of sputtering power on the transmittance of ITO thin films was shown. As the sputtering power increased, the transmittance first increased and then decreased. The average transmittance was highest at 210W, reaching 73.68%. This may be because as the sputtering power increased, the thin film grains increased and the defects decreased, thus leading to an increase in the transmittance. However, as the sputtering power continued to increase, it destroyed the microstructure and introduced new defects, which in turn caused the transmittance to decrease.

[0049] like Figure 1-3 As shown, although the mobility is optimal at 270W (19cm) 2 The transmittance is 100 Ω·s, and the resistivity is also the lowest (2.27E-04 Ω·cm). However, the high sputtering power of 270 W will affect the underlying perovskite layer. At 210 W, the transmittance is optimal, with a mobility of 16.8 cm⁻¹. 2 With a resistivity of 4.12E-04Ω·cm, which is not much different from 270W, the sputtering power was temporarily set to 210W to adjust the oxygen content and pressure parameters, so that the film performance could reach the optimal level.

[0050] Oxygen content is also one of the key parameters determining the structure, electrical properties, optical properties, and stability of ITO thin films. Insufficient, suitable, or excessive oxygen content will directly affect the final performance by influencing the crystal structure, carrier concentration, defect concentration, and state of the thin film. Figure 4 It can be seen that the thickness of the ITO film gradually decreases with the increase of oxygen content. This is because when the oxygen content increases, the proportion of argon gas decreases under the same pressure conditions. This leads to a decrease in the number of argon ions that collide with the target surface per unit time, a decrease in the number of atoms or molecules sputtered from the target surface, and a decrease in the total amount of material deposited on the substrate to form a film. This results in a decrease in the deposition rate and a corresponding decrease in the film thickness.

[0051] The mobility (μ) and carrier concentration (n) of ITO thin films are the main factors determining their electrical properties, and their relationship with resistivity (ρ) is: ρ = 1 / (n*e*μ), where e is the electron charge (1.602 × 10⁻¹⁹ C). This formula shows that resistivity is inversely proportional to both carrier concentration and mobility; the higher the carrier concentration and electron mobility, the lower the resistivity of the thin film, and the stronger its conductivity. Figure 5It can be seen that with increasing oxygen content, the carrier concentration in the ITO film gradually decreases, while the mobility initially increases, reaches a peak, and then decreases again. ITO film is an n-type semiconductor transparent conductive oxide film, whose conductivity mainly relies on oxygen vacancies and heteroatom doping to provide carriers. When the oxygen content is low, there are many oxygen vacancies in the ITO film; one oxygen vacancy can provide two electrons, resulting in a high carrier concentration, low mean free time, and low mobility. Additionally, the presence of numerous oxygen vacancies and lattice distortion defects also reduces mobility. As the oxygen content gradually increases, oxygen atoms fill the vacancies, reducing the density of defects such as lattice distortion and dislocations. Simultaneously, the oxygen vacancies in the film are gradually filled, reducing the source of carriers and leading to a decrease in carrier concentration. The reduced number of electrons per unit volume significantly decreases the intensity of ionized impurity scattering, thus prolonging the mean free time of carriers and increasing mobility. Furthermore, the weakening of lattice scattering further enhances mobility. In addition, excessive oxygen atoms may exist in the thin film as impurities, enhancing the scattering of charge carriers. This will also affect the migration and conduction of charge carriers to some extent. Therefore, the migration rises first, reaches its peak, and then decreases.

[0052] Here, the ITO film exhibits the highest mobility of 16.8 cm⁻¹ when the oxygen content is 0.4%. 2 / v·s, and the resistivity is also the lowest at 3.26E-04Ω·cm. Figure 6 The graph shows the transmittance of the ITO thin film as a function of oxygen content. With increasing oxygen content, the average transmittance of the film initially increases and then decreases. The best transmittance is observed in the long-wavelength region at an oxygen content of 0.4%, with an average transmittance of 73.85% in the visible light range. This is likely because as the oxygen content increases, the introduced oxygen atoms gradually fill excess oxygen vacancies, minimizing free carrier absorption and resulting in better crystal quality, thus achieving the highest visible light transmittance. However, with continued addition of oxygen, the crystal quality of the film decreases, defects increase, and light scattering and absorption become more severe, leading to a continuous decline in transmittance.

