Hole transport layer of trans-perovskite solar cell and preparation method of hole transport layer

Abstract

The invention relates to the technical field of photovoltaic solar cells, and discloses a hole transport layer of a trans-perovskite solar cell and a preparation method, the hole transport layer is a double-layer composite NiOx thin film compounded by a reaction magnetron sputtering NiOx thin film and an atomic layer deposition NiOx thin film, the reaction magnetron sputtering NiOx thin film is deposited on a conductive substrate, and the thickness of the reaction magnetron sputtering NiOx thin film is 5-50 nm; and the thickness of the NiOx thin film deposited by the atomic layer is 3-30nm. The hole transport layer provided by the invention has high conductivity and excellent interface quality, and can effectively reduce the non-radiative recombination of the perovskite light absorption layer / hole transport layer interface, thereby improving the photoelectric conversion performance and steady-state output performance of the trans-perovskite solar cell. And the preparation method of the hole transport layer provided by the invention is the combination and adjustment of the existing process, can be produced by using the existing equipment, and is easy to be compatible with the large-area industrial production process.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic solar cell technology, specifically to a hole transport layer and its preparation method for an inverted perovskite solar cell. Background Technology

[0002] In recent years, perovskite solar cells (PSCs) have become one of the most promising photovoltaic devices due to their rapid improvement in photoelectric conversion efficiency (PCE) and low cost. Among them, inverted (pin) perovskite solar cells have attracted much attention due to their simple fabrication process, low hysteresis effect, and good stability. The layer structure of an inverted perovskite solar cell is, in sequence, a conductive substrate / hole transport layer / perovskite layer / electron transport layer / metal electrode, where the hole transport layer (HTL) is one of the key factors determining the performance of inverted PSCs.

[0003] Nickel oxide (NiO) x NiO, as a p-type metal oxide, possesses high charge mobility and intrinsic stability, and has been widely used in inverted PSCs devices. HTL, a widely used material in inverted PSCs devices, is... x One of its advantages is the versatility of its preparation methods. Typically, there are two methods for depositing NiO. x There are two main methods for creating hole transport layers: chemical deposition and physical vapor deposition. Compared to chemical deposition, physical vapor deposition is more suitable for NiO. x Thin film surface morphology design, roughness and thickness control have certain advantages, and depositing NiO with appropriate thickness and certain conductivity has certain advantages. x Thin films are crucial to the performance of PSCs devices.

[0004] Magnetron sputtering and atomic layer deposition (ALD) are currently the main methods for depositing NiO. x Physical vapor deposition (PVD) methods commonly used for thin films each have their own advantages and disadvantages. Magnetron sputtering is easy to use for large-area fabrication, produces films with good adhesion, and allows for effective adjustment of NiO thickness by controlling sputtering parameters. x While NiO grown using ALD (Alternating Layer Deposition) technology offers superior stoichiometry and electrical properties, high-energy particles can damage the substrate or underlying layer, and the film may contain defects such as pinholes. ALD technology, on the other hand, can grow extremely dense, uniform, pinhole-free films with excellent step coverage, causing minimal damage to the underlying layer and enabling atomic-level precision control of composition and thickness. However, its deposition rate is slower, and the NiO grown using ALD... x The intrinsic conductivity of thin films is usually low. Summary of the Invention

[0005] To address the problems mentioned in the background art, the present invention aims to provide a hole transport layer for inverted perovskite solar cells and a method for its fabrication. This invention addresses the limitations of current methods for controlling energy level structure and defect state density in deposited nickel oxide HTL layers, which makes it difficult to simultaneously achieve efficient hole extraction and excellent interface passivation. The present invention improves the photoelectric conversion performance and steady-state output performance of inverted PSCs devices.

[0006] To achieve the above-mentioned technical effects, the present invention provides the following technical solution.

[0007] First, this invention provides a hole transport layer for an inverted perovskite solar cell, which is a reactive magnetron sputtered NiO layer. x Thin film and atomic layer deposition of NiO x Thin film composite bilayer NiO x Thin film, the reactive magnetron sputtered NiO x A thin film with a thickness of 5-50 nm is deposited on a conductive substrate; the atomic layer is deposited as NiO. x The thickness of the thin film is 3-30 nm.