[0053] Sputtering pressure is also a factor affecting the photoelectric properties of thin films. This is mainly manifested in its ability to indirectly alter the photoelectric characteristics of the film by changing the number and kinetic energy of particles during sputtering, thereby further affecting the deposition rate of the film. Figure 7 As can be seen, the film thickness gradually decreases as the sputtering pressure gradually increases. This is because as the sputtering pressure increases, the molecular free path in the chamber gradually shortens, which in turn affects the deposition rate of the film and reduces the film thickness.

[0054] Figure 8The graph shows the relationship between sputtering pressure and carrier concentration and mobility of ITO thin films. As can be seen, the carrier concentration of the film decreases significantly with increasing sputtering pressure. This is because as the sputtering pressure increases, the sputtering gas density increases and the mean free path shortens. The sputtered particles collide frequently with argon atoms during their movement towards the substrate, resulting in significant energy loss and a less dense deposited film. Furthermore, Sn4... + O2 was not effectively doped, further reducing the carrier concentration. The mobility also decreased with increasing sputtering pressure, reaching a maximum of 16.8 cm⁻¹ at 0.2 Pa. 2 / v·s, but with further increases in sputtering pressure, the mobility is only 4.39cm at 0.6Pa. 2 / v·s.

[0055] from Figure 9 It can be seen that as the sputtering pressure increases, the average transmittance of the film first rises and then decreases, reaching a maximum of 73.83% at 0.2 Pa. This may be because as the sputtering pressure increases, the mean free path of the sputtered atoms becomes very short. As the atoms fly towards the substrate, they will collide frequently with a large number of argon atoms, generating more defects and causing the film transmittance to decrease.

[0056] ITO thin films were prepared at room temperature by adjusting the radio frequency magnetron sputtering process parameters. The effects of sputtering power, oxygen content and sputtering pressure on ITO thin films were analyzed, and suitable process parameters were determined. As sputtering power increases, film thickness gradually increases, resistivity initially decreases significantly and then increases slightly, reaching a minimum of 2.72E-04 Ω·cm at 270W, exhibiting an initial increase followed by a decrease. However, 270W is unsuitable for the top electrode process of tandem solar cells, so the sputtering power is tentatively set at 210W for oxygen content and pressure optimization. As oxygen content increases, film thickness gradually decreases, with resistivity reaching a minimum of 3.26E-04 Ω·cm at an oxygen content of 0.4%, exhibiting an initial increase followed by a decrease. As sputtering pressure increases, film thickness gradually decreases, while resistivity increases significantly, reaching a minimum of 4.12E-04 Ω·cm at 0.2Pa, exhibiting an initial increase followed by a decrease. ITO films prepared at sputtering power of 210W, oxygen content of 0.4%, and pressure of 0.2Pa achieve an efficiency of up to 31.58% when applied in perovskite tandem solar cells.

[0057] A method for preparing a perovskite solar cell using a room-temperature ITO thin film specifically includes the following steps:

[0058] Step 1: Take the crystalline silicon substrate and ultrasonically clean it with detergent at 40kHz for 15 minutes to remove oil and dirt from the substrate surface. Then, transfer it to an acetone solution and ultrasonically clean it for another 15 minutes to remove detergent residue. Next, transfer it to anhydrous ethanol solution and ultrasonically clean it for 15 minutes to remove residual acetone and water-soluble impurities. Dry the substrate surface with high-purity nitrogen at a flow rate of 10L / min to prevent moisture from reducing the adhesion of subsequent film layers. Place the dried substrate in an ozone treatment instrument and treat it at an ozone concentration of 50ppm and a temperature of 25℃ for 15 minutes. Ozone oxidation removes residual organic matter on the substrate surface and introduces hydroxyl groups, improving the adhesion and interfacial bonding strength of the subsequent NiOx film. Through multi-step cleaning and ozone treatment, a clean and hydrophilic crystalline silicon substrate is obtained, laying the foundation for the uniform deposition of subsequent film layers.

[0059] Step 2: Place the pretreated crystalline silicon bottom cell into the magnetron sputtering equipment, fix the sample stage (at room temperature 25℃, without heating), install the NiOx target, and evacuate the chamber to a vacuum of 6*10⁻⁻⁻⁶. 4 The process begins at Pa; pure Ar gas is introduced at a flow rate of 80 sccm, the chamber pressure is adjusted to 0.4 Pa, the sputtering power is set to 200 W, and sputtering is performed for 10 min to deposit a 20 nm thick NiOx film on the surface of the crystalline silicon base cell. This is the optimal thickness for the hole transport layer, balancing hole transport efficiency and light transmittance. After sputtering, the sample is removed and placed in an annealing furnace at 200 °C for 60 min in air to promote NiOx film crystallization, improve its conductivity and hole mobility, and repair interface defects generated during sputtering. The NiOx film, as the hole transport layer of the perovskite solar cell, is responsible for collecting photogenerated holes generated in the perovskite layer and transporting them to the crystalline silicon base cell, while simultaneously blocking electrons from transporting back to the electrodes, reducing carrier recombination.

[0060] Step 3: Transfer the substrate covered with the NiOx film to a glove box (N2 atmosphere, water and oxygen ≤0.1ppm). Take 0.1mmol / L SAM solution (such as Me-4PACz solution) and add 50μL to the NiOx film surface. Start the spin coater, set the speed to 5000rpm and the spin coating time to 30s. During the spin coating process, the SAM solution uniformly covers the NiOx surface. After spin coating, place the substrate in the annealing station in the glove box and anneal at 100℃ for 10min to promote the bonding of SAM molecules with the hydroxyl groups on the NiOx surface, forming a dense self-assembled layer. The SAM layer can modify the interface between NiOx and the perovskite layer, reduce interface defects (such as uncoordinated Pb²+), and reduce hole transport resistance; at the same time, it can inhibit the non-uniform growth of the perovskite layer on the NiOx surface and improve the perovskite crystal quality.

[0061] Step 4: According to the component ratio Cs0.07 FA 0.93 Pb(I 0.93 Br 0.07 3. Weigh CsI, FAI, PbI2, and PbBr2, dissolve them in 1 mL of a mixed solvent (DMF:DMSO = 4:1, volume ratio), stir at 60℃ for 2 h, and filter to obtain a 1.7 mol / L perovskite precursor solution to ensure uniform film thickness after spin coating. In a glove box, add 60 μL of the perovskite precursor solution to the surface of the SAM layer and start the spin coater: First stage (pre-spin coating): 1000 rpm rotation speed, 200 rpm / s acceleration, for 10 s to ensure uniform spreading of the precursor solution and avoid local accumulation; increase the rotation speed to 5000 rpm with an acceleration of 2000 rpm / s for 20 s to remove excess solvent by centrifugation and control film thickness; in the last 3 s of the main spin coating, add 250 μL of chlorobenzene (anti-solvent) to the film surface with a pipette to induce rapid nucleation of perovskite crystals and reduce grain boundary defects. The spin-coated substrate was placed in an annealing station inside a glove box and annealed at 100°C for 20 minutes to promote perovskite crystal growth, remove residual solvent, and form a dense, pinhole-free perovskite layer. The perovskite layer is the "light absorption core" of the battery, which can efficiently absorb photons in the visible light range and generate photogenerated carriers, providing a source for subsequent carrier separation and transport.