[0008] Preferably, the reactive magnetron sputtering NiO x The film thickness is 10-30 nm; the atomic layer deposition NiO x The thickness of the thin film is 5 nm.

[0009] Secondly, the present invention also provides a method for preparing the above-mentioned hole transport layer, which includes the following steps: Step 1: Reactive magnetron sputtering of NiO x Thin film: The conductive substrate is placed in the cavity of the vacuum magnetron sputtering system, and the cavity is evacuated to a background vacuum level of less than 2.0 × 10⁻⁶. -6 After Pa, argon and oxygen are introduced into the cavity to deposit a 5-50 nm thick NiO layer on the conductive substrate. x The first film layer is obtained. During the deposition process, the temperature of the conductive substrate is controlled at 20-25℃, the sputtering power is 80-150W, and the working gas pressure is 0.1-1.0Pa. The flow rate of argon gas into the cavity is 30-100sccm, and the flow rate of oxygen gas into the cavity is 1-5sccm. Step 2: Atomic layer deposition of NiO x Thin film: The first film layer is transferred into the ALD reaction chamber, and the temperature inside the ALD reaction chamber is controlled at 150-250℃. The NiO layer in the first film layer... x NiO 3-30 nm thick was cyclically deposited on the thin film using ALD. x Thin film; the ALD cyclic deposition is repeated 100-300 times; The sequence of a single ALD deposition in the ALD cyclic deposition includes: A. Pulsed nickel metal precursor: The nickel metal precursor is pulsed into the ALD reaction chamber for 0.5-2 seconds; B. First purging: Purge the ALD reaction chamber with nitrogen for 10-30 seconds; C. Pulsed reaction oxidant: The reactive oxidant is pulsed into the ALD reaction chamber for 2-5 seconds; D. Second purging: Purge the ALD reaction chamber with nitrogen for 10-30 seconds.

[0010] Furthermore, the nickel metal precursor is selected from any one of bis(cyclopentadiene)nickel, nickel acetylacetonate, and nickel amide.

[0011] Furthermore, the oxidant used in the reaction is selected from ozone, oxygen plasma, and water vapor.

[0012] Furthermore, in step 1, the NiO nanoparticles are reactively magnetron sputtered on the conductive substrate. x The thickness of the thin film is 10-30 nm.

[0013] Furthermore, the NiO deposited in step 2 by ALD cycling x The thickness of the thin film is 5 nm.

[0014] Furthermore, the NiO deposited in step 1 x The thin film is annealed before atomic layer deposition in step 2. NiO x Annealing can optimize the crystallinity of the thin film and adjust the nickel vacancy concentration, thereby further improving its conductivity.

[0015] Furthermore, the annealing treatment is performed at a temperature of 150-350°C for 30-60 minutes, and the annealing atmosphere is selected from at least one of air, oxygen, and nitrogen.

[0016] In existing technologies, reactive magnetron sputtering of NiO x Thin films, due to insufficient density and interface defects, exhibit severe interfacial recombination with the perovskite layer, reducing the open-circuit voltage of the device. Furthermore, high-energy particles pose a potential damage risk to sensitive substrates (such as ITO or the underlying perovskite) and easily generate defects at the interface. In contrast, NiO deposited by ALD... x Although the thin film is uniform and dense, its intrinsic conductivity is relatively low, limiting the longitudinal transport capability of holes, leading to increased series resistance and making it difficult to achieve optimal fill factor and short-circuit current. This invention creatively combines reactive magnetron sputtering and ALD deposition techniques. By defining a specific stacking sequence, NiO is first magnetron sputtered onto a conductive substrate. xThe thin film provides an efficient hole transport path to achieve a high fill factor and short-circuit current, while the NiOx thin film deposited on the upper ALD layer provides a dense and defect-free interface to effectively passivate interface defects, improve the open-circuit voltage and stability of the device, thus achieving complementary advantages between the two.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The hole transport layer provided by this invention possesses both high conductivity and excellent interface quality, effectively reducing nonradiative recombination at the perovskite light-absorbing layer / hole transport layer interface, thereby improving the photoelectric conversion performance and steady-state output performance of inverted perovskite solar cells. Furthermore, the method for fabricating the hole transport layer provided by this invention is a combination and adjustment of existing processes, which can be used for production with existing equipment and is easily compatible with large-area industrial production processes. Attached Figure Description