[0062] Step 5: Transfer the intermediate containing the perovskite layer to a high-vacuum evaporation equipment, and evacuate the vacuum value to 5*10⁻. 4 The process begins at Pa; C is added. 60 Powder was used, and the evaporation rate was set to 0.05 A / s. The thickness was monitored using a quartz crystal film thickness gauge, and evaporation was stopped when the thickness reached 15 nm. (C) 60 The layer is responsible for rapidly collecting electrons generated by the perovskite layer and blocking the reverse transport of holes. The C-deposited layer is then... 60 The intermediate was then transferred to an ALD (Alternating Discharge) device, where tin tetrachloride was used as the metal source and deionized water as the oxygen source. 0.1 nm of SnO2 was deposited per cycle, for a cumulative deposition of 15 nm. The SnO2 layer further improved electron transport efficiency and served as a protective layer to reduce the impact of subsequent ITO sputtering on C. 60 Damage to the layer. The electron transport layer forms an "electron fast channel" that transports electrons generated in the perovskite layer to the ITO thin film, while simultaneously achieving effective "hole-electron" separation and reducing carrier recombination losses.

[0063] Step Six: Transfer the intermediate containing the completed electron transport layer to a glove box and let it stand for 8 minutes to remove trace amounts of inert gas impurities adsorbed on the surface. This prevents impurities from embedding into the ITO film during subsequent sputtering, which could affect the film's density and conductivity. Then, fix the intermediate onto the sample stage of the magnetron sputtering equipment, setting the target-substrate distance between the intermediate surface and the ITO ceramic target to 13.5 cm to optimize the sputtering particle movement path and ensure film uniformity. First, use a mechanical pump to evacuate the chamber pressure to below 10 Pa, then start the molecular pump to evacuate the chamber's base vacuum to 6*10 Pa. -4 To minimize the impact of residual air in the chamber on the purity of the sputtering gas and prevent impurities such as O2 and N2 from reacting with sputtering particles to generate defects, the RF sputtering power supply frequency was set to 13.56 MHz. An ITO ceramic target with a composition of 90% In2O3 and 10% SnO2 was installed, and the sputtering power was set to 150 W. Pre-sputtering was performed for 5 minutes, followed by the introduction of a mixed sputtering gas of Ar and O2. The Ar gas flow rate was set to 99.6 sccm and the O2 gas flow rate to 0.4 sccm using a mass flow controller to ensure an oxygen content of 0.4% in the sputtering gas, precisely balancing the oxygen vacancy concentration in the ITO film. Simultaneously, the chamber valves were adjusted to stabilize the chamber sputtering pressure at 0.2 Pa. The sputtering power of the magnetron sputtering equipment was set to 210 W to avoid thin film porosity and increased resistivity due to low power, while also preventing excessive ion bombardment caused by high power. The sputtering program was then initiated. The deposition thickness of the ITO film was monitored in real time using a quartz crystal film thickness gauge. When the thickness reached 80 nm, the sputtering power supply and gas valves were shut off. Throughout the process, the sample stage was maintained at room temperature (25°C) to prevent the electron transport layer from decomposing or to generate interfacial thermal stress with the ITO layer due to high temperatures, thus solving the problem of poor film compatibility during traditional high-temperature ITO preparation. The chamber was kept under vacuum for 10 minutes to allow the ITO film to cool naturally to room temperature, preventing rapid cooling that could cause cracking. Then, high-purity N2 (50 sccm flow rate) was slowly introduced into the chamber through a nitrogen filling valve until the chamber pressure reached atmospheric pressure equilibrium. The ITO film, acting as the "transparent top electrode" of the battery, possesses both high visible light transmittance (ensuring sunlight enters the perovskite layer) and low resistivity (reducing electron transport losses), achieving the core function of "light incident - electrical conduction," while also providing good electrode contact for subsequent Ag grid lines.

[0064] Step 7: Transfer the intermediate covered with the ITO film to a high vacuum evaporation equipment, install Ag particles, and evacuate the chamber to a vacuum level of 5*10⁻⁻⁻⁶. 4 The process begins at Pa. The Ag deposition rate is set to 0.2 A / s to balance deposition efficiency and film quality. A 200 nm thick silver gate electrode is deposited using a mask. The Ag gate electrode acts as a "carrier collection terminal," efficiently collecting electrons transported by the ITO thin film and converting them into external circuit current, reducing the electrode's own resistive losses.

[0065] The stacked electrical properties of the fabricated perovskite solar cells were tested under AM1.5 spectroscopy, and are shown in Table 1.

[0066] Voc / V Jsc mA / cm2 Fill Factor R@Voc(Ohm) Rsh@Jsc(Ohm) PCE (%) 1.80 21.39 81.91 2.43 4074.68 31.58

[0067] Table 1. Electrical performance of ITO thin film in tandem perovskite solar cells

[0068] Combination Figure 10 As shown, by adjusting the process parameters of the magnetron sputtering equipment, the electrical performance of the ITO thin film prepared at room temperature in a perovskite tandem solar cell reached an efficiency of 31.58%, a voltage of 1.80V, and a current density of 21.39mA / cm². 2 The fill rate is 81.91%.

[0069] Existing high-temperature fabrication processes easily lead to grain boundary migration, component decomposition, or phase transformation in the perovskite layer. They also cause hydrogen atoms, which play a passivation role in the crystalline silicon base cell, to be released, weakening the passivation effect. This application eliminates the need for heating, completely avoiding the aforementioned thermal damage, ensuring the integrity of the perovskite layer's crystal structure and the passivation performance of the crystalline silicon base cell, and solving the problem of poor compatibility between existing processes and sensitive substrates in tandem perovskite cells. Existing high-temperature processes require additional heating devices, increasing equipment investment and maintenance costs, and consuming significant amounts of energy. This application eliminates the heating step, requiring no additional energy consumption, and shortens the process cycle (eliminating heating and cooling steps), reducing energy consumption and time costs during production, and better meeting the needs of low-carbon industrialization. During existing high-temperature fabrication, the difference in thermal expansion coefficients between the ITO film and the underlying electron transport layer and perovskite layer easily generates thermal stress, leading to interface delamination or increased defects. This application's room-temperature sputtering reduces the interlayer temperature gradient, allowing the ITO film to form a tight bond with the underlying film, reducing interface resistance and carrier recombination losses, and ensuring the long-term stability of the battery.

[0070] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A method for preparing an ITO thin film at room temperature, characterized in that, The battery intermediate to be coated is placed in a magnetron sputtering device, the sputtering power of the magnetron sputtering device is set to 100 W-300 W, the chamber pressure is 0.1 Pa-1 Pa, an ITO ceramic target is used as a sputtering source, a sputtering gas is introduced into the sputtering chamber, the oxygen content in the sputtering gas is 0.1%-1%, and the battery intermediate is continuously sputtered to form an ITO thin film on the surface of the battery intermediate, thereby obtaining a battery intermediate covered with the ITO thin film.

2. The method of claim 1, wherein the ITO thin film is prepared at room temperature. The sputtering power of the magnetron sputtering device is 210 W, the chamber pressure is 0.2 Pa, and the oxygen content in the sputtering gas is 0.4%.

3. The method of claim 1, wherein the ITO thin film is prepared at room temperature. The frequency of the radio frequency sputtering power source of the magnetron sputtering device is 13.56 MHz, the components of the ITO ceramic target include 90% of In2O3 and 10% of SnO2, and the sputtering gas includes Ar and O2.