[0018] Figure 1 The figures show the contact angle test results of films 1 to 3 prepared in Example 1 of this invention; Figure 2 The steady-state fluorescence spectrum (PL) of Example 2 of the present invention; Figure 3 This is the time-resolved fluorescence spectrum (TRPL) of Example 2 of the present invention. Figure 4 The JV curve of the inverted perovskite solar cell prepared in Example 3 of this invention; Figure 5 The steady-state output power curve of the battery device prepared in Example 3 of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative of the present invention and should not be considered as the entirety of the invention or as a limitation or restriction of the technical solution of the present invention. Unless otherwise specified, the materials and reagents used in the following embodiments can be obtained through conventional commercial channels.

[0020] Example 1: Study on NiO prepared by different methods x Wettability of the film Take three identical ITO transparent conductive substrates, and deposit NiO of the same thickness on each substrate according to the preparation method described below. x The thin film was then tested for its contact angle.

[0021] Preparation method 1: Deposition of a single layer of NiO by reactive magnetron sputtering x film Reactive magnetron sputtering deposition of monolayer NiO x The main processes for thin films include: (1) Take an ITO conductive glass substrate, clean it in acetone, ethanol and deionized water by ultrasonication, dry it with nitrogen, and then put it into the cavity of the vacuum magnetron sputtering system and fix it on the stage. (2) Close the chamber door and evacuate the chamber until the vacuum level is below 2.0 × 10⁻⁶. -6 Pa; (3) Shield the substrate, open the gas valve, inject argon gas into the cavity at a speed of 30 sccm, and adjust the sputtering power to 80-150W and the working gas pressure to 0.1-1.0Pa. Perform pre-sputtering for 5-10 minutes to clean the surface of the tweezers target. (4) After the power stabilizes, set the deposition time, open the baffle, inject argon into the cavity at a rate of 30-100 sccm, and inject oxygen into the cavity at a rate of 1-5 sccm. Perform the sputtering deposition process at room temperature. The film thickness is adjusted by controlling the deposition time. The film thickness deposited in this experiment is 35 nm. (5) After sputtering is complete, turn off the power supply, then close the gas valves in sequence and open the vent valve. After the gas pressure inside the chamber is balanced with the ambient pressure, open the chamber door and take out the sample. The obtained NiO x The thin film is designated as Thin Film No. 1.

[0022] Preparation method 2: ALD deposition of monolayer NiO x film Ald deposition of a single layer of NiO x The main processes for thin films include: (1) Take an ITO conductive glass substrate, clean it by ultrasonication in acetone, ethanol and deionized water in sequence, dry it with nitrogen gas, and then put it into the ALD reaction chamber and fix it on the stage. (2) Close the reaction chamber and evacuate the chamber to the required base pressure (2×10). -5 Pa); (3) After heating the reaction chamber and substrate to 150-250℃, start the ALD cycle; (4) The sequence of a single ALD cycle is as follows: A. Pulse a nickel metal precursor (selected from any one of bis(cyclopentadiene)nickel, nickel acetylacetonate, and nickel amide) into the reaction chamber for 0.5-2 seconds; B. Stop the introduction of the nickel metal precursor into the reaction chamber and purge the reaction chamber with nitrogen gas for 10-30 seconds; C. Pulse a reactive oxidant (selected from any one of ozone, oxygen plasma, and water vapor) into the reaction chamber for 2-5 seconds; D. Stop the introduction of the reactive oxidant and purge the reaction chamber with nitrogen gas for 10-30 seconds; Completing steps A to D completes one ALD cycle. By repeating the ALD cycle described above, the desired NiO can be deposited on the glass substrate. xThe film thickness was adjusted by controlling the number of ALD cycles. In this experiment, the film thickness was 35 nm. (5) After deposition, the sample and reaction chamber were cooled to room temperature under a nitrogen purging atmosphere. The pressure inside the reaction chamber was then adjusted to be equal to the external atmospheric pressure. The chamber door was then opened to remove the sample, and the obtained NiO was obtained. x The film is designated as film number 2.

[0023] Preparation Method 3: Reactive Magnetron Sputtering-ALD Deposition of Bilayer Composite NiO x film The reasons for choosing the "reactive magnetron sputtering-ALD" deposition process sequence are as follows: 1. Process compatibility and interface damage control High-energy particle damage in magnetron sputtering: The magnetron sputtering process involves high-energy particles and plasma. If deposited directly on perovskite or other sensitive substrates, the bombardment effect can cause severe interface damage, resulting in defects and significantly reducing device performance.

[0024] Mildness and Conformity Preservation of ALD: ALD is a thermally driven or plasma-assisted surface chemical reaction with a mild process and virtually no physical bombardment. Using it as a second layer allows for non-destructive sputtering of NiO on pre-formed magnetron-sputtered surfaces. x Layer-by-layer growth.

[0025] 2. Thin Film Growth Modes and Structural Requirements Magnetron sputtering requires "nucleation centers": Magnetron sputtering thin film growth follows an island-like growth pattern, requiring a stable and uniform substrate to form a continuous film. If deposition is first performed on a rough or porous surface, the film quality will be poor.

[0026] ALD's unparalleled coverage: ALD is grown layer-by-layer, exhibiting excellent step coverage and conformal properties. It can perfectly cover relatively rough magnetron sputtered NiO. x The surface is "polished" to be smooth and dense without introducing pinholes.

[0027] Structural-functional differentiation: The first layer (magnetron sputtering): primarily serves the function of charge transport. A certain thickness is required to provide lateral conductivity; therefore, high-speed sputtering is a more economical and efficient method for its fabrication.

[0028] The second layer (ALD) primarily serves for interface modification and passivation. It only requires a very thin layer, which is precisely its advantage. Using a slow ALD to fabricate a thick substrate is uneconomical.

[0029] 3. Optimization of electrical performance Volume transport vs. interface extraction: Magnetron sputtering NiO x High conductivity and hole mobility can usually be obtained through regulation, making it suitable as a bulk transport layer.

[0030] ALD deposited NiO x While their intrinsic conductivity is often low, their excellent interfacial properties ensure efficient extraction of holes from the perovskite to the transport layer and suppress interfacial recombination.

[0031] Energy level matching: First, a bottom layer with a specific work function is formed using magnetron sputtering, and then an ALDNiO layer is formed using a top layer. x Fine-tuning the work function of the outermost surface can achieve better alignment with the top of the valence band of the perovskite layer, reducing the hole injection barrier.

[0032] 4. Defect Management and Passivation Defects in magnetron sputtering layers: Although magnetron sputtered thin films have good electrical conductivity, they usually have a high density of defect states (dangling bonds, grain boundaries, etc.) on their surface and at grain boundaries.

[0033] The "repairing" effect of ALD: The post-deposited ALD layer can effectively passivate the underlying magnetron sputtered NiO. x These surface defects form a high-quality, low-defect-density interface that contacts the overlying perovskite layer. This significantly reduces non-radiative recombination losses and is key to improving the device's open-circuit voltage.

[0034] 5. Industrialization and Cost Considerations Deposition rate: Magnetron sputtering has a fast deposition rate and is suitable for preparing thicker substrates (e.g., 20-50 nm). If ALD is used to deposit this thickness, the time cost will be very high.

[0035] Process economy: First, use rapid sputtering to complete the deposition of most of the material, and then use fine but slow ALD to complete the most critical surface and interface modification. This is a reasonable strategy to optimize production costs while ensuring performance.