4. A method for preparing a perovskite cell, characterized in that the ITO thin film is prepared by the method according to any one of claims 1 to 3. The method comprises the following steps: S1, pre-treatment of the crystalline silicon bottom cell: selecting a crystalline silicon bottom cell substrate, sequentially performing ultrasonic cleaning, nitrogen drying and ozone treatment, and obtaining a pre-treated crystalline silicon bottom cell; S2, NiOx film preparation: the pretreated crystalline silicon bottom cell is placed in a magnetron sputtering device, the device is started, the pressure in the chamber is extracted to 10 -3 Pa, and NiOx film is deposited on the surface of the crystalline silicon bottom cell by magnetron sputtering; after sputtering, annealing treatment is performed to obtain a crystalline silicon bottom cell covered with NiOx film; S3, preparation of a self-assembled layer: preparing a self-assembled layer on the crystalline silicon bottom cell covered with the NiOx thin film by using a spin coating method, performing annealing treatment after the spin coating is completed, and obtaining an intermediate containing the self-assembled layer; S4, preparation of a perovskite layer: spin coating perovskite precursor solution on the surface of the intermediate containing the self-assembled layer by using a spin coating method, performing annealing treatment after the spin coating is completed, and forming a perovskite layer on the surface of the self-assembled layer; S5, electron transport layer preparation: for the intermediate after the preparation of perovskite layer, use high vacuum evaporation equipment to evaporate C 60 layer; then use atomic layer deposition equipment to deposit SnO2 layer on the surface of C 60 layer, form electron transport layer; S6, preparation of an ITO thin film: covering an ITO thin film on the surface of the electron transport layer by using any one of the preparation methods in claims 1-3, and the thickness of the ITO thin film is 80-120 nm; S7, preparation of a silver electrode: evaporating a silver grid electrode on the surface of the ITO thin film, and obtaining a perovskite battery.

5. The method of claim 4, wherein the perovskite cell is prepared by the steps of: In S1, the crystalline silicon bottom cell is ultrasonically cleaned for 10-30 min by using a detergent, ultrasonically cleaned for 10-30 min by using isopropyl alcohol / acetone, and ultrasonically cleaned for 10-30 min by using anhydrous ethanol, and then nitrogen drying and ozone treatment are performed for 10-30 min; and in S2, the magnetron sputtering is performed at room temperature.

6. The method of claim 4, wherein the perovskite cell is prepared by the steps of: In S3, the spin coating of the self-assembled layer is performed at a rotation speed of 5000 rpm for 30 s, and then annealing treatment is performed at 100℃ for 10 min after the spin coating is completed.

7. The method for preparing a perovskite solar cell according to claim 4, characterized in that, S4, preparation of a perovskite layer, comprises the following steps: S4.1, configuration of perovskite solution: according to component ratio Cs x FA 1-x Pb(I y Br 1-y )3configuration of perovskite precursor solution; S4.2, spin coating deposition: spreading the perovskite precursor solution on the surface of the intermediate containing the self-assembled layer in a glove box, spin coating at a rotation speed of 1000 rpm and an acceleration of 200 rpm / s for 10 s; then increasing the rotation speed to 5000 rpm at an acceleration of 2000 rpm / s for 20 s; and then dropping an anti-solvent on the surface of the perovskite precursor solution in the last 3 s of the spin coating; S4.3, annealing treatment: performing annealing treatment at 100℃ for 20 min after the spin coating is completed, and forming a perovskite layer on the surface of the self-assembled layer.

8. The method of claim 4, wherein the perovskite cell is prepared by the steps of: In S5, a high vacuum evaporation equipment was used to evaporate 15 nm of C at a rate of 0.05 A / s 60 layer; an atomic layer deposition equipment was then used to deposit a 15 nm layer of SnO2 on the surface of the C 60 layer. ​ 9. The method of claim 4, wherein the perovskite cell is prepared by the steps of: In S7, a silver grid electrode with a thickness of 200 nm is evaporated by using a high-vacuum evaporation device. ​ 10. A perovskite cell, characterized in that, The preparation method is prepared by using any one of the preparation methods in claims 4-9. The preparation method is prepared by using any one of the preparation methods in claims 4-9.

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