[0036] In summary, the method of "first preparing the first thin film using reactive magnetron sputtering, and then depositing the second thin film on the first thin film using ALD deposition technology" was selected to prepare a bilayer composite NiO. x Thin film. Specifically, following the process flow of preparation method one, a 30nm thick NiO film is reactively magnetron sputtered onto an ITO transparent conductive substrate. x A thin film is then prepared by ALD deposition of a 5 nm thick NiO layer on the thin film, following the process flow of preparation method two. x The resulting thin film is designated as film number 3.

[0037] Contact angle tests were performed on films 1 to 3 above. The test structures are shown in [reference needed]. Figure 1As shown, the contact angle of film 1 is 35.2°, film 2 is 25.3°, and film 3 is 29.4°. A smaller contact angle indicates better surface wettability. Therefore, by magnetron sputtering NiO... x NiO is then deposited on the thin film by ALD. x Thin films significantly improve the performance of single magnetron NiO x Surface wettability of thin films.

[0038] Example 2: Study on NiO prepared by different methods x Carrier transport properties at the interface between thin films and perovskite thin films Perovskite films were deposited on films 1 to 3 prepared in Example 1 according to the perovskite film deposition method described below. These films are referred to as perovskite film I (I-PVK), perovskite film II (II-PVK), and perovskite film III (III-PVK). The perovskite films were characterized by steady-state fluorescence spectroscopy (PL) and time-resolved fluorescence spectroscopy (TRPL) to analyze the carrier diffusion and migration properties at the HTL-PVK interface.

[0039] The perovskite thin film deposition method is as follows: a pre-prepared 1.73 M perovskite precursor solution (Cs) is spin-coated onto a prepared substrate. 0.05 MA 0.02 FA 0.93 Pb(I 0.98 Br 0.02 )3) First, rotate at 1000 rpm for 10 s, then rotate at 4500 rpm for 45 s. When there are 15 s left in the second spin coating process, continuously add 180 μL of chlorobenzene as an antisolvent to the rotating perovskite wet film. Then immediately transfer the obtained perovskite wet film to the heating stage and anneal at 100℃ for 30 min.

[0040] First, NiO was analyzed using PL. x Carrier diffusion and migration properties between the / PVK interface. See also Figure 2 As shown, the PL spectra of PVK films deposited on different HTLs are presented. The peak value of the emission peak of the perovskite film No. 3 (HTL is film No. 3) is significantly lower than that of the perovskite film No. 1 (HTL is film No. 1) and the perovskite film No. 2 (HTL is film No. 2). This indicates that the radiative recombination intensity of the perovskite deposited on film No. 3 (bilayer composite NiOx film) is reduced. Therefore, the hole transport layer can quickly extract hole carriers inside the perovskite and transport them to the anode of the battery. The emission peak intensity of the perovskite film No. 3 is quenched, indicating that it has a stronger ability to extract and transport photogenerated hole carriers.

[0041] On the other hand, the charge transport properties at the HTL / PVK interface were further investigated using TRPL. See [link to related information]. Figure 3 The figure shows the TRPL spectra of PVK films deposited on different HTLs. The perovskite carrier lifetime of the No. Ⅲ perovskite film is significantly reduced, which further indicates that the carrier extraction and transport speed is accelerated, which can suppress the undesirable recombination process that occurs at the interface.

[0042] Example 3: Performance Analysis of Inverted Perovskite Solar Cell Device I. Fabrication of Inverted Perovskite Solar Cells The structure of an inverted perovskite solar cell consists of, in sequence, a conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode. The fabrication methods for each layer are detailed below.

[0043] 1. Conductive Substrate: Immerse the purchased ITO conductive glass sequentially in acetone, ethanol, and deionized water, then ultrasonically clean for 20 minutes to remove fine particulate impurities from the surface. After ultrasonic cleaning, use a nitrogen gun to dry any remaining liquid on the surface. Place the conductive glass with the etched side facing up in a sealed glass container for later use. Before handling the ITO conductive glass, transfer it to a UV cleaner and treat it with ultraviolet ozone for 15 minutes to remove surface impurities and organic matter, and improve wettability.

[0044] 2. Hole transport layer: Prepared according to methods one to three of Example 1.

[0045] 3. Perovskite layer: Refer to the perovskite thin film deposition method in Example 2.

[0046] 4. Electron Transport Layer: After cooling the prepared perovskite film, a pre-prepared 1.5 mg / ml solution of 1,4-phenylenediamine dihydroiodide (PDADI) was spin-coated at 4500 rpm for 30 seconds, followed by annealing at 100°C for 5 minutes. After cooling, 30 nm of C60 and 6 nm of bath copper ether (BCP) were deposited on the surface of the perovskite film.

[0047] 5. Metal Electrode: After the above steps are completed, a 120nm Ag layer is deposited on the thin film as the metal back electrode, thus completing the fabrication of the perovskite solar cell. The effective area of ​​the device is 0.0872mm². 2 .

[0048] II. Device Performance Testing Methods Using a xenon lamp solar simulator (AM1.5G, 100 mWcm) -2 The prepared solar cell device was subjected to performance testing to obtain the following photoelectric performance parameters: open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF), and power conversion efficiency (PCE).

[0049] III. Device Samples Used for Performance Testing The differences between the various device samples are shown in Table 1 below.

[0050] Table 1. Differences between devices in each processing group

[0051] Note: The difference between treatment 5 and treatment 4 is that treatment 5 involves reactive magnetron sputtering of NiO. x After the film is formed, it is transferred to a heating stage and air-annealed at 150-350℃ for 30-60 minutes. After annealing, it is slowly cooled to room temperature and then transferred into the ALD reaction chamber for ALD deposition.

[0052] IV. Device Performance Test Results according to Figure 4 The JV curves were used to calculate the photoelectric performance parameters of each device, and the results are shown in Table 2 below.

[0053] Table 2. Optoelectronic performance parameters of the device

[0054] As can be seen from Table 2 above, the hole transport layer uses a double-layer composite NiO of a certain thickness. x Compared to batteries fabricated using monolayer thin films (Controls 5 and 6), the thin-film-based batteries (Treatments 1 to 5) showed significantly improved device performance, with Treatment 5 exhibiting the best performance. A bilayer composite NiO layer was used in the hole transport layer. x In the thin-film batteries, compared with treatment 2, control 1 showed a 1 nm reduction in ATL deposition thickness and a 1.33% decrease in PCE. Compared with treatment 3, control 2 showed a 20 nm increase in ATL deposition thickness and a 0.76% decrease in PCE. Compared with treatment 2, control 3 showed a 5 nm increase in reactive magnetron sputtering thickness and a 1.91% decrease in PCE. Compared with treatment 1, control 4 showed a 2 nm reduction in reactive magnetron sputtering thickness and a 1.18% decrease in PCE. This indicates that both excessively thick and excessively thin reactive magnetron sputtering films and ATL deposition films can lead to a decrease in device performance.

[0055] When magnetron sputtered NiO x Excessive film thickness leads to the absorption of more incident photons in the visible light region, reducing the number of photons reaching the perovskite film. Simultaneously, interface roughness and defects increase, affecting magnetron sputtered NiO. x Thin films typically exhibit columnar crystal growth characteristics, and surface roughness increases significantly with increasing thickness. A rough underlayer poses a challenge to subsequent ALD layer deposition, ultimately leading to poor perovskite crystal quality and intensified interfacial recombination.

[0056] NiO grown by ALD x NiO typically exhibits low electrical conductivity (low hole mobility) when grown by ALD. x When the film is too thick, holes encounter significant resistance when passing through this "insulating" thick film from the perovskite. The excessively thick ALD layer completely covers and dominates the charge transport process, making the underlying magnetron sputtered NiO... x The high conductivity advantage of the thin film layer is "shielded", and the ALD deposition rate is extremely slow (usually <0.1 nm / cycle). The deposition of excessively thick ALD takes a very long time, which cannot meet the needs of efficient production.

[0057] For the reasons mentioned above, reactive magnetron sputtering of NiO is preferred. x The film thickness is 10-30 nm, and NiO is deposited in atomic layers. x The film thickness is 5 nm. Magnetron sputtered NiO with a thickness of 10-30 nm. x The thin film layer is sufficient to form a continuous, low-resistance conductive network, providing efficient lateral and longitudinal transport channels for photogenerated holes and ensuring an excellent fill factor; and this thickness of magnetron sputtered NiO x Thin films typically possess moderate roughness and good crystallinity, providing a stable substrate for the uniform growth of subsequent ALD layers. A 5nm thick ALD layer is sufficient to cover surface defects (dangling bonds, grain boundaries, etc.) in the underlying magnetron sputtering layer, forming a new surface that is atomically smooth and chemically homogeneous. This effectively suppresses interfacial nonradiative recombination and increases the open-circuit voltage. Furthermore, 5nm is a critical thickness where quantum tunneling remains effective; holes can easily tunnel through this ultrathin film without significantly increasing the series resistance. The ALD layer deposited on the magnetron sputtering layer is more like a "selective contact" layer than a bulk transport layer. The extremely smooth surface of the ALD layer, with controllable hydrophilicity, facilitates the uniform spreading of the perovskite precursor solution and guides the formation of high-quality perovskite films with large grains and low defects.

[0058] V. Testing the Stable Output Performance of the Device Based on the device performance tests described above, treatment 5 (HTL layer with 30nm magnetron sputtering + 5nm ATL deposition), control 5 (HTL layer with 35nm magnetron sputtering), and control 6 (HTL layer with 35nm ATL deposition) were selected for steady-state power output testing to evaluate their performance under operating conditions. The tests were conducted under standard illumination conditions (AM 1.5G, 100 mW / cm²), with the device bias fixed at the maximum power point, and the output continuously monitored for 600 seconds.

[0059] See test results Figure 5 As shown, from Figure 5As can be seen, during the continuous operation of 600 seconds, none of the three groups of devices exhibited significant performance degradation, and their steady-state output power curves remained stable. This initially demonstrates the basic stability of each device under short-term operation. However, the key difference lies in the absolute value of the steady-state output power: the steady-state power output value of the device in treatment group 5 was significantly higher than that of control groups 5 and 6. This directly indicates that the double-layer composite NiO x The thin-film HTL layer enhances the core photoelectric conversion performance of inverted perovskite solar cells.

[0060] The above performance analysis and test results clearly demonstrate that the reactive magnetron sputtering NiO provided by this invention... x Thin film and atomic layer deposition of NiO x Thin film composite bilayer NiO x The application of thin films in the hole transport layer of inverted perovskite solar cells produced an unexpected synergistic enhancement effect.

[0061] First, this invention solves the performance bottleneck of a single technical path: single magnetron sputtering of NiO x Although the layer has high bulk conductivity, intrinsic defects on its surface lead to severe interfacial recombination, limiting hole injection efficiency; a single ALD-NiO layer... x While the layer provides excellent interface quality, its low intrinsic conductivity constitutes a bottleneck for bulk transport. Both of these single structures limit the ultimate performance ceiling of the device due to their inherent defects.

[0062] Secondly, this invention achieves optimal integration of performance factors: the dual-layer structure of this invention creatively combines the high conductivity advantage of magnetron sputtering with the ultra-high interface quality advantage of ALD process. Specifically, the bottom layer is magnetron sputtered NiO. x As a highly efficient bulk transport channel, it ensures the rapid collection and removal of holes; the top layer of ultrathin ALD-NiO x As an ideal interface modification layer, it significantly reduces interface recombination loss and optimizes energy level alignment. The synergistic effect of the two enables the entire hole transport process, from generation in the perovskite light-absorbing layer, through interface injection, to final collection by the electrodes, to achieve global optimization, thereby significantly improving the steady-state output capability of the device at maximum power point.

[0063] In summary, it can be seen that the reactive magnetron sputtering of NiO provided by this invention... x Thin film and atomic layer deposition of NiO x Thin film composite bilayer NiO xThin films, as hole transport layers in inverted perovskite solar cells, possess both high conductivity and excellent interface quality. They can effectively reduce nonradiative recombination at the perovskite light-absorbing layer / hole transport layer interface, thereby improving the photoelectric conversion efficiency, fill factor, and open-circuit voltage of inverted perovskite solar cells and significantly enhancing their steady-state output performance.

[0064] It is understood that this invention is not limited to the field of inverted perovskite solar cells, and its concept can be extended to other devices that need to balance bulk transport performance and interface quality, such as other types of perovskite optoelectronic devices (such as light-emitting diodes, photodetectors) or other semiconductor heterojunction devices.

[0065] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hole transport layer for an inverted perovskite solar cell, characterized in that: The hole transport layer is reactive magnetron sputtered NiO. x Thin film and atomic layer deposition of NiO x Thin film composite bilayer NiO x Thin film, the reactive magnetron sputtered NiO x A thin film with a thickness of 5-50 nm is deposited on a conductive substrate; the atomic layer is deposited as NiO. x The thickness of the thin film is 3-30 nm.

2. The hole transport layer according to claim 1, characterized in that: The reactive magnetron sputtering NiO x The film thickness is 10-30 nm; the atomic layer deposition NiO x The thickness of the thin film is 5 nm.

3. The method for preparing the hole transport layer according to claim 1 or 2, characterized in that: Includes the following steps: Step 1: Reactive magnetron sputtering of NiO x Thin film: The conductive substrate is placed in the cavity of the vacuum magnetron sputtering system, and the cavity is evacuated to a base vacuum level of less than 2.0 × 10⁻⁶. -6 After Pa, argon and oxygen are introduced into the cavity to deposit a 5-50 nm thick NiO layer on the conductive substrate. x The first film layer is obtained. During the deposition process, the temperature of the conductive substrate is controlled at 20-25℃, the sputtering power is 80-150W, and the working gas pressure is 0.1-1.0Pa. The flow rate of argon gas into the cavity is 30-100sccm, and the flow rate of oxygen gas into the cavity is 1-5sccm. Step 2: Atomic layer deposition of NiO x Thin film: The first film layer is transferred into the ALD reaction chamber, and the temperature inside the ALD reaction chamber is controlled at 150-250℃. The NiO layer in the first film layer... x NiO 3-30 nm thick was cyclically deposited on the thin film using ALD. x film; The ALD cyclic deposition is repeated 100-300 times; The sequence of a single ALD deposition in the ALD cyclic deposition includes: A. Pulsed nickel metal precursor: The nickel metal precursor is pulsed into the ALD reaction chamber for 0.5-2 seconds; B. First purging: Purge the ALD reaction chamber with nitrogen for 10-30 seconds; C. Pulsed reaction oxidant: The reactive oxidant is pulsed into the ALD reaction chamber for 2-5 seconds; D. Second purging: Purge the ALD reaction chamber with nitrogen for 10-30 seconds.

4. The preparation method according to claim 3, characterized in that: The nickel metal precursor is selected from any one of bis(cyclopentadiene)nickel, nickel acetylacetonate, and nickel amide.

5. The preparation method according to claim 3, characterized in that: The reactive oxidant is selected from ozone, oxygen plasma, and water vapor.

6. The preparation method according to claim 3, characterized in that: NiO reactively sputtered on the conductive substrate in step 1 x The thickness of the thin film is 10-30 nm.

7. The preparation method according to claim 3, characterized in that: NiO cyclically deposited by ALD in step 2 x The thickness of the thin film is 5 nm.

8. The preparation method according to claim 3, characterized in that: The NiO deposited in step 1 x The thin film is annealed before atomic layer deposition in step 2.

9. The preparation method according to claim 8, characterized in that: The annealing treatment is performed at a temperature of 150-350℃ for 30-60 minutes, and the annealing atmosphere is selected from at least one of air, oxygen, and nitrogen.

